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The selection of parameters affects the surface roughness in the additive manufacturing process. This study aims to determine the optimal combination of input parameters for predicting and minimising the surface roughness of samples produced by Fused Deposition Modelling on a 3D printer using a cascade-forward neural network (CFNN) and genetic algorithm. Box–Behnken Design with four independent printing parameters at three levels is used, and 25 parts are fabricated with a 3D printer. Roughness tests are performed on the fabricated parts. Models generated by the hybrid algorithm achieve the best results for predicting and optimising surface roughness in 3D-printed parts. The surface roughness prediction accuracy of the trained CFNN with optimised parameters is more accurate compared to previous random test results.

Highly filled conductive polymer composites (CPCs) are widely used in applications such as bipolar plate materials for polymer electrolyte membrane fuel cells and redox flow batteries, electromagnetic interference shielding and sensors due to their useful electrical properties. A common method for determining through-plane electrical conductivities $\left(\sigma_{\rm tp} \right)$ of such highly filled CPCs applies a conductive carbon paper between electrodes and sample with application of external pressure to improve electrical contact. We show the pressure-dependence of the measured $\sigma_{\rm tp}$ can be eliminated by using a liquid metal such as the gallium-indium eutectic alloy (EGaIn) as contact material. Results indicate that EGaIn reduces contact resistances and cause three to five times larger $\sigma_{\rm tp}$ compared to measurements with carbon paper contacts and pressures up to 20 bar.

Rotational abrasive finishing (RAF) is a new nano-finishing technique in which the finishing forces are applied to the workpiece by the opposite rotations of a stirring-blades and the workpiece. The RAF process allows for finishing the inner and outer surfaces of workpieces, particularly complex ones with axial symmetry. The present study aims to propose a new theoretical model to obtain deeper insights into the material removal mechanism, surface roughness prediction, and forces in RAF process. Since the abrasive-workpiece interaction is random and complex in nature in the RAF, some initial assumptions were considered. To validate the repeatability of the experimental results, the experiments were designed based on the Response surface method (RSM). To validate the new proposed theoretical model, a number of influential parameters were investigated. It was found that the stirring-blade speed (S), working gap (W), and abrasive grain size (A) had significant effects on Ra. The minimum surface roughness (Ra) was obtained to be 46.87 nm at a rotational speed of 600 rpm, a working gap of 1 mm, and grain size of 18 µm. The experimental results were relatively in good agreement with the theoretical results so that the maximum error was about 24%. This can be assumed that the most important explanation for the difference between the theoretical and experimental results can be attributed to the initial theoretical assumptions. Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura

Roughness, defined as unevenness of material surfaces, plays an important role in determining how engineering components or natural objects interact with other bodies and their environment. The emergence of fractal roughness on natural and engineered surfaces across a range of length scales suggests the existence of common processes and mechanisms for nucleation and evolution of roughness. In this article, we review recent advances in understanding the origins of roughness and topography evolution on natural and engineered surfaces and their connection with subsurface deformation mechanisms. Directions for future research toward understanding the origins of roughness on solid surfaces are discussed.

Polymeric materials are inevitably used in dental applications. Dental prostheses are cleaned during their service life, and surface roughness is an important criterion for these polymeric materials. In this study, the efect of diferent denture cleaning methods on the surface roughness and color stability of polyether ether ketone (PEEK) dental materials was studied. Seventy disk-shaped (10×3 mm) specimens were fabricated and divided into seven groups (n=10) according to the cleaning procedure. One of these groups subjected to distilled water was the control group. Other three groups were subjected to daily cleansing with denture cleaners (5% sodium hypochlorite, alkaline peroxide, chlorhexidine gluconate solution) and the other three groups were subjected to mechanical cleaning with a toothbrush with three diferent dentifrices (toothpaste, soap, and denture cleansing gel). The surface roughness values (Ra) were measured with a proflometer before (Ra0) and after cleaning procedures for 270 days (Ra1). CIELab color parameters of each specimen were measured with a spectrophotometer before and after 7 days of storage in a coffee solution. Color diferences were calculated, and data were statistically analyzed with one-way ANOVA and the Tukey HSD test (α=.05). For all test groups, Ra0 and Ra1 values were lower than the plaque accumulation threshold level (PATL) of 0.200 μm. For both Ra and ΔE00 values, the efect of the cleaning method was not statistically signifcant (P>0.05). Also, no signifcant diference was observed for Ra0, Ra1, and ΔE00 values between the test groups (P>.05). It was concluded that considering the color stability and surface roughness, many cleaning procedures can be used safely for PEEK polymers.

Three-dimensional (3D) printing of polylactic acid using the fused filament fabrication approach is a widely used additive manufacturing method in various fields, despite the historical issue of substantial surface roughness in fused filament fabrication products. Several strategies have been utilized to minimize the surface roughness of 3D-printed items. However, laser polishing is a novel technique for reducing surface roughness and improving other material qualities. In this study, polylactic acid was examined using the laser polishing method for surface roughness and mechanical properties, such as tensile and flexural strength and laser scan time. Several trials were conducted to determine how changing the laser’s characteristics may affect the materials’ surface quality and mechanical qualities. Before the final test, preliminary tests were performed to determine the lowest potential heat-affected zone. Laser polishing reduced surface roughness by more than 88.8% (from 7.8 µm to 0.87 µm). The tensile strength of the specimen increased by 14.03%, from 39.2 MPa to 44.7 MPa. Polylactic acid had a constant flexural strength of 70.1 MPa before and after polishing, and the laser scan time for samples was 19.4 s. Polished morphologies were studied to learn more about the microstructure. These findings show that laser polishing can improve and modify the surface properties of a fused filament fabrication product, which can benefit the industry and researchers.

This study focused on chromium addition (0 wt%, 3 wt%, 6 wt%, 9 wt% and 12 wt%) on the boride layer formation, microhardness, fracture toughness and elevated temperature friction and wear behaviour of alloys formed by powder metallurgy (P/M). The boride layers obtained on P/M alloys were characterized by examining density, porosity, surface roughness, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray difraction, surface proflometry, microhardness, and fracture toughness. The addition of Cr has a signifcant efect on both boride layer formation and friction-wear behaviour of P/M alloys. Increasing the Cr addition up to 6 wt% has an improving efect on the microhardness, fracture toughness and wear resistance of the P/M alloys, whereas in the case of 9–12 wt% Cr addition causes exfoliation in the boride layer and low fracture toughness, thus reducing wear resistance. Coefcients of friction and wear volume losses at elevated temperatures are higher than room temperature. The best wear resistance at room temperature was obtained in the sample containing 3 wt% Cr with the highest fracture toughness, while the best wear resistance at 250 °C and 500 °C was obtained in the sample containing 6 wt% Cr, where the highest hardness value was obtained.

Quantum plasmonics aims to harness the deeply sub-wavelength confinement providedby plasmonic devices to engineer more efficient interfaces to quantum systems, in particular single emitters. Realizing this vision is hampered by the roughness induced scattering and loss inherent in most nanofabricated devices. In this work, we show evidence of a reactive ion etching process to selectively etch gold along select crystalline facets. Since the etch is facet selective, the sidewalls of fabricated devices are smoother than the lithography induced line-edge roughness, with the prospect of achieving atomic smoothness by further optimization of the etch chemistry. This opens up a route towards fabricating integrated plasmonic circuits that can achieve loss metrics close to fundamental bounds.

Viscoelasticity and roughness are among the possible causes of the adhesive hysteresis displayed by soft contacts. Viscoelasticity causes an increased effective work of adhesion due to stiffening of the contact, while roughness is responsible for elastic instabilities. Herein, we explore the interplay between viscoelasticity and roughness by simulating in two dimensions the retraction of a rigid cylinder, with wavy surface profile, from a viscoelastic half-space. The wave amplitude and length are varied to induce instabilities in the load–to–area response, while the retraction velocity is increased to promote viscoelasticity. Results show that, in the regime where viscoelasticity is confined to the edges of the wavy contact, the contributions of viscoelasticity and waviness to adhesive hysteresis are nearly independent and additive. At low retraction rates, the instabilities in the load-area curve typical of rough elastic contacts are suppressed by viscoelasticity: the contact stiffens to promote a stable decrease of the contact area with load. This occurs with a minimal change in work of adhesion. However, when the instantaneous limit is met at high retraction rates, mechanical instabilities appear. LN acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 681813).

The expected quality indicator in the manufacturing industry is the surface roughness (R a). The effects of milling operation parameters on the axial forces and surface roughness of AA 2024-T351 alloy plate were studied. Experiments were carried out on an AA 2024 material using a Hartford four-axis computer numerical control vertical processing center machine and a carbide insert. Axial forces were measured by using a three-component cutting force dynamometer. R a values ranged from 0.2583 to 0.8833 μm and the cutting force from 76 to 305 N. Experimental results showed that cutting forces rose with an increase in cutting speed but R a values decreased with a rise in cutting speed. Also, the depth of cut was the commanding factor followed by spindle speed and feed per tooth. This indicated that cutting depth was the most important factor among the design parameters, followed by cutting speed and feed per tooth. Besides, the response surface methodology was used to investigate the milling parameters on R a and axial forces. Variance analysis was conducted to find the contribution of each component to the results of roughness and forces. Scanning electron microscopy analysis was also performed to see the abrasions on the cutting tool surface.

Industrial waste is a problem for companies as well as for the environment. In recent years, an alternative solution to this problem has been found – the use of waste in the production of new composite materials. It is not enough to produce only the composite. The machinability of the composite produced should also be investigated. This study obtained the new composite material using industrial waste produced by glass fibre-reinforced plastic pipes. The terephthalic resin was used as a matrix material. The waste powder was used as a filling material in the ratio of 30, 40 and 50% by weight compared to the matrix material. The machinability of produced composites was investigated according to three parameters with three levels. According to the experimental results, the optimum cutting parameters are obtained, depending on surface roughness.

Electroless ZnO-reinforced Ni–P coatings are developed on mild steel substrates in the Electroless bath, which contains an optimum concentration of ZnO nanoparticles. This work focuses on the characteristics and properties of the Ni–P–ZnO coatings developed at different concentrations of reducing agent (sodium hypophosphite). Results confirm that the reducing agent greatly influences the deposition rate, surface roughness, hardness, and corrosion resistance of the coating. Reducing agent concentration influences the phosphorus present in the coating. An increase in the amorphous nature of the coating with an increase in reducing agent concentration improves the resistance to corrosion of the coating, but at the same time, it decreases the microhardness of the coating. High phosphorus deposition at the maximum amount of reducing agent concentration lowers the microhardness of the coating. The Hard Ni3P crystalline phase formed at 400 °C enhances the resistance to corrosion and microhardness of the coating. Scanning electron microscopy and X-ray diffraction studies are used to characterize the Ni–P–ZnO coating. The microhardness and corrosion resistance of the coating were evaluated using a Vickers microhardness tester and potentiodynamic polarization studies.

Surface mechanical nano-alloying treatment (SMNAT) was employed to fabricate a nanostructured Ti coating on LZ91 Mg–Li alloy. Microstructure, surface hardness and in-vitro biocompatibility of the Ti-coated sample were investigated in comparison with those of an untreated sample. Experimental results showed that a nanostructured Ti coating with a thickness of 35 to 60 μm was formed after SMNAT for 2 h. The average grain size in the top surface of the Ti coating was about 30 nm. The surface of the Ti coating is rougher than that of the untreated LZ91 sample, in which the values of Ra, Rq and Rz were 7.83, 9.57 and 14.85 μm, respectively. The hardness of the Ti coating top surface was about 483 HV. Cell proliferation and differentiation on Ti coated samples were enhanced relative to those on the untreated samples.

Solar cells based on thin crystalline silicon (c-Si) substrates have the potential to provide relevant efficiencies with less material. In this article, we report on the fabrication of thin solar cells starting from a 20 μ m-thick c-Si wafer. Special attention is paid to optical performance of the rear surface where we need very high internal reflection and light scattering to improve light trapping properties of the device. In this sense, we introduce a texturization of the rear surface, which is excellently passivated by aluminium oxide films. In addition, for the rear contacts we use metal-covered wide-bandgap materials to improve back reflectance with a Vanadium Oxide/c-Si heterojunction for the emitter regions while the base contacts are defined by laser processing phosphorus doped amorphous silicon carbide films. Best solar cell has a reasonable efficiency of 8.7% and, more importantly, external quantum efficiency measurements demonstrate a better performance for photons with λ > 900 nm than in the case of a flat rear surface.

Silicon rubber has been widely used in the biomedical field due to its excellent mechanical properties and physiological inertia. However, the hydrophobic properties of silicon rubber surfaces limit their further application. Therefore, constructing a silicon rubber coating with hydrophilic and low-friction surface properties would be highly significant. Existing methods to achieve such coatings, including grafting polymer brushes and the deposition of hydrophilic materials, suffer from several deficiencies such as complicated coating processes and insufficient coating firmness. In this paper, we report a hydrophilic polymer poly(hydroxyethyl methacrylate) (PHEMA) coating that can easily coat the surface of silicon rubber to provide low-friction performance. Sample silicon rubber was treated with benzophenone and hydroxyethyl methacrylate monomer solution in turn. The as-prepared coating was characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, white light interference, and MFT-5000 wear test. The results indicated that the PHEMA coating had excellent hydrophilic properties (with a low contact angle of 9.39°) compared to uncoated silicon rubber. As the concentration of glycerol in the monomer solution was increased, the thickness and surface roughness of the as-prepared coating gradually decreased. The coating was firmly adsorbed on the substrate, and it had a zero-class bonding strength. In addition, the as-prepared coating demonstrated good friction-reduced properties, with the coefficient of friction being reduced by 98.0% compared with the uncoated silicon rubber in simulated blood. In summary, a hydrophilic and low-friction coating was successfully prepared using a simple method, and the results reported herein provide valuable insight into the surface design of similar soft materials.

Here, we report the structural and electronic modification induced in chemical vapor deposited graphene by using swift heavy ions (70 MeV Ni6+).Raman spectroscopy was used to quantify the irradiation-induced modification in vibrational properties. The increase in defect density with fluence causes an increase in the intensity ratio of its characteristic Raman D and G band. The increase in defect density also results in a decrease in crystallite size. The changes in the crystal structure are observed from X-rays diffraction measurement. Swift heavy ion irradiation induced defect, modified the surface roughness and surface potential of graphene thin film as measured from atomic force microscopy and scanning Kelvin probe microscopy respectively. The increase in the work function, surface roughness as well as defect concentration with fluence, indicate the possibility of linear correlation between them. Presence of defects in graphene sheets strongly affects surface electronic and optical properties of the material that can be used to tailor the optoelectronics device performance.

The Reynolds number of turbine blades can be reduced by decreasing the surface roughness of the blades, which decreases energy loss in energy production systems. Due to the challenges of the polish...

Identifying air-stable two-dimensional (2D) ferromagnetism with high Curie temperature (Tc) is highly desirable for its potential applications in next-generation spintronics. However, most of the work reported so far mainly focuses on promoting one specific key factor of 2D ferromagnetism (Tc or air stability), rather than comprehensive promotion of both of them. Herein, ultrathin Cr1−xTe crystals grown by chemical vapor deposition (CVD) show thickness-dependent Tc up to 285 K. The out-of-plane ferromagnetic order is well preserved down to atomically thin limit (2.0 nm), as evidenced by anomalous Hall effect observed in non-encapsulated samples. Besides, the CVD-grown Cr1−xTe nanosheets present excellent ambient stability, with no apparent change in surface roughness or electrical transport properties after exposure to air for months. Our work provides an alternative platform for investigation of intrinsic 2D ferromagnetism and development of innovative spintronic devices.

Abstract Thermoplastic semi-crystalline polymers are excellent candidates for tissue engineering scaffolds thanks to facile processing and tunable properties, employed in melt-based additive manufacturing. Control of crystallization and ultimate crystallinity during processing affect properties like surface stiffness and roughness. These in turn influence cell attachment, proliferation and differentiation. Surface stiffness and roughness are intertwined via crystallinity, but never studied independently. The targeted stiffness range is besides difficult to realize for a single thermoplastic. Via correlation of thermal history, crystallization and ultimate crystallinity of vitamin E plasticized poly(lactide), surface stiffness and roughness are decoupled, disclosing a range of surface mechanics of biological interest. In osteogenic environment, human mesenchymal stromal cells were more responsive to surface roughness than to surface stiffness. Cells were particularly influenced by overall crystal size distribution, not by average roughness. Absence of mold-imposed boundary constrains makes additive manufacturing ideal to spatially control crystallization and henceforward surface roughness of semi-crystalline thermoplastics. Graphic abstract

7075 aluminum alloy is widely used due to its great performance, especially in aerospace area. In this paper, ultrasonic-assisted grinding technology is used to process 7075 aluminum alloy. The data is obtained through experiments, and the surface roughness and morphology of ultrasonic assisted grinding and conventional grinding under different spindle speeds, feed rates, and amplitudes are analyzed. Research has found that the increase in spindle speed and amplitude will improve the quality of the machined surface and reduce the surface roughness by 82.1% and 36%. However, with the increase of feed rate, the surface quality decreased significantly, and the surface roughness increased by 55.6%. The surface micro-morphology of the machined workpiece is observed, and the effects of different processing parameters on the surface micro-morphology are obtained.

In this research, a one-way abrasive flow machining (AFM) was sketched and built, and the impact of temperature on surface roughness ( R a ) values and material removal rate ( M R R ) before and after each test have been investigated considering the SiC. Al2O3, and B2O3 particles as abrasive particles. The abrasive particles were dispersed at 35 wt.% in the prepared media. The findings revealed that the media containing Al2O3 abrasive particles had higher surface roughness compared to the SiC and B2O3 particles. The maximum variation of surface roughness for SiC, Al2O3, and B2O3 particles was observed at − 196 °C, which was 2.991, 2.588, and 1.684, respectively. In addition, the material removal rate values decreased for all the prepared samples as the temperature was reduced. At lower temperatures, lower material removal rate values were recorded since the viscosity of the abrasive paste increased.

Ti–Al–V–Nb alloys with the cluster formula, 12[Al–Ti12](AlTi2)+5[Al–Ti14](V,Nb)2Ti, were designed by replacing V with Nb based on the Ti–6Al–4V alloy. Single-track cladding layers and bulk samples of the alloys with Nb contents ranging from 0 to 6.96 wt.% were prepared by laser additive manufacturing to examine their formability, microstructure, and mechanical properties. For single-track cladding layers, the addition of Nb increased the surface roughness slightly and decreased the molten pool height to improve its spreadability. The alloy, Ti–5.96Al–1.94V– 3.54Nb (wt.%), exhibited better geometrical accuracy than the other alloys because its molten pool height was consistent with the spread layer thickness of the powder. The microstructures of the bulk samples contained similar columnar β-phase grains, regardless of Nb content. These grains grew epitaxially from the Ti substrate along the deposition direction, with basket-weave α-phase laths within the columnar grains. The α-phase size increased with increasing Nb contents, but its uniformity decreased. Along the deposition direction, the Vickers hardness increased from the substrate to the surface. The Ti–5.96Al–1.94V–3.54Nb alloy exhibited the highest Vickers hardness regardless of deposition position because of the optimal matching relationship between the α-phase size and its content among the designed alloys.

Publisher Copyright: © 2022 The Author(s) Laser surface texturing (LST) is a powerful technique for creating high quality micro-textured patterns with different shapes and sizes on metallic biomaterials. Textured surfaces may improve the interaction between bone and implant by increasing the surface contact area and thus promoting bone regeneration. The goal of this study was to explore Nd:YAG laser potential for texturing micro-scale pillars with pyramid geometry, with dimensions in a selected range, in a reproducible way. First, the design and texture of grooves were addressed, then proceeding to pillars. Two laser machining and marking strategies were investigated, and the consecutive laser processing strategy and continuous marking mode were selected due to the resultant smoother grooves. Then, a cross-hatched pattern was designed to texture a pillar pattern with targeted dimensions. Given the direct effect of the LST drawing and laser parameters on the texture dimensions, three mathematical models, one for each texture dimension (groove width, pillar width and pillar depth) were developed. These models are accurate tools for predicting the texture dimensions in the selected range and this LST approach was effective on creating well-defined, uniform and equally spaced surface textures on Ti6Al4V parts, in a reproducible way. A combination of drawing and laser parameters was selected for the target dimensions, also considering suitable wettability and roughness for biomedical applications.

PVC membrane was synthesized and its hydrophobicity was investigated by dehydrochlorination in alkaline condition, the addition of tween 60 surfactant and nanoclay. The synthesized membranes were analyzed using the contact angle, FTIR, FE-SEM, EDX, TGA and AFM techniques. High density of membranes was shown by FESEM images. Furthermore, the analysis of AFM revealed that dehydrochlorination can be caused to decrease surface roughness from 117 to 74.9 nm. However, the addition of Tween 60 and nanoclay to membrane increased surface roughness. Results showed that the PVC membrane with pore size of 100 nm is a nanofiltration membrane. The flux of initial membrane was 0.036 mL cm−2 s−1 which increased to 0.058 mL cm−2 s−1 in PVC/nanoClay/Tween 60 membranes. The performance of PVC/nanoClay/Tween 60 membrane was studied in Dead-End membrane systems for removal of BO2 from aqueous solution. Based on the results, dye removal efficiency was 90% under the conditions of 4 bar pressure, room temperature, 20 mg L−1 BO2 concentration, neutral pH and time of 1 h.

Polychlorotrifluoroethylene material is used in industry as a material with excellent insulation, impact resistance and acid and alkali resistance. In this study, we used a magnetic abrasive finishing process with renewable abrasive particles to finish the surface of the polychlorotrifluoroethylene resin plate. Magnetic Abrasive Finishing (MAF) process is a technology that uses flexible magnetic brushes to improve the surface quality of materials. The performance of the magnetic brush is a key factor in surface finishing. In conventional MAF finishing, the number of abrasive particles in the magnetic brush is limited, and the position of the abrasive particles is relatively fixed, which will cause the cutting edge of the abrasive particles to gradually become dull and the finishing efficiency gradually decreases. This paper research the characteristics of the MAF process with renewable abrasive particles. This MAF process has a circulating system that uses a conveyor belt to renew abrasive particles. We use the polychlorotrifluoroethylene resin plate as the experimental processing object to conducted finishing experiment. And the surface roughness of the polychlorotrifluoroethylene resin plate is improved from 315 nm to 32 nm through this process.

This study has been conducted to optimize the dressing parameters to find the minimum surface roughness for internal grinding of hardened SKD11 steel using the Taguchi method. The input parameters used are coarse dressing depth, number of coarse dressing, fine dressing depth, number of fine dressing, non-feeding dressing, and dressing feed speed. The Analysis of Variance (ANOVA) and an analysis of the signal-to-noise (S/N) response are conducted to estimate the significance of each input parameter on the responses. It shows that the number of coarse dressing has the most decisive impact on Ra (88.28%). Furthermore, the discrepancy of the roughness average from the experiments and that from prediction are minor.

In this paper, through a series of grinding experiments with different machining parameters on the surface of the workpiece, the surface roughness under different machining parameters are obtained The surface roughness prediction model is constructed by the response surface method. The effects of feed rate, amplitude, and spindle speed on the surface roughness are analyzed. The results show that the surface quality of ultrasonic-assisted grinding is better than that of conventional grinding. Amplitude has the most prominent effect on the improvement of surface quality, followed by the spindle speed. The feed rate has little effect on the surface roughness. The model can predict 93.71% of the experimental results and the prediction error of the model is lower than 5%.

Cemented carbide has huge applications in industrial production, but its high mechanical properties also increase the difficulty of processing. In this work, ultrasonic vibration-assisted grinding technology is used for the precision manufacturing of cemented carbide. The influence of the dynamic trajectory of the grains on the material removal process is analyzed. The morphology and roughness of the processed surface are measured and studied. It was observed that in the conventional grinding, the blade pattern is obvious with some defects on the surface. While in the ultrasonic vibration-assisted grinding, the material surface is mainly distributed with pits and small protrusions, and there is no obvious blade pattern. According to the roughness test, the roughness of ultrasonic vibration-assisted grinding is better than that of conventional grinding, and the increase in amplitude has a significant effect on the improvement of roughness. When the amplitude increases from 3μm to 9μm, the surface roughness is improved about 38.1%. The research of ultrasonic vibration-assisted grinding should be of great importance for promote the high-efficiency and high-quality processing and special applications of cemented carbide.

This study presents the results of a study on multi-objective optimization of internal cylindrical grinding of hardened SKD11 steel in order to find one objective function which satisfy minimum surface roughness, Ra. By this procedure, an optimum set of dressing parameters such as coarse dressing depth, number of coarse dressing, fine dressing depth, number of fine dressing, non-feeding dressing, and dressing feed speed will be found. Taguchi design methodology is accepted to find the optimum set of dressing parameters which can lead a condition of objective function as above mentioned. ANOVA is conducted based on experimental results to find the significance of each input parameter on the responses. The results reveal that the optimum value of surface roughness is 0.111 μm when using the optimum dressing parameters such as fine dressing depth at level of 2, number of fine dressing at level of 3, number of non-feeding dressing at level of 4, number of coarse dressing at level of 3, coarse dressing depth at level of 2, and dressing feed rate at level of 1.

Targeted at a composite material with a novel Ti-555 high-strength titanium alloy matrix developed using the method of "reinforcement wet grinding-spark plasma sintering-heat treatment", a study is...

Laser polishing, as a novel surface processing technology, has been successfully employed for improving the surface smoothness and geometric accuracy of components for metals, glasses, fibers and c...

This paper experimentally investigates the process of deformation-induced mesoscopic surface roughening in commercially pure aluminum under uniaxial tension. Surface profiles are recorded in selected observation areas at different stages of stretching using a contact profilometer. It is shown that multiscale undulations are formed on the surface from the very beginning of plastic deformation and evolve during stretching. The undulations formed due to the collective displacement of 10–15 grains make the greatest contribution to roughening. A quantitative assessment and comparison of the behavior of mesoscopic undulations are carried out using a dimensionless parameter of the degree of roughness, which is the ratio of profile length to evaluation length, determined for the obtained surface profiles in the studied strain range. A correlation between the roughness degree and local plastic strains is established.

The influence of bias voltage on surface microstructure of TiN films deposited on Ti substrate by multi-arc ion plating was systematically investigated. The TiN films were characterized using X-ray diffraction, scanning electron microscopy and atomic force microscopy. The corrosion resistance was tested by potentiodynamic polarization and electrochemical impedance spectroscopy at 70–80 °C in the simulated PEMFC cathode environment. The results show that the surface microstructure of TiN film depends strongly on the bias voltages. At the bias voltage of −100 V, TiN film shows the optimum surface microstructure with the lowest surface roughness Rz of 0.039 μm tested by AFM and relatively high compactness. The optimized TiN film exhibits excellent corrosion resistance with corrosion current density of 0.87 μA/cm2 in a 0.5 M H2SO4 + 2 ppm HF solution at 80 °C with air and a low interfacial contact resistance (ICR) value of 3.0 mΩ cm2 at a compaction force of 140 N/cm2. These results support TiN as a promising coating material for Ti bipolar plates.

The development of antifouling coating for sensor is desirable because the biofilm can shorten sensor’s life and cause inaccurate reading. In this study, a facile one-pot reaction was used to synthesized ZnO–graphene oxide (GO) (ZnO–GO) nanocomposites. Different amount of ZnO–GO was incorporated in the polydimethylsiloxane (PDMS) matrix respectively though a simple solution mixing method, in order to create PDMS/ZnO–GO nanocomposite (PZGO). The coating was obtained directly by spin coating of PZGO/tetrahydrofuran suspension. The hydrophobicity, surface roughness (Ra), surface free-energy (SFE) and nanoscale structure were investigated as antifouling factors. Antifouling tests were performed using two marine microorganisms, the cyanobacterium Synechococcus sp. Strain PCC 7002 and the diatom Phaeodactylum tricornutum. PZGO0.2 (mass ratio of ZnO–GO to PDMS: 0.2 wt%) displayed excellent antifouling property with 8.5% of Synechococcus sp. Strain PCC 7002 biofilm coverage, while PZGO0.1 (mass ratio of ZnO–GO to PDMS: 0.1 wt%) showed 2.4% P. tricornutum biofilm coverage. The antifouling property of the synthesized PZGO nanocomposite can be attributed to its high Ra and hydrophobicity which was caused by the good dispersion of ZnO–GO in PDMS matrix. This study suggests a potential of PZGO nanocomposite for sensor’s antifouling coating, which could contribute to improve sensor’s durability relating to biofouling in future. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

PurposeThis study aims to investigate the effect of temperature applied at the initial deposition of Aluminium Nitride (AlN) thin-film on a silicon substrate by high-power impulse magnetron sputtering (HiPIMS) technique. Design/methodology/approachHiPIMS system was used to deposit AlN thin film at a low output power of 200 W. The ramping temperature was introduced to substrate from room temperature to maximum 100°Cat the initial deposition of thin-film, and the result was compared to thin-film sputtered with no additional heat. For the heat assistance AlN deposition, the substrate was let to cool down to room temperature for the remaining deposition time. The thin-films were characterized by X-ray diffraction (XRD) and atomic force microscope (AFM) while the MIS Schottky diode characteristic investigated through current-voltage response by a two-point probe method. FindingsThe XRD pattern shows significant improvement of the strong peak of the c-axis (002) preferred orientation of the AlN thin-film. The peak was observed narrowed with temperature assisted where FWHM calculated at 0.35° compared to FWHM of AlN thin film deposited at room temperature at around 0.59°. The degree of crystallinity of bulk thin film was improved by 28% with temperature assisted. The AFM images show significant improvement as low surface roughness achieved at around 0.7 nm for temperature assisted sample compares to 3 nm with no heat applied. Originality/valueThe small amount of heat introduced to the substrate has significantly improved the growth of the c-axis AlN thin film, and this method is favorable in the deposition of the high-quality thin film at the low-temperature process.

The LCMO: Ag0.2 thin film was grown on the tilted LAO substrate by pulsed laser technology. The structural and electrical properties of the thin film were studied with different deposition times. The X-Ray diffraction analysis demonstrated that all film samples showed exhibit mixed growth and have high crystalline quality. The surface morphology of the films was characterized by atomic force microscopy, and the surface roughness of the films decreased as the deposition time increased. Electrical properties tests show that the peak voltages Up of LIV signals of the films reach their maximum at a deposition time of 10 min, while it also having the TCRmax = 18.43%·K−1. The testing results show that the presence of optimal film thickness can enhance the anisotropic Seebeck coefficient of the film, which in turn improves the film properties.

The complex problem of inorganic scale formation on heat transfer surfaces is of substantial importance for industrial and domestic systems. Formation of mineral scale, particularly calcium carbonate, has long been a concern in domestic appliances such as boilers, steamers and washing machines. Here, the formation of solid inorganic deposits was studied on solid surfaces and in the bulk solution as a result of evaporation of natural potable water. Scale precipitation rates were evaluated for metallic samples for various bulk temperatures, surface roughness values and as a function of time. The morphology of crystals from both surface and solution was evaluated. The concentration of calcium ions was evaluated using Atomic Absorption Spectrophotometry (AAS), in order to investigate the kinetics of the precipitation reaction. The microstructure and morphology of deposits on the surface were analysed using Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The present work has demonstrated that fouling deposition rates increase as the evaporation process proceeds as expected. The nature of the material and the surface roughness both affect surface deposition kinetics. The complex relationship between the saturation ratio (as the bulk solution shows precipitation) and the kinetics of bulk and surface precipitation/deposition is demonstrated. The prevailing crystalline form of calcium carbonate as detected by SEM and XRD is aragonite. However, the polymorphic composition of surface deposition and the bulk precipitate is influenced by temperature.

This work presents an in-situ technique to quantify the layer-by-layer roughness of thin films and heterostructures by measuring the spectral profile of the reflection high-energy electron diffraction (RHEED). The characteristic features of the diffraction spot, including the vertical to lateral size ratio c/b and the asymmetrical ratio c1/c2 along the vertical direction, are found to be quantitatively dependent on the surface roughness. The quantitative relationships between them are established and discussed for different incident angles of high-energy electrons. As an example, the surface roughnesses of LaCoO3 films grown at different temperatures are obtained using such an in-situ technique, which are confirmed by the ex-situ atomic force microscopy. Moreover, the in-situ measured layer-by-layer roughness oscillations of two LaCoO3 films are demonstrated, revealing drastically different information from the intensity oscillations. The experiments assisted with the in-situ technique demonstrate an outstanding high resolution down to ∼ 0.1 A. Therefore, the new quantitative RHEED technique with real-time feedbacks significantly escalates the thin film synthesis efficiency, especially for achieving atomically smooth surfaces and interfaces. It opens up new prospects for future generations of thin film growth, such as the artificial intelligence-assisted thin film growth.

The rational optimization of plasmonic property of metal nanocrystals by manipulating the structure and morphology is crucial for the plasmon-enhanced application and has always been an urgent issue. Herein, Au nanorods with tunable surface roughness are prepared by growing PbS, overgrowing Au, and dissolving PbS nanoparticles on the basis of smooth Au nanorods. The transverse plasmon resonance of Au nanorods is notably improved due to plasmon coupling between Au nanorods and the surface-modified Au nanoparticles, resulting in the strong and full-spectrum light absorption. Numerical simulations demonstrate that the surface-rough Au nanorods have abundant and full-surround hotspots coming from surface particle-particle plasmon coupling between ultrasmall nanogaps, sharp tips, and uneven areas on Au nanorods. With these characters, the surface-roughness-adjustable Au nanorods possess high tunability and enhancement of surface-enhanced Raman scattering (SERS) detection of Rhodamine B and significantly improved photothermal conversion efficiency. Au nanorods with the largest surface roughness have the highest Raman enhancement factor both at 532 and 785 nm laser excitation. Meanwhile, photothermal conversion experiments under near-infrared (808 nm) and simulated sunlight irradiation confirm that the Au nanorods with rough surface have prominent photothermal conversion efficiency and can be regarded as promising candidates for photothermal therapy and solar-driven water evaporation.

Purpose The purpose of this paper is to enhance the efficiency of the LED by introducing three-step magnesium (Mg) doping profile. Attention was paid to the effects of the Mg doping concentration of the first p-GaN layer (i.e. layer close to the active region). Attention was paid to the effects of the Mg doping concentration of the first p-GaN layer (i.e. layer close to the active region). Design/methodology/approach Indium gallium nitride (InGaN)–based light-emitting diode (LED) was grown on a 4-inch c-plane patterned sapphire substrate using metal organic chemical vapor deposition. The Cp2Mg flow rates for the second and third p-GaN layers were set at 50 sccm and 325 sccm, respectively. For the first p-GaN layer, the Cp2Mg flow rate varied from 150 sccm to 300 sccm to achieve different Mg dopant concentrations. Findings The full width at half maximum (FWHM) for the GaN (102) plane increases with increasing Cp2Mg flow rate. FWHM for the sample with 150, 250 and 300 sccm Cp2Mg flow rates was 233 arcsec, 236 arcsec and 245 arcsec, respectively. This result indicates that the edge and mixed dislocations in the p-GaN layer were increased with increasing Cp2Mg flow rate. Atomic force microscopy (AFM) results reveal that the sample grown with 300 sccm exhibits the highest surface roughness, followed by 150 sccm and 250 sccm. The surface roughness of these samples is 2.40 nm, 2.12 nm and 2.08 nm, respectively. Simultaneously, the photoluminescence (PL) spectrum of the 250 sccm sample shows the highest band edge intensity over the yellow band ratio compared to that of other samples. The light output power measurements found that the sample with 250 sccm exhibits high output power because of sufficient hole injection toward the active region. Originality/value Through this study, the three steps of the Mg profile on the p-GaN layer were proposed to show high-efficiency InGaN-based LED. The optimal Mg concentration was studied on the first p-GaN layer (i.e. layer close to active region) to improve the LED performance by varying the Cp2Mg flow rate. This finding was in line with the result of PL and AFM results when the samples with 250 sccm have the highest Mg acceptor and good surface quality of the p-GaN layer. It can be deduced that the first p-GaN layer doping has a significant effect on the crystalline quality, surface roughness and light emission properties of the LED epi structure.

A numerical study was performed on the embankment weir overflows with various surface roughness and tailwater submergence, to better understand the effects of weir roughness on discharge performances under the free and submerged conditions. The variation of flow regime is captured, from the free overflow, submerged hydraulic jump, to surface flow with increasing tailwater depth. A roughness factor is introduced to reflect the reduction in discharge caused by weir roughness. The roughness factor decreases with the roughness height, and it also depends on the tailwater depth, highlighting various relations of the roughness factor with the roughness height between different flow regimes, which is linear for the free overflow and submerged hydraulic jump while exponential for the surface flow. Accordingly, the effects of weir roughness on overflow discharge appear nonnegligible for the significant roughness height and the surface flow regime occurring under considerable tailwater submergence. The established empirical expressions of discharge coefficient and submergence and roughness factors make it possible to predict the discharge over embankment weirs considering both tailwater submergence and surface roughness.

Surface roughness is an important factor that affects the wetting of molten metal on ceramics. The effect of surface roughness of the alumina substrate on the contact angle, contact diameter, drop height and surface tension of molten lead was investigated in the temperature range of 923–1123 K. The microstructure of the lead/substrate interface was observed by SEM. The surface free energy of alumina substrates was calculated by the geometrical average method. When the surface roughness of the substrate increased from 0.092 to 2.23 μm, the surface free energy increased gradually, ranging from 13.356 to 39.998 mJ/m2. The contact diameter of lead droplets decreased from 9.111 to 7.19 mm. The lead drop height increased from 3.41 to 3.85 mm. The contact angle increased from 113.05° to 137.15°. Moreover, the surface depression of the alumina substrate was filled with lead, and no obvious change was observed. The results demonstrated that the wetting of lead drop on alumina substrates was consistent with the Wenzel state.

Machines operating in aqueous environments may be subjected to cavitation damage during operation. This study aims to evaluate the cavitation resistance of WC-10Co4Cr and WC-20CrC-7Ni coatings under cavitation erosion conditions with additional electrochemical effects. The coatings were deposited on AISI 1040 steel substrates using a high velocity air fuel thermal spray process. The microstructure of the coatings was observed by a scanning electron microscope, while their phase composition was analyzed using an energy-dispersive microanalysis system. In addition, the microhardness of the coatings and substrate was measured, and the surface topography of the eroded surface layers was observed using a 3D optical profilometer. The results revealed that the cavitation resistance of the WC-20CrC-7Ni coatings was better than that of the WC-10Co4Cr coatings. The observation of the structure and surface topography made it possible to identity the reasons for the differences between the cavitation resistance of both coatings: The WC-20CrC-7Ni coatings had a finer grain structure, lower pore density, and lower as-sprayed surface roughness. These differences, along with the presence of a high Cr and Ni content in the feedstock powder, that increased the coating corrosion resistance, contributed to improving the cavitation resistance and reducing the material loss of the WC-20CrC-7Ni coatings.

Static contact angle hysteresis determines droplet stickiness on surfaces, and is widely attributed to surface roughness and chemical contamination. In the latter case, chemical defects create free-energy barriers that prevent the contact line motion. Electrowetting studies have demonstrated the similar ability of electric fields to alter the surface free-energy landscape. Yet, the increase of apparent static contact angle hysteresis by electric fields remains unseen. Here, we report the observation of electrowetting hysteresis on micro-striped electrodes. Unlike most experiments with stripes, the droplet spreading on the substrate is experimentally found to be isotropic, which allows deriving a simple theoretical model of the contact angle hysteresis depending the applied voltage. This electrowetting hysteresis enables the continuous and dynamic control of contact angle hysteresis, not only for fundamental studies but also to manufacture sticky-on-demand surfaces for sample collection. Wetting of surfaces can be affected by surface roughness, presence of surface chemical defects, or by electric fields. Here, the authors perform electrowetting experiments on microstriped electrodes and show that the droplet’s static contact angle hysteresis can be controlled by an inhomogeneous electric field while remaining isotropic, as does the droplet contact radius.

Silicone rubber nanocomposites were prepared using 1, 3, 5, and 10 wt% of alumina nanofiller. Corona inception voltage (CIV) due to water droplets was measured using fluorescence technique, and it has decreased for alumina-added silicone rubber nanocomposites and with corona-aged samples. The effect of the corona discharges on the surface morphology characteristics of the nanocomposites was analyzed by measuring contact angle, surface profile measurement using atomic force microscopy (AFM), and characterized by adopting multiresolution signal decomposition (MRSD) technique. The addition of the alumina nanofiller suppressed the surface roughness for the corona-aged nanocomposites and 5-wt% sample observed to have the lowest surface roughness values. Recovery of the surface roughness caused by corona discharges was analyzed at different time intervals, and it was observed that alumina nanoparticle-added silicone rubber showed an incremental reduction in the roughness recovery rate. The laser-induced breakdown spectroscopy (LIBS) technique was adopted to analyze the nanocomposites after the corona aging, and further plasma temperature was evaluated at different recovery times. The addition of an alumina nanofiller increased the plasma temperature, and 5-wt% samples have the lowest plasma temperature recovery rate after corona aging. The analysis of the study indicates that the corona-aged silicone rubber specimen surface properties recover in 8 h of resting time period.

We have developed a fabrication technology for superconducting integrated circuits with Nb-based Josephson junctions. The standard fabrication process with 10 mask levels includes 3 Nb superconducting layers and a Mo resistor layer. The influence of deposition parameters on film stress, electrical properties, and surface roughness were studied systematically. High quality Nb, Al, Mo, and SiO2 films were successfully deposited for the subsequent fabrication of circuits. The circuit fabrication started with the fabrication of Mo resistors with a target sheet resistance R sh of 2 Ω, followed by the deposition of Nb/Al-AlO x /Nb trilayer Josephson-junction. The target critical current density J c was set at 6 kA/cm2. Small-scale circuits such as our standard library cells have been successfully fabricated and tested, confirming the capability of our fabrication technology for superconducting integrated circuits.

This article presents a variation-aware exponential matrix–rational approximation (EM-RA) model for the signal integrity analysis in single-walled carbon nanotube (SWCNT) bundle and hybrid copper-CNT (Cu-CNT) on-chip interconnects. The variations include temperature (300–500 K) only, and temperature (300–500 K) and dielectric surface roughness (10–180 pm) both. The transient analysis is carried out for the signal integrity parameters, crosstalk and propagation delay, estimation using the proposed EM-RA model. The results obtained using the proposed model are compared with the industry-level simulation program with an integrated circuit emphasis (SPICE) simulator. The comparison shows excellent agreement for the results with less than 1% error. The proposed model is also compared for the computational time complexity. It is observed that a speed-up factor of 74.24 and 48.35 is attained using the proposed temperature-parameterized model during the analysis of coupled-two and coupled-three interconnect lines, respectively. The speed-up further increases to 485.41 and 378.35 for coupled-two and coupled-three lines, respectively, when the temperature and dielectric surface roughness parametrized EM-RA model is used. This computational CPU time expense efficiency and the accuracy of the proposed model in comparison to the HSPICE simulator ensures immense possibility regarding its implementation in computer-aided design (CAD) tools for carrying out the transient analysis of SWCNT bundle and Cu-CNT interconnect lines. Encouraging results for the eye-diagram analysis reports 95.54% and 99.37% of the eye height and eye width for the SWCNT network, and 99.77% and 99.96% of the eye height and eye width for the Cu-CNT.