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Abstract: The current artificial joint materials need to be further improved for adhesion and service life. In the present research, the adhesion of albumen protein to CrN and CrAlN coatings on Ti alloy and Si wafer is studied via rotational shear flow. CrN and CrAlN coatings provide improved wear resistance over pure Cr. These coatings offer a potential alternative to reduce wear in artificial joints. Previous research has demonstrated that there are two factors that affect protein adhesion: surface roughness and surface chemistry. Here we study effects of material and surface properties of those coatings on protein adhesion. Experimentally, we developed a method to quantitatively evaluate the adhesive strength of proteins to the surface. Subsequently we study the interfacial mechanisms between coating surfaces and protein molecules. Results indicate that the protein adhesion depends on the substrate chemistry. The CrN and CrAlN coatings improve wear resistance with minimum to no influence with the substrate''s interaction with the proteins. [Copyright &y& Elsevier]

The pure oxygen was introduced into the growth environment of the single crystal diamond with different contents, and the growth characteristics of single crystal diamond and the reaction dynamics in the plasma were studied in detail. As the ratio of O 2 to H 2 is up to 1.5%, the unique shaped etching pits with eight symmetric crystallographic planes appear. Optical emission spectra present typical characteristic radicals in the O 2 incorporated growth environment. With amount of O 2 increases, the growth rate decreases gradually due to the low active carbon source concentration and electron temperature. In the carbon contained hydrogen plasma, O 2 will react with CH radicals preferentially at low concentration and the dynamic equilibrium of CH and C 2 radicals was achieved at the O 2 concentration of 0.5% and 1%. Accompanying with the O 2 addition, the nitrogen and silicon related impurities have been reduced during the epitaxial growth process. Meanwhile, all of the FWHM of characteristic peaks in Raman decrease obviously after the epitaxial growth without and with O 2 addition, and FWHM of most samples are about 2.6 cm −1 , which are comparable with the natural type IIa SCD without stress. [ABSTRACT FROM AUTHOR]

Surface etching of single-crystal diamond (SCD) in hydrogen plasma plays a decisive role for high-quality homoepitaxy and surface conduction of diamond. The complexity of surface/subsurface condition such as defects would give rise to the distinct morphology features and even further result in the unpredictable properties. Correspondingly, the evolutionary relationship between the morphology and electrical properties of mechanically polished SCDs which have typical cleavage damage in microns depth after hydrogen plasma treatment still needs to be further completed. In this work, the chemical vapor deposited (CVD) SCDs with uniform polishing-caused subsurface cleavage were immersed in microwave hydrogen plasma for variable duration. Time-dependent morphological evolution, multi-mode etched pits (EPs) (resulting from local defects/cracks and dislocations) and associated etching mechanism were comprehensively studied. At the early stage of plasma treatment before 60 min, owing to the obvious surface roughing generated by preferential etching (with the rate of >400 nm/h) of severe mechanically damaged regions, the hole mobility was significantly deteriorated, also accompanying with the apparent drop of sheet concentration. Concurrently, the deposited surface sp 2 amorphous carbon (a -C) nanodots on diamond surface and non- sp 3 hydrogen bonds reconstruction, which arising from defect-etching produced local abundant carbon-containing radicals or possible exfoliation generated by hydrogen penetration of massive defective regions, also would play an adverse role for the conduction associated with (100) C–H surface. However, the surface roughness was reduced from the maximum 13.2 nm–4.2 nm by prolonging etching, resulting from the smoothing effect of small-angle crystal misorientation on waved height difference related to the uniform (111) cleavage and the removal of dense irregular EPs associated with polishing-induced local defects as well as the vanishing of surface a -C nanodots. In this case, the improvement of surface electrical properties together with the negative correlation of the mobility and sheet concentration were appeared by the gradual formation of (100) diamond surface and the building of uniform (100) C–H bonds. • CVD SCDs with typical subsurface damages(defects) were treated in pure hydrogen plasma. • Morphology evolution associated with polishing defects was time-dependently presented. • Surface sp2 nanodots deposition from defect-etching and CH reconstruction would affect electrical properties. [ABSTRACT FROM AUTHOR]

To improve the transmittance of chemical vapor deposition (CVD) diamond, erbium(III) oxide (Er 2 O 3) antireflective films were deposited on CVD diamond substrates by radio frequency (RF) magnetron sputtering. Effects of deposition temperature on structure, chemical composition and properties of the samples were investigated. A strong correlation was observed between the deposition temperature and crystalline structure evolution of the Er 2 O 3 antireflective films. With rising deposition temperature, the deposition rate, grain size and surface roughness of the Er 2 O 3 antireflective films increased. Changes of composition and chemical bonding of the films were analyzed. Results showed that the amount of bonding between Er and O atoms surface as the temperature increased. The films were structured by amorphous, monoclinic and cubic phase, with preferential orientations of C-Er 2 O 3 {222} at deposition temperature increased to 400 °C. A thickness of 10 nm transition layer was observed between the Er 2 O 3 antireflective films and the CVD diamond substrates by transmission electron microscopy (TEM). Moreover, the transition layer feature primarily consisted of Er, O and C. The hardness and modulus of Er 2 O 3 antireflective films were increased for higher deposition temperature, which positively affects the IR transmittance and adhesion strength of the Er 2 O 3 antireflective films on CVD diamond substrates. • The maximum transmittance of Er 2 O 3 /diamond sample was 80% in 7–11 μm range. • Texturization of Er 2 O 3 film interface was studied by HRTEM. • The higher deposition temperature favors crystallization of Er 2 O 3 film. • This study meets the requirements of windows for infrared (IR) imaging systems coating in the LWIR range. [ABSTRACT FROM AUTHOR]

It was predicted that diamond would play an irreplaceable role in thermal management technology at ultra-high heat flux levels owing to its outstanding thermal conductivity. In this work, an ultra-thick diamond plate, which was realized by direct-current (DC) arc jet plasma chemical vapor deposition (CVD) system, was fabricated into an all-diamond microchannel heat sink by laser. The convective heat transfer capacity, thermal resistance, device surface temperature and pressure drop of the all-diamond MCHS were systematically studied under the heat flux of 40–120 W/cm2 based on a single-phase heat transfer system, comparing to the commercially available aluminum MCHS. Under the assumption that the extreme service temperature of the device at 100 °C, the advantage of all-diamond MCHS in reducing fluid flow is evaluated. The results demonstrated that the heat transfer coefficient of the all-diamond MCHS was in the range of 5637.10–11447.20 W/m2‧K, which is 37%–73% higher than that of the aluminum MCHS with the same geometry. The volume flow of the fluid in the diamond MCHS is merely 40% of that in the aluminum MCHS could effectively reduce the equipment load owing to the significant advantage of the all-diamond MCHS in reducing the device surface temperature and thermal resistance. • An all-diamond MCHS was obtained on an ultra-thick CVD diamond plate. • Diamond MCHS has the higher fin efficiency due to its superior thermal conductivity. • The heat transfer coefficient of an all-diamond MCHS was 37%–73% higher than that of an aluminum MCHS. • Only 40% of volume flow rate of coolant for an aluminum MCHS operation can satisfy the requirement of an all-diamond MCHS. [ABSTRACT FROM AUTHOR]

Nd 2 O 3 film is a functional film with great potential application value. In this paper, thinNd 2 O 3 film was prepared on the surface of Si substrates using RF magnetron reactive sputtering. Nd 2 O 3 film with different crystal structures were controlled by changing the deposition temperature. The results show that the Nd 2 O 3 film with a cubic structure can be obtained at 150 °C, while a hexagonal structure appears at 250 °C and above. The refractive indices of the cubic and hexagonal Nd 2 O 3 films were 1.736 and 2.130, respectively. Moreover, the principle of the influence of deposition temperature on the refractive index of the film was illustrated. The hardness and the elastic modulus of the cubic Nd 2 O 3 film were 6.3 GPa and 102 GPa, respectively, which are much lower than the 9.9 GPa and 145 GPa of the hexagonal Nd 2 O 3 film. In addition, with a double-sided cubic Nd 2 O 3 film, the maximum transmittance of the diamond film reached 87.54%. The results show that the Nd 2 O 3 film is an anti-reflection film suitable for optical applications. • Nd 2 O 3 films with cubic and hexagonal structures were prepared, respectively. • The mechanical and optical properties of two kinds of Nd 2 O 3 films were compared. • Hexagonal Nd 2 O 3 film shows hardness of 9.9 GPa and elastic modulus of 145 GPa. • Diamond presents the maximum transmittance of 87.54% at 11.2 μm with Nd 2 O 3 films. [ABSTRACT FROM AUTHOR]