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The impact of the addition of TiO2 nanoparticles and nanowires on the morphology, phase characteristics, contact angle, and electrochemical performance of chemically bonded phosphate ceramic coatings (CBPCs) was investigated. The chemical composition and surface morphology of the TiO2 nanoparticle and nanowire modified with and without (heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane were characterized. Results indicated that the hydrophobic –CF2– and –CF3 groups were successfully introduced into the TiO2 nanoparticles and nanowires after modification. Corrosion resistance of CBPCs with TiO2 was evidently improved compared with that without TiO2. Such improvement was mainly due to the combined effects of low surface energy materials and micro/nano structures. In addition, CBPCs with TiO2 nanowires exhibited higher hydrophobicity and corrosion resistance than those with TiO2 nanoparticles because of the special columnar structure of the nanowires.

Existing medical materials (such as silicone rubber, glass slides, etc.) fail to meet the functional requirements of biosensing, cell culture, and drug delivery due to their poor wettability. The preparation of polyelectrolyte coatings with excellent wettability and protein adsorption helps broaden the application of medical materials. Poly(acrylic acid) (PAA) is a common polyelectrolyte with stronger protein adsorption, but the existing methods for obtaining PAA coating have certain shortcomings to limit their industrial applications. In this study, dopamine (DA) was used to polymerize and co-deposit acrylic acid (AA) in weak acid solution to functionalize the surface of materials, and the effects of different mass ratios of DA/AA on the wettability and protein adsorption of the coating were deeply investigated. The results demonstrate that PDA/PAA coating is successfully prepared on the surface of four substrates and greatly reduces the water contact angle of these surfaces. Moreover, these coatings show excellent protein adsorption, and the amount of adsorbed protein on the coated QCM chip is increased by 57.74% than the uncoated QCM chip. In addition, the coating has a certain pH responsiveness, and its wettability and protein adsorption are closely related to the pH of the solution. The preparation strategy proposed is simple and substrate-independent, which provides valuable insights into the application of the one-step polymerization and co-deposition strategy under weak acid conditions.

In order to obtain a high material removal rate (MRR) with good surface quality, the electro-Fenton reaction was used to assist the chemical mechanical polishing (CMP) for the gallium nitride (GaN) substrate. The fluorospectrophotometry, potentiodynamic polarization method and X-ray photoelectron spectroscopy (XPS) were applied to analyze the enhancement mechanism of the CMP of GaN assisted by electro-Fenton reaction. The results revealed that the hydroxyl radical (·OH) concentration in the electro-Fenton solution increased by 41.75%, and the corrosion potential decreased by 24.67% compared with the Fenton solution, which proved that the electro-Fenton solution had strong corrosion characteristics and the gallium oxide (Ga2O3) formation rate on the wafer surface was accelerated. A high MRR of 274.45 nm h−1 with surface roughness (Ra) of 0.88 nm was obtained by electro-Fenton solution. The reduction reaction of the electric field increased the conversion rate of ferrous ions (Fe2+) and ferric ions (Fe3+) effectively and promoted the decomposition of the H2O2 solution. Meanwhile, the oxidation reaction on the GaN wafer surface was enhanced, and high processing efficiency was achieved. Furthermore, the electric field generated a small amount of H2O2, which increased the ·OH concentration and improved the oxidation characteristics of the solution.

Zinc oxide (ZnO) decorated multi-walled carbon nanotubes (MWCNTs) hybrid material was prepared to improve the tribological performance of chemically bonded ceramic coatings. TEM results reveal that ZnO has been successfully fabricated on the surface of MWCNTs. The tribological performance of the ceramic coatings with MWCNTs–ZnO hybrid material was investigated using a ball-on-disc method. The results show that the friction coefficient and wear rate of the ceramic coatings decrease with the increase of MWCNTs–ZnO hybrid material. The ceramic coatings with MWCNTs-ZnO hybrid material shows a smooth worn surface with less cracks and delamination. In addition, the worn surface of the counterpart ball shows a smaller worn area and a smooth surface. The excellent wear resistance of the ceramic coatings is attributed to the good bonding strength between MWCNTs–ZnO hybrid material and ceramic matrix.

Hybridization of nitric oxide (NO) donors with known anti-cancer agents have been emerged as a strategy to achieve improved therapeutic effect and to overcome chemo-resistance in cancer therapy. In this study, furoxan moiety as an efficient NO donor was introduced to phenstatin, a microtubule-interfering agent (MIA), leading to the design and synthesis of a series of furoxan-based NO-releasing arylphenones derivatives. In biological evaluation, the synthesized compounds showed moderate to potent anti-tumor activities against several human cancer cell lines. Among them, compound 15h showed the most potent activities against both chemo-sensitive and resistant cancer cell lines with IC

The investigation of the structural characteristics of chiral drugs in physiological environments is a challenging research topic, which may lead to a better understanding of how the drugs work. Raman optical activity (ROA) spectroscopy in combination with density functional theory (DFT) calculations was exploited to inspect the structural changes in penicillamine under different acid–base states in aqueous solutions. The B3LYP/aug-cc-PVDZ method was employed and the implicit solvation model density (SMD) was considered for describing the solvation effect in H2O. The conformations of penicillamine varied with pH, but penicillamine was liable to stabilize in the form of the PC conformation (the sulfur atom is in a trans orientation with respect to carboxylate) in most cases for both D- and L-isomers. The relationship between the conformations of penicillamine and the ROA peaks, as well as peak assignments, were comprehensively studied and elucidated. In the fingerprint region, two ROA couplets and one ROA triplet with different patterns were recognized. The intensity, sign and frequency of the corresponding peaks also changed with varying pH. Deuteration was carried out to identify the vibrational modes, and the ROA peaks of the deuterated amino group in particular are sensitive to change in the ambient environment. The results are expected not only to serve as a reference for the interpretation of the ROA spectra of penicillamine and other chiral drugs with analogous structures but also to evaluate the structural changes of chiral molecules in physiological environments, which will form the basis of further exploration of the effects of structural characteristics on the pharmacological and toxicological properties of chiral drugs.

In order to obtain a high material removal rate and good surface quality, the effect of Cu2+ ions and glycine complex as a catalyst on the chemical mechanical polishing (CMP) performance of Si-face 6H-SiC substrates was investigated. The results indicated that the slurry with Cu2+-glycine complex had a higher material removal rate (MRR) and better surface quality than that without Cu2+-glycine complex. The maximum MRR of the Si-face 6H-SiC substrate was 83 nm/h with an average roughness (Ra) of 0.336 nm using the slurry containing 6wt% silica (SiO2) and 4wt% hydrogen peroxide (H2O2) at pH 10. In contrast, when Cu2+-glycine complex were added as a catalyst, the maximum MRR was increased to 118 nm/h with Ra of 0.155 nm. The ultraviolet–visible (UV–vis) spectroscopy analysis indicated that the Cu2+-glycine complex was an effective catalyst for the decomposition of H2O2 to generate more hydroxyl (·OH) radicals. Meanwhile, due to the fact that more softened layer was formed and the SiO2 abrasive nanoparticles were deeply pressed into the softened layer to produce a plowing action under the polishing pressure, coefficient of friction (COF) was increased by adding the Cu2+-glycine complex. Finally, the polishing mechanism of the Si-face 6H-SiC substrates using the Cu2+-glycine complex was discussed.

In this study, bio-waste catla fish scale (CFS) was used as a reinforcing agent in polypropylene (PP) for the fabrication of biomaterials by using a twin-screw extrusion technique. Tensile strength...

To enhance the compactness of the chemically bonded phosphate ceramic coatings (CBPCs), different inorganic curing agents (MgO, CaO, and ZnO) are selected as the reinforcement. Tribological experiment and the analysis of microstructure, phase characterization and mechanical performance are carried out to clarify the mechanism of different curing agents on the effect of wear performance. It is found that the curing agents place a significant role on the wear performance of the coating. Compared with coating without curing agents, more bonded phase (AlPO4) can be detected when curing agents (MgO, CaO) are used, which is mainly resulted by the high heat release from MgO and CaO related reactions, and this released heat energy enhances the formation of AlPO4. The results indicate that the morphology and tribological performance of CBPCs using different kinds of curing agents are dependent on the weight ratio of AlPO4 to α-Al2O3 (defined as RPA). The suitable value of RPA will not only improve the bonding strength among the ceramic particles, but also decreases the quantity of defects (such as pores). Upon the above results, CBPCs with MgO process superior wear resistance due to their dense and uniform microstructure.

Graphene oxide (GO) decorated by titanium dioxide (TiO2) was fabricated and introduced into the chemically bonded ceramic coatings as a nanofiller. The analysis of the results of thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and transmission electron microscopy (TEM) show that TiO2 has decorated on the surface of GO by chemical bonds. Furthermore, the effect of incorporating GO-TiO2 on properties of ceramic coatings was investigated. The results show that GO-TiO2 achieved a homogeneous dispersion and compatibility in ceramic matrix without obvious cracks. The potentiodynamic polarization test was conducted to investigate the influence of GO-TiO2 on the corrosion behavior. The results demonstrated that corrosion resistance of ceramic coatings remarkably enhanced by adding GO-TiO2. Furthermore, the anticorrosive mechanisms of ceramic coatings with GO-TiO2 were tentatively discussed.

In this study, the chemically bonded phosphate ceramic coating reinforced with nano-titanium dioxide is prepared on the AISI 304L stainless steel by different curing temperatures. The structure evolution, surface roughness, wettability and corrosion resistance of the coating are investigated. The results indicate that with the increase of the curing temperature, the main curing reactions become different, resulting in different reactants as the bonded phase. When the curing temperature increases, the bonded phase translates from aluminum hydrogen phosphate hydrate (AlH3(PO4)2·3H2O) phase to berlinite (AlPO4) phase, leading to the increase of the corrosion protection property of the coating. That is because berlinite phase can provide a strong bond between ceramic particles and enhance the strength of the coating. Moreover, berlinite phase possesses the low density and more likely distributes on the surface of the coating, which can more effectively protect the stainless steel free from chloride ions destruction. In addition, berlinite phase also increases with the introduction of nano-titanium dioxide. However, compared with nano-titanium dioxide, the curing temperature can better promote the formation of berlinite phase. Therefore, the curing temperature more contributes to the wettability and corrosion protection property of the coating.

The curing agents play an important role on the properties of the chemically bonded phosphate ceramic coatings (CBPCs). To investigate the influence of curing agents on the thermal property and corrosion resistance of CBPCs, the coatings with different curing agents were prepared on the mild steel (Q235). The analysis of thermal property and phase characterization shows that the high peak temperature of curing decreases with the introduction of curing agents, and the weight ratio of AlPO4 to α-Al2O3 (RAA) of the coatings is also influenced by curing agents resulted by the high heat release from MgO, CaO, and ZnO-related reactions. In addition, the results of scanning electron microscopy (SEM) and electrochemical experiments reveal that the bonding strength among the ceramic particles and the defects content of the coatings, which affects the inhibition properties of CBPCs have a relationship with the value of RAA. Typically, the impedance value of CBPC with the best curing agent (MgO) are around 40,000 ohm cm2, which is 4624 times larger than that of the bare mild steel (8.65 ohm cm2).

Nanoscale deformation behavior of aluminum at sliding interface was investigated by nanoscratch experiment and X-ray photoelectron spec-troscopy (XPS) in variable conditions involving dry, water and aqueous H2O2, which has not been discussed previously. It was found that deformation of aluminum in the nanoscratch process could be divided into two regimes relying on the evolution of frictional coefficient. Similar results have been observed in dry and water conditions. However, the stick-slip behavior is integrated into deformation process with aqueous H2O2 compared with the results of that in dry and water conditions, resulting from the formation and breaking of chemical bonds interaction of OH and Al atom. In addition, this deformation behavior is described in the framework of a mathematical model based on Mo’s theory using the atomic contact concept instead of asperity contact, which relates the transition of friction from sub-linear to linear and deformation changing from elastic to changing elastic-plastic. Finally, a parameter of critical energy barrier is employed to reveal the atomic material removal mechanism in Al chemical mechanical planarization (CMP) process with the consideration of chemical actions and nanoscale deformation behavior.

To promote anti-corrosion property of chemically bonded phosphate ceramic coatings (CBPCs), the nano-TiO2 is selected as the reinforcement. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy Dispersive Spectrometer (EDS) and the electrochemical analysis are carried out to clarify the role of nano-TiO2 on the improvement of anti-corrosion performance. The experiments show that with the addition of nano-TiO2, the curing temperature and the activation energy of the curing process increase, which allows longest reaction and positively drives curing reactions at elevated conversions. The enhancement of anti-corrosion performance of CBPCs reinforced by nano-TiO2 particles is based on three main mechanisms. Firstly, more bonded phase (AlPO4) can be formed with the addition of nano-TiO2, which can help CBPCs to get more compact microstructure. Additionally, AlPO4 particles possess the low density and good corrosion resistance, which leads to the increase in the corrosion resistance of CBPCs. Secondly, increasing content of nano-TiO2 can also strengthen the compactness of CBPCs to protect the substrates from the penetration of aggressive electrolyte and prolong electrolyte diffusion path. Thirdly, through the analysis of microstructure of CBPCs, it is found that most of the hydrophobic nano-TiO2 particles homogeneously distribute on the surface of CBPCs. Therefore, CBPCs show well hydrophobic performance, which can further improve the anti-corrosion property of themselves.

Ceria-coated silica (SiO2/CeO2) composite abrasives were prepared through a novel homogeneous precipitation method using commercial silica (SiO2) sol as the silicon resource and cerium nitrate (Ce(NO3)3) and hexamethylenetetramine (HMT) aqueous mixtures as coating precursors. The phase composition, nano-topography, size distribution, and chemical structure of as-prepared particles were characterized by X-ray diffraction, transmission electron microscopy, Zetasizer Nano ZS90 and Fourier infrared spectra. In addition, the possible coating mechanism was discussed. Then, chemical mechanical planarization behaviors of SiO2 sol, ceria (CeO2) sol, and the novel abrasives and on Si-face (0001) 6H-SiC were investigated by atomic force microscopy. The results indicated that the composite particles were mono-dispersed nano-spheres composed of amorphous SiO2 core and cubic fluorite CeO2 shell, possessing complete core–shell structure and particle size of about 110 nm. CeO2 shell (10 nm) grew on the surface of SiO2 core by formation of Ce–O–Si chemical bonds, forming stable core–shell structure. SiO2/CeO2 composite abrasives provided an exponentially high material remove rate (MRR) of 1207 nm h−1 and an impressive surface finish with roughness average (Ra) 0.216 nm due to its active chemical property and unique structure.

To further enhance the corrosion resistance of chemically bonded phosphate ceramic coating, TiO2 was grafted on the surface of GO to enhance the interfacial adhesion between GO and the coating. SEM results show that the presence of TiO2 on GO creates a good interfacial adhesion between GO and the coating. In addition, EIS experiments were carried out to investigate the performance of the coatings on the corrosion resistance. The result indicates that the corrosion resistance is enhanced with the introduction of GO-TiO2 hybrid material. Beside of the influence of GO on the corrosion resistance, the good interfacial adhesion between GO and the coating with the presence of TiO2 hybrid material can consume more fracture energy to stop the crack propagation, which leads to the high corrosion resistance.

To improve tribological performance of chemically bonded phosphate ceramic coatings, the graphene nano-platelets (GNPs) were selected as the reinforcement. Tribological experiment and the analysis of SEM, EDS and Raman were conducted to clarify the mechanism of graphene on the improvement of tribological performance. It was found that, the worn surface of the coating with GNPs is smoother than the one without GNPs, and these GNPs were extruded out and adhered to the worn surface forming the lubricating tribofilm. Besides, the wear volume decreases with the introduction of GNPs. The reason behind this is that these GNPs can lead to the absorption of the fracture energy, which further can improve the mechanical property of the ceramic. This improvement makes the ceramic more tolerant to damage during the wear. Additionally, the decrease of the internal stress of contact surface because of the large contact surface induced by the smooth worn surface results in the lower wear. The friction coefficient shows the similar trends with the wear volume. The lubricant effect of the adhered lubricating tribofilm stemming from the weak interfacial shear strength between graphene platelets dominantly leads to the decrease in friction coefficient. Besides, the smaller internal stress induced by the smooth surface also contributes to the low friction coefficient because of the direct proportionality between the interfacial shear strength and the contact pressure.

The paper investigates preparation and mechanical performances of a composite ceramic coating reinforced by graphene and multi-walled carbon nanotube. The carbon nanotube is functionalized with the carboxyl functional group (–COOH) and un-functionalized with sodium dodecyl benzene sulfonate (SDBS). The structure of the functionalized and hybrid-functionalized carbon nanotube is identified using infrared spectroscopy (FTIR analysis). The coating is brushed on the matrix and then cures under temperature lower than 250°C. The morphological and cross section features are studied by scanning electron microscopy (SEM). The distributions of hardness and fracture toughness are determined using a microhardness tester. The adhesive strength is evaluated using a universal tensile tester. The tribological properties are detected using friction wear testing machine. The experimental results show that the structure of the composite coating is compact, and both graphene and hybridtreated carbon nanotube are well dispersed. Addition of 0.2 wt % graphene and 0.2 wt % hybrid-functionalized carbon nanotube results in a prominent increase in hardness and fracture toughness. Meanwhile, the adhesive strength between the composite coating and the metallic substrate is well improved due to the high tensile strength of both graphene and carbon nanotube. Compared with pure alumina coating, the friction coefficient as well as the wear depth and width of grinding crack of the composite coating is much lower.

With thermal chemical reaction, the chemically bonded ceramic coatings are prepared on A3 steel. Influence of zinc oxide on corrosion resistance of the coating is investigated by corrosion polarization analysis. It is found that the chemically bonded ceramic coatings show the outstanding corrosion resistance. In addition, the coating with zinc oxide possesses a smaller reaction rate and corrosion current density than the coating without zinc oxide. Scanning electron microscope (SEM) analysis and X-ray diffraction (XRD) analysis are conducted to find the reason. Without adding zinc oxide, AlPO4 is the main binding phase connecting with the particles in the coating, and the micro structure of the particles can be seen clearly. However, with adding zinc oxide, a new binding phase Zn3(PO4)2 is found in the coating. Besides, the particles in the coating are fully covered with Zn3(PO4)2 and AlPO4, and the micro structure of the particles cannot be clearly seen. The particles have a better cover with the binding phase compared with the particles without zinc oxide. Therefore, adding zinc oxide makes the coating more compact that hinders access of H2O, O2, and Cl– to the substrate with the compact coatings, which improves the corrosion resistance of the chemically bonded ceramic coatings.

A mathematical model for the influence of the anti-friction material on friction is presented. The predictions of the model are compared with the experimental results and show good agreements. In addition, the predictions of the present model indicate that the friction coefficient initially decreases with the increase in the normal force and follows by a plateau. For sufficiently small normal loads, the friction coefficient with anti-friction material has no difference with that without anti-friction material. And then, the difference between them increases with the increase in the normal force and the friction coefficient with anti-friction material is smaller than that without anti-friction material. With the further increase in the normal force, the difference begins to level off. This study provides some insights into friction material designing.