The fluorination of expanded graphite sheets using polytetrafluoroethylene (PTFE) Ar plasma sputtering was investigated. The graphite sheet was exposed to Ar plasma between two PTFE sheets. The content of fluorine and oxygen at the graphite surface was correlated as a function of plasma treatment power and temperature with the nature of water wettability and surface potential (SP). The fluorine content increased with increasing power and temperature, resulting in increased hydrophobic nature. Water wettability and the electrical nature of the front of the sheet in contact with Ar plasma differed greatly from those on the back of the sheet: the front was more hydrophobic when power was changed, but more hydrophilic when temperature was changed. The SP value for the front became negative, nearly independent of power and temperature. The back still exhibited a positive SP value, the same as an untreated sheet.
Effects of a diamond-like carbon (DLC) interlayer on the interfacial microstructure and adherence between diamond film and a silicon nitride substrate were investigated. The substrate was pretreated in a strong acid solution, followed by ultrasonic microflawing pretreatment. DLC was found to be deposited into etched micropores and to form a uniform film for 2h by rf plasma CVD using CH4-H2 reactant gas. Diamond film was then coated subsequently by microwave plasma CVD using CO-H2 reactant gas. Fine-grained diamond was nucleated onto microflawed DLC film by first-stage CVD for 1h, and diamond film 35μm thick was prepared by second-stage CVD for 29h. Milling tests of the coated specimen using Al-20wt% Si alloy as the work material exhibited higher adherence and longer tool life than the diamond-coated specimen without the DLC interlayer.
The optical and electrical properties of RF-sputtered Al-N films have been controlled by changing the content of nitrogen gas and total sputtering pressure. For Al-rich Al-N films, post-N+-implantation and post-heat-treatment in a nitrogen atmosphere effectively change optical and electrical properties. A new, colorful, wear-resistant, anticorrosion AlN/Al/AlN film has been made by adding a very thin layer of Al between two stoichiometric AlN layers, based on the phenomenon that the coloration of Al-N films is mainly caused by the extra Al in the film and the interference of light. A compositionally and structurally gradient Al-AlN film was fabricated. The structure, morphology, and Al element distribution across the cross section of the gradient film was investigated using X-ray diffraction, SEM, and EMPA
By using rapid-quenched amorphous alloy ribbons and electro- and electroless-deposited films, we plan to develop novel composite magnetic materials. For this purpose, we form magnetic CoP alloy films electroless-deposited on rapid-quenched Fe-based amorphous ribbons. Optimum conditions for film formation are determined using electrochemical polarization. The present study focuses on catalysis effects, the influence of amorphous ribbon surfaces (wheel and free sides), and the composition of amorphous ribbons on properties. The crystallinity of resultant films is evaluated by XRD and SEM.
The effects of phosphorus codeposition on internal stress and occluded hydrogen in electroless plated palladium-phosphorus alloy films were investigated. Phosphorus contents in alloy films were proportional to the 0.2 power of sodium hypophosphite concentration. Tensile stress and occluded hydrogen decreased with an increase in the phosphorus content in alloy films. The decrease of tensile stress in alloy films with phosphorus codeposition was found to inhibit the matching of the palladium crystal with phosphorus.
CuInSe2 was electrodeposited on a Ti substrate from an acidic solution with Cu, In, and Se ions. Cu-Se codeposition started below 0.1V and CuInSe2 was detected below -0.5V. H2 gas evolved under -0.8V. The morphology of CuInSe2 showed a dendritic structure due to the effect of Se0 to Se2- reduction. Deposits formed at -0.5V were p-type semiconductor because cathode currents for deposits in sulphic solutions increased by light irradiation, and the photocurrent for deposits after heat treatment increased greatly.
For the development of electroluminescence devices made from anodic oxide films on aluminum, Eu ions were implanted into a barrier film, and red electroluminescence from Eu3+ was observed during film reanodization. Red electroluminescence from specimens without surface pretreatment occurred at about 100V and its intensity raised with increasing of voltage. It also continued for several minutes with a weak current density of 0.03mA·cm-2 at a constant voltage of 350V. Luminescence intensity was influenced by surface conditions, so electroluminescence from specimens without surface pretreatment was 7 times stronger than with electropolishing. Electroluminescence intensity was thus considered to be influenced by flaws in the film.
The characteristics of photoelectron emission (PE) from copper abraded in organic liquids such as alcohols, aromatics, ether, ketone, and ester have been investigated. PE was measured by varying the wavelength of incident light at several temperatures between 25 and 300°C, which were successively changed in two round cycles of elevating and lowering temperatures. PE intensity depended greatly on the measurement temperature. The maximum PE appearing at 250°C in the temperature-elevation of the first cycle, also, depended markedly on the organic liquids used. The order of the maximum PE value for organic liquids was explained as corresponding significantly with that of the acid base interaction of the organic liquid and abraded surface.