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The effect of nickel silicide on the friction properties of Cu-based wet sintered friction materials was investigated. The microstructure and mechanical properties of nickel silicide added Cu-based wet sintered friction materials were examined. Nickel silicide was prepared by mechanically alloying Ni and Si powder. Three types of Cu-based wet sintered friction materials with different nickel silicide contents (0 wt%, 5 wt%, 10 wt%) were fabricated by the powder metallurgy route. The phase transformation of Ni2Si to Ni31Si12 was observed in nickel silicide after a sintering process. The friction coefficient and wear rate decreased with increasing nickel silicide content. The wear scar changed from ploughing to micro-cutting with increasing nickel silicide content. As a result, it is suggested that nickel silicide can be used as a friction modifier when added to Cu-based wet sintered friction materials.

The effect of electric current on the refinement of pure aluminum during solidification was investigated based on microstructural observations and numerical simulations. Coarse columnar grains are observed without the application of direct current (DC off), while equiaxed grains clearly exist under the application of electric current during solidification; the area fraction of the equiaxed zone increased up to 66% under electric current, whereas it is negligible in DC off condition. Also, grain size decreased drastically to 221 μm under electric current compared to that of several mm in DC off condition. The grain refinement was affected by the electrical conditions such as the intensity and duration of applied electric current. The flow in liquid aluminum was observed experimentally from the homogenization of the cooling curves measured at different heights and the oscillations in the cooling curves, when electric current was applied during solidification. Through numerical analysis, it was found that the circulating flow of liquid aluminum was developed by the Lorentz force induced by a combination of the electric current density field and magnetic flux density field under electric current. Moreover, the circulating flow could affect grain refinement by providing additional nuclei through dendrite fragmentation. However, under extreme conditions of relatively high electrical energy, the refining effect could disappear because of the retardation of solidification or remelting of nuclei, induced by the Joule heating effect. This study proves that electric current plays an important role in the control of solidification structure.

The workability of Al–xMg alloys with a high Mg content (Al–6Mg, Al–8Mg, Al–9Mg) was evaluated by investigating the microstructure and processing map. Hot torsion tests were conducted in the range of 350–500 °C between 0.1 and 1 s−1. Constitutive equations were derived from various effective stress–strain curves, and the thermal activation energies for deformation obtained were 171 kJ/mol at Al–6Mg, 195 kJ/mol at Al–8Mg, and 220 kJ/mol at Al–9Mg. In the case of the processing map, the instability region, which widened with increasing Mg content, was due mainly to the influence of the Mg solute, which activated grain boundary cracking and flow localization.

This study reports the effects of NiO nanoparticle (NP) size on the sensing performance of NiO NP-decorated SnO2 nanorods (NRs). NiO NP-decorated SnO2 NRs were synthesized using a two-step process: 1) thermal evaporation of tin powders in an oxidizing atmosphere based on the vapor-liquid-solid growth mechanism and 2) solvothermal decoration of SnO2 NRs with NiO NPs. X-ray diffraction and transmission electron microscopy analyses revealed that both the SnO2 NRs and the NiO NPs were polycrystalline. Scanning electron microscopy images showed that the diameters of the NRs ranged from 100 to 200 nm and that those of the small and the large NiO NPs ranged from 20 to 30 nm and from 80 to 180 nm, respectively. The small NiO NP-decorated SnO2 NRs showed stronger response to NO2 than did the large NiO NP-decorated SnO2 NRs over the concentration range of 0.5–100 ppm. Decoration of SnO2 NRs with small NiO NPs resulted in enhanced sensing performance whereas decoration of SnO2 NRs with large NiO NPs deteriorated the sensing performance. The superior NO2 gas sensing performance of the small NiO NP-decorated SnO2 NR sensor as compared to that of the large NiO NP-decorated SnO2 NR sensor was attributed to a higher ratio of n-SnO2 to p-NiO and a higher number of p-n heterojunctions for the same volume of NiO in the former than in the latter. In addition, the small NiO NP-decorated SnO2 NR sensors showed selectivity toward NO2 against other competing gases such as SO2, CO2, CO, H2, C7H8 and C6H6.

In2O3/SnO2 composite nanoparticles (NPs) were synthesized by a hydrothermal method. Fringes and spotty patterns were observed in high-resolution TEM images and corresponding selected area electron diffraction pattern, respectively, suggesting the nanoparticles were single crystals. X-ray diffraction results revealed that the In2O3/SnO2 composite NP sensor consisted of three phases: In2O3, SnO2 and In2Sn2O7−x (indium tin oxide: ITO). Energy-dispersive X-ray spectrum of the 9:1 In2O3/SnO2 composite NPs showed the atomic ratio of In2O3 to SnO2 was close to 9:1. The response of the chemiresistive sensor to CO was 9.2, which is within the highest 15% among the response values reported for the past 10 years. The ITO NP-based gas sensor is selective toward CO against other reducing gases such as toluene, acetone and benzene. The enhanced response of the 9:1 In2O3/SnO2 composite NP sensor to CO compared to the pure In2O3 NP sensor can be explained mainly by the stronger resistance modulation at the In2O3/SnO2 junctions.

Pores and cracks are known as the main defects in metal additive manufacturing (MAM), including directed energy deposition(DED). A gaseous fume is often produced by laser flash (instantaneous high temperature) during laser processing, which may cause various defects such as porosity, lack of fusion, inhomogeneity, low flowability and composition change, either. However the cause and harmful effects of fume generation in DED are known little. In laser processing, especially laser welding, many studies have been conducted on the prevention of fume because it generates defects that hinder uniform reactions between the laser beam and the materials. Generally, the fume occurs with easily vaporizing low melting point components or sensitive oxidizing elements. Unsuitable conditions are also known to have an effect, including laser power, travel speed, powder feed rate and shielding gas supply. Practically, there are many more fume generating factors in the DED process, and the lack of understanding requires a lot of trial and error. In this article the laser-related and weld metallurgy literatures were reviewed, focusing on the prevention of fume in powder DED. The causes of the fume, were explained to result from the stages of cavitation bubbles generated by the laser induced plasma and the nanoparticles released. Additionally, the effects of alloying components and environmental conditions for fume generation in the DED process were investigated, and suggestions are proposed to prevent fume.

Strain distribution in plane-strained (rolling) and simple-sheared (torsion) Al–Mg alloy has been estimated using both X-ray line profile analysis and electron backscatter technique. The strain analyses under unified texture distribution by orientation rotation showed that torsion has relatively homogeneous strain distribution regardless of texture component in contrast to inhomogeneous strain in rolling. In addition, annealing texture of torsion has more random texture than inhomogeneous rolling texture. Lower texture difference index in annealed torsion specimens suggest homogeneous strain distribution in simple shear has a higher resistance to strain-induced boundary migration, which has been known to be main reason for strong development of ND||〈100〉 component during annealing of rolled Al sheet.

Despite the industrial significance of grain boundary serration for improving creep resistance and retarding crack propagation, the mechanism of grain boundary serration during hot deformation is still unclear. The results of several studies indicated that increased inhomogeneity of the stored energy under high-stress deformation suppressed grain boundary serration. Thus, traditional strain-induced boundary migration, in which the stored energy difference between adjacent grains acts as the driving force for grain boundary serration, must be modified for hot deformation. The experimental results of this study suggested that dissociated grain boundary dislocations from lattice dislocations, rather than the elastic energy of the lattice dislocations, cause the nucleation of serrated grain boundaries. Grain boundary sliding on the serrated grain boundary asymmetrically generated an elastic energy field and an accommodated serrated grain boundary. The presence of an elastic energy field was predicted by dislocation climbing and statically distributed dislocations near the elastic energy field. Since the asymmetrically deformed serrated grain boundary exhibited sub-migration behavior in the elastic energy field, it was concluded that the applied shear stress (applied by grain boundary sliding) on the serrated grain boundary dominated the growth of serrated grain boundaries until dynamic recrystallization occurred.

Yttria-stabilized zirconia (YSZ) and Al₂O₃ multilayer coatings were fabricated by plasma spraying. Thermal conductivity and thermal shock test were investigated to find out the thermal properties of the coating layer and the surface of the crack. Thermal conductivity was investigated using laser flash method and thermal shock were measured by water quenching method. Furthermore, the factors influencing thermal properties of these coatings were analyzed in detail. Multilayer coatings have imperfect interfaces. At an imperfect interface, the heat transfer coefficient was close to zero, indicating a low thermal conductivity. Multilayer coatings increase thermal shock resistance. This is because ZrO₂ phases transformation from tetragonal to monoclinic occurring to the cooling process, resulting in microcracks due to volume expansion. The crack generated at this time dispersed and absorbed the thermal shock, so that it exhibited excellent thermal shock resistance.

The methods of design of experiment (DOE), analysis of variance (ANOVA) and response surface (RS) are used to study the effect of heat treatment on the microstructure and mechanical properties of a novel AlSi11MgMn pressure-cast alloy with an addition of Al2Ca. After the high-pressure casting, the specimens are solution treated at 490°C for 15 min and quenched in cold water. After the solution treatment, the morphology of the eutectic silicon changes, the elongation increases, and the yield strength and the ultimate strength decrease. The effect of the aging temperature and time on the tensile mechanical properties is studied by 4 × 4 full factorial design of experiment. The response surface is plotted for the ultimate and yield strengths and for the elongation; three equations predicting satisfactorily the mechanical properties of the alloy as a function of the aging temperature and time are derived.

A new approach method has been studied for the efficient and accurate prediction of high-entropy alloys (HEAs) properties. The artificial neural network (ANN) algorithm was employed to predict the mechanical properties such as yield strength, microstructure, and elongation of the alloy by training from the mole fraction and post-process information that has an influence on the mechanical properties. The mean error rate of prediction for the yield strength was 19.6%. Microstructure predictions were consistent for all test data. On the other hand, the ANN model trained only with mole fraction data had a yield strength prediction error of 33.9%. Omission of post-process data caused a decrease in the accuracy. In addition, the prediction was performed with the lasso regression model in the same way. The mean error rate of the lasso model trained with only a mole fraction was 26.1%. The lasso model trained with a mole fraction and post-process data had a yield strength prediction error of 31.1%. The linear regression equation showed limitations, as the accuracy decreased as the number of independent variables increased. As there are more variables affecting metal properties, the ANN approach is more advantageous, and the more data there are, the more accuracy increases, making it possible to design HEAs alloys that are simpler and more efficient than conventional methods. This approach predicted HEAs properties using only mole fraction and post-processing information, without the need to use conventional physicochemical theories or perform derived complex calculations.

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.

Two types of CaO and Pt nanoparticles (NPs)-decorated SnO2 nanorods (NRs), SnO2 NRs co-decorated with a simple mixture of Pt and CaO NPs (CaO-Pt@SnO2) and SnO2 NRs decorated with Pt-decorated CaO NPs (Pt@CaO@SnO2), were fabricated and their NO2 sensing properties were examined. CaO-Pt@SnO2 was prepared by the decoration of SnO2 NRs with CaO NPs first and then Pt NPs, whereas Pt@CaO@SnO2 was prepared by the decoration of CaO NPs with Pt NPs and then the decoration of SnO2 NRs with the Pt-decorated CaO NPs. Pt@CaO@SnO2 showed significantly better NO2 sensing properties than CaO-Pt@SnO2. This result can be explained through a combination of electronic and chemical sensing in the mechanisms, but the chemical mechanism is dominant. In the Pt@CaO@SnO2 sample, Pt NPs exist only on the surfaces of the CaO NPs. The CaO NPs tend to adsorb H2O molecules environment because of their hygroscopic property and change to Ca(OH)2. The Ca(OH)2 molecules dissociate into CaO at 300 °C. Pt NPs on the CaO NPs catalyze the dissociation of Ca(OH)2 molecules, which enhances the gas sensing properties of the sample. In contrast, the dissociation of Ca(OH)2 molecules is not catalyzed by Pt NPs in the CaO-Pt@SnO2 sample.

Lotus-type porous copper was fabricated by a centrifugal casting. The long cylindrical pores aligned along single direction was formed during unidirectional solidification in a hydrogen atmosphere under a centrifugal force. The relationship between processing parameters and pore characteristics in centrifugal casting was investigated in detail. Porosity and average pore diameter increased with increasing distance from bottom of ingot and rotational velocity. The processing parameter in centrifugal casing affected the pressure on liquid/solid interface and the solidification rate during unidirectional solidification. It is concluded that an appropriate pore characteristics of lotus-type porous copper can be obtained by control of processing parameters in the centrifugal casting.

The precipitate transformation mechanism of Al8Mn4Ca and its effect on mechanical properties of CaO-added AZ31 were investigated. Microstructural characterization showed that precipitate transformation occurred by dissolution of the C15 (Al2Ca) phase during solution heat treatment. Then, dissolved Al and Ca solutes have formed segregation layer near metastable τ (Al11Mn14 and Al8Mn11) which leads phase transformation. Depending on different diffusion kinetics of Al and Ca solutes, formation of Al8Mn4Ca or γ2 (Al8Mn5) was determined by distribution of C15 near τ. To this end, complex layered particle structures were frequently found. The precipitate transformation affected mechanical properties of the alloy. Due to fragment behavior during phase transformation and irreversibility of Al8Mn4Ca, duration of solution heat treatment affects hardening behavior. Precise control over the solution heat treatment process is necessary to obtain optimal properties in Ca-bearing Mg-Al-Mn alloys because of the unique conditions required for the formation of Al8Mn4Ca.

In this study, the changes in the microstructural characteristics and mechanical properties of A356 alloys as a function of Mn content and cast thickness were evaluated using structural analysis and tensile tests. Five different A356+x%Mn alloys were prepared by casting in molds of different thicknesses followed by solid solution treatment at 813 K for 195 min and aging treatment at 423 K for 120 min. It was confirmed that the secondary dendrite arm spacing (SDAS) increased with increasing thickness of the cast sample, whilst, for a given thickness, the addition of small amounts of Mn resulted in a decrease of the SDAS. Mn contents of 0.05-0.15% resulted in ~7-9% improvements in the spheroid ratio of the primary Si particles compared to that of the commercial A356 alloy. Further, the spheroid ratio of the primary Si particles obtained in the thin cast samples were higher than that obtained in the thick cast samples. In particular, the addition of small amounts of Mn was also effective in suppressing the formation of the needle-like beta Al-Fe-Si intermetallic compound. The yield and tensile strengths of the thinner cast samples were higher than those of the thicker cast samples. Finally, Mn contents of 0.05-0.15% resulted in enhanced yield and tensile strengths, but Mn content ≥0.1% resulted in decreased elongation.

Higher manganese silicide is generally used in thermoelectric devices between 700 K and 900 K. MnSi1.73Al0.005 samples were fabricated by two continuous solid-state reactions followed by hot pressing because the electrical conductivity of all the samples is strongly dependent on Al doping, showing superior thermoelectric performance to the as-synthesized higher manganese silicide. The solid-state-reaction was performed at 1173 K for 6 hours. The effects of the sintering temperature were examined by sintering at three different temperatures: 1273 K, 1323 K and 1373 K. For the surface, microstructural, and electrical properties, scanning electron microscopy, X-ray diffraction, and a series of electric conductivity, Seebeck coefficient, and thermal conductivity analyses were conducted, respectively. As a result, the optimal process temperature for Al-doped higher manganese silicide using a hot-press technique was determined.

Intrinsic Cu- and Ni-added Cu electrodes were prepared to study Sn-3Ag-0.5Cu lead-free solder joints. Our work focused on three categories: (1) formation and role of intermetallic compounds, (2) structural and compositional change of intermetallic compounds due to thermal aging effects, and (3) mechanical bonding strength of solder joints. A series of SEM, EDX, and bonding test analyses were performed on two electrode types to study joint morphologies, the types of intermetallic compounds formed, and bonding strengths, respectively. As a result, after heat treatments at 150 °C for 10 h, 100 h, and 300 h, Cu6Sn5 and (Ni, Cu)₃Sn₄ were obtained at the interfaces of the intrinsic Cu electrode and the Ni-added Cu electrode, respectively. In the Ni-added Cu electrode samples, the growth rate of the intermetallic compounds was reduced, but the mechanical bonding strength had a higher value compared to that of the intrinsic Cu electrode. The bonding characteristics under different heat treatment conditions are also discussed.

Optimum processing conditions were obtained by evaluating the hot working behavior of commercially pure Ti using hot torsion tests. Hot torsion tests were conducted at temperatures ranging from 800 °C-1000 °C and strain rates ranging from 0.1-10 s-1. The flow curves show that the peak stress increases as the temperature decreases and the strain rate increases. The optimum processing conditions were derived by comparing the processing and activation energy maps. The microstructure was characterized based on various regions of the processing map. The activation energy for plastic deformation was obtained using the constitutive equation. The activation energy differs depending on the constituent phases.

Owing to the energy and environmental issues, energy recovery technologies attract an increasing interest. Thermoelectric power generation is a recycling technology, which directly converts heat energy into electric energy by reusing waste heat. In this study, n-type Bi₂Te2.7Se0.3 thermoelectric materials doped with Cu were fabricated by hot pressing. The Bi-Te system has excellent thermoelectric properties in the middle- and low-temperature ranges; when a certain amount of Cu dopant is added, the thermoelectric properties are improved. The thermoelectric properties of the samples doped with Cu were compared with those of the intrinsic Bi-Te-based sample without Cu doping. In addition, the effects of the Cu concentration on the thermoelectric-material structures were investigated.

Hot torsion tests were carried out on an AA6005 modified with CaO-added Mg to study its hot deformation behavior. The flow curves indicated that the failure strain of the modified alloy was greater than that of the conventional alloy at low temperature and all strain rates employed in this study. The constitutive analysis was conducted on the effective stress–effective strain data, and the derived activation energy for hot deformation of the modified alloy was lower than that of the conventional alloy. The processing maps were established at various strains, and the power dissipation efficiency increased as the strain increased. The gap between contour lines decreased as the strain increased, indicating that the power dissipation efficiency became more sensitive to the strain. The optimum deformation conditions were determined by comparing the power dissipation efficiency in the processing maps. However, the power dissipation efficiency of the modified alloy was greater than that of the conventional alloy. The observed microstructure demonstrated that the lower activation energy, greater failure strain, and higher power dissipation efficiency were primarily attributed to the different states in the distribution of second phase particles caused by the use of CaO-added Mg.

The hot deformation behavior of advanced reduced-activation alloy (ARAA) was investigated using hot torsion tests. The flow stress decreased as deformation temperature increased and as strain rate decreased. The flow behavior demonstrated the typical dynamic recrystallization (DRX). Based on the constitutive analysis of peak stress, the activation energy for hot deformation was found to be 330.3 kJ mol−1. Peak stress was analyzed as a function of the Zener–Hollomon parameter, and calculated and experimental values were in good agreement. A DRX kinetic model for ARAA was derived with deformation conditions based on the Avrami-type model. It was confirmed that the volume fraction of dynamically recrystallized grains increased as deformation temperature increased and as strain rate decreased. The necklace structure and grain boundary bulging were observed in the deformed microstructure of ARAA. The suggested DRX mechanism for ARAA during hot working is discontinuous DRX.

The controlling alloying elements and deformation parameters are significant factors of the plastic deformation of Mg alloys due to their low formability and difficult-to-control texture. In this study, we investigated the effect of both CaO addition and the strain rate on the texture evolution and flow behavior of AZ31 alloys by carrying out hot torsion. The dislocation components of the deformed AZ31 alloys were evaluated using X-ray line profile analysis (XLPA). The XLPA results showed that the strain rate variation significantly affected the dislocation components and dislocation density of the alloys while CaO addition has only dislocation density effect. According to the results, weaken texture evolution by CaO addition is based on not variation of slip modes but grain boundary mobility. Also, it was determined that high strain rate deformation affect texture evolution by fortifying -type slip mode.

A hot compression test of new Al-6Mg and Al-8Mg alloys was conducted to understand the dynamic recrystallization (DRX) behavior by Mg contents. To investigate the hot workability of Al-Mg with high Mg contents, the hot deformation behavior of Al-6Mg and Al-8Mg alloys was analyzed by a hot compression test in the temperature range of 300–450 °C, and the strain rate range of 10−3–100/s. Subsequently, high-temperature deformation behavior was investigated through the processing map and microstructure observation. In this study, the results have shown that, as the Mg contents increase, the maximum and yield strength increase while rapid flow softening after the peak strain has been observed due to accelerated dynamic recrystallization (DRX). Finally, the increase of Mg contents affects an increase of heat dissipation efficiency to be an indicator of regular deformation.

Directed energy deposition (DED), a type of additive manufacturing (AM) is a process that enables high-speed deposition using laser technology. The application of DED extends not only to 3D printing, but also to the 2D surface modification by direct laser-deposition dissimilar materials with a sub-millimeter thickness. One of the reasons why DED has not been widely applied in the industry is the low velocity with a few m/min, but thin-DED has been developed to the extent that it can be over 100 m/min in roller deposition. The remaining task is to improve quality by reducing defects. Thus far, defect studies on AM, including DED, have focused mostly on preventing pores and crack defects that reduce fatigue strength. However, evaporation products, fumes, and spatters, were often neglected despite being one of the main causes of porosity and defects. In high-quality metal deposition, the problems caused by evaporation products are difficult to solve, but they have not yet caught the attention of metallurgists and physicists. This review examines the effect of the laser, material, and process parameters on the evaporation products to help obtain a high-quality metal film layer in thin-DED.

In this study, the characteristics of commercially pure titanium (hereinafter referred as CP-Ti)/Steel joints, brazed with Zr–Ti–Ni amorphous filler metal were analyzed. The effects of brazing temperature and time on the microstructure and joining strength of the CP-Ti/Steel joints were investigated. It was observed that Ti diffused into stainless steel substrate formed a brittle reaction zone, which contained intermetallic compounds, such as τ (Ti5Cr7Fe17), (Fe, –Ni)Ti, and FeTi, observed at the joint interface. As the brazing temperature and time increased, the width of the reaction layer in the joint was observed to increase. To suppress the oxidation of the substrates, the experiment was conducted at a cooling and heating speed of 100 °C/min, under a vacuum of 5×10−5 torr. The joining strength was observed to be significantly affected by the brazing conditions, such as temperature and duration time. The shear strength test showed that the strength increased for 15 min and then sharply decreased. This was attributed to the formation of brittle intermetallic compounds, like (Fe, Ni)Ti. The joint brazed at 880 °C for 15 min showed the maximum joining strength, of 216 MPa.

Commercial vehicle pistons should have low thermal expansion and should be able to withstand deformation or mechanical stress. Aluminum alloys are suitable for pistons due to their light weight. However, as aluminum alloys have low strength and friction resistance, cast iron is added through the dipping process in order to increase the quality of pistons. However, the dipping process leads to defects such as defective bonding, void formation, and formation of an oxidation film at the junctions of the two materials due to differences in their properties, which adversely affects the impact resistance and mechanical strength of the product. A theoretical study on the metallurgical bond between the aluminum alloy and the cast iron insert in the piston was conducted to investigate the cause of the defects. The microstructure of the intermetallic bonding layer was observed using scanning electron microscopy and electron dispersive spectroscopy. In this study, defects were found in non-bonding and oxide films and several phases were generated corresponding to different parameters. It was found that processing time and temperature were the main causes of these defects.

The effects of laser energy density on microstructural, mechanical properties, and chemical composition of stainless steel 316 L (SUS316L) parts fabricated by selective laser melting (SLM) technology were studied. Total 36 specimens were fabricated under the range from 1.3 to 46.7 J/mm3. The process conditions to achieve over 99.5% ± 0.1% relative planar density were obtained, and the mechanism of tunable mechanical properties was investigated by understanding the correlation between the microstructure and chemical composition according to the energy density. As the energy density increased, tensile properties were decreased with grain growth and the concentrations of light elements were increased by accelerating dissolution. As the concentrations of light elements increased, the mechanism of destructive behavior changed from ductile fracture to brittle fracture and it caused that the hardness was improved. Consequently, it was necessary to control the energy density from 9.34 to 23.98 J/mm3 in order to fabricate SUS316L parts of high strength and high elongation characteristics by SLM method.

In this work, we prepared spinel-type NiCo2O4 (NCO) nanopowders as a low-cost and sensitive electrochemical sensor for nonenzymatic glucose detection. A facile and simple chemical bath method to synthesize the NCO nanopowders is demonstrated. The effect of pH and annealing temperature on the formation mechanism of NCO nanoparticles was systematically investigated. Our studies show that different pHs of the precursor solution during synthesis result in different intermediate phases and relating chemical reactions for the formation of NCO nanoparticles. Different morphologies of the NCO depending on pHs are also discussed based on the mechanism of growth. Electrochemical performance of the prepared NCO was characterized towards glucose, which reveals that sensitivity and selectivity of the NCO are significantly related with the final microstructure combined with constituent species with multiple oxidation states in the spinel structure.