The structure of Au films formed on (001) NaCl surfaces by a dual deposition technique composed of ordinary vacuum deposition and RF ion plating has been studied by electron microscopy. Films ion plated immediately after vacuum deposition were observed to be polycrystalline in structure, while films that were vacuum deposited soon after RF ion plating were observed to be composed of mixture of (001) orientated crystal and polycrystal. Use of this dual technique indicates that the epitaxy of Au film on the (001) NaCl surface depends on the structure of the first layer of crystal on the substrate surface.
Titanium nitride has very high hardness and resistivity to corrosion and abrasion, and its color is very similar to that of gold. However, little quantitative work has been done on the colors of titanium nitride films. Present paper aims at the quantitative evalution of the colors of titanium nitride films prepared by the hollow cathode discharge (HCD) process, and color changes due to variations in Hue as a function of nitrogen partial pressure. A comparison is also made between the golden color of such films and gold films prepared by the electroplating. An integrating sphere with specular cap was used as the optical instrument and CIE chromaticity coordinates as befined by JIS Z 8701 and the Munsell renotation system as befined by JIS Z 8721 were employed to indicate film color. The titanium nitride films showed 2Y-3.5Y for hue, 7-7.5 for value and 3.5-7 for chroma by Munsell renotation, while the gold films showed 2Y-7.5Y for hue, 8-8.5 for value and 2-6 for chroma. Comparing the golden color of the two films, the titanium nitride films were a little lower in color value, but since they are much higer in hardness, they show an extensive potential for decorative applications.
Vapor-deposited coatings have become increasingly important as heat- and corrosion-resistant materials. However, the columnar growth morphology in vapor-deposited films frequently causes a pitting-type corrosion, making vapor deposition less attractive in its application to the production of corrosion-resistant coatings. The present study aimed at clarifying the relationship between coating microstructure and corrosion resistance. Molybdenum films of 5-20μm thickness were ion-plated onto iron substrates. A change in the microstructure of the films with the temperature of the substrate could be explained by the Movchan-Demchishin model. The films became dense and porous at around 800°C, and changed to equi-axed structures at temperatures of about 900°C or higher, in which range the number of pores was found to decrease markedly. Corrosion resistance was evaluated both by a modified CASS test and by weight loss measurements of the coated specimens. The results indicated that the corrosion resistance of the coating varied markedly with the number of pores in the film. The high-temperature deposits (800-1000°C) exhibited excellent corrosion resistance due to the formation of an almost pore-free layer. The influence on corrosion resistance of other deposition parameters such as the substrate bias voltage, coating thickness and angle of vapor incidence was also discussed. A preliminary experiment on the alternate evaporation of Mo and Al revealed that a lamellar film structure resulted in reduced columnar growth morphology.
Ion-plated TiN films for watch case exteriors were studied in terms of decorative properties (appearance, coverage and color) and film structure. Using a substrate of 18-8 stainless steel, the application of over sputter cleaning by Ar discharge produced an austenite grain boundary on the substrate surface, to the detriment of decorative properties. Ion-plated TiN film had excellent film thickness distribution and coverage, and application of this technique to watch case exteriors was found to be ideal. Spectrophotometry showed that the shape of the reflectance curve of ion-plated TiN, TiNXCY film was similar to that of gold plating but the values were lower. The dependance of film structure on acceleration voltage was investigated by X-ray diffraction. A change in the orientation of the TiN (111) plane with acceleration voltage was observed by means of rocking curve, and the orientation was found to be affected by acceleration voltage. Stress in the TiN films was measured by X-ray techniques, showing that ion-plated TiN film had very high stress.
This work is an approach to the application of solid-film lubricants to components requiring lubrication such as sliding or rotating surfaces. Cu/Sn bimetallic coatings were produced on steels by combining ion plating and subsequent annealing at various temperatures. The structure, morphology, hardness, friction and antigalling characteristics of the coatings were examined. The surface of coating [Rs=0.5, Rs; Ratio of Sn film thickness: (Thickness of Sn film)/(Total thickness of bilayered Sn/Cu film)] annealed below 300°C consisted of η-Cu6Sn5 phase, while annealing at 400°C, produced the ε-Cu3Sn phase on all coatings at all values of Rs, from 0.2 to 0.5. The friction coefficients of the bimetallic coatings annealed at various temperatures were much lower than Cu or Sn specimens that were as-ion-plated or uncoated. Further, coatings in the dry rubbed condition had excellent antigalling characteristics.
Film characteristics-film composition, orientation, resistance, etc.-depend on the reaction condition of the reactive ion plating of TiC using CH4 and C2H2 gases as reactants with partially ionized Ti vapor. TiC film plated on steel substrate had a high Hv hardness of 3200Hv at C2H2 gas partial pressure of 0.13Pa, bias voltage of 1kV, ionization current of 700mA, and a distance between ion source and substrate of 8cm. The temperature of the substrate influenced the hardness and phase of the TiC in the film produced by ion plating using CH4 gas as a reactant. The phase of the TiC of the plated film using CH4 gas on the substrate increased at higher temperatures and temperatures higher than 500°C were more effective in obtaining hard TiC films.
In ordinary activated reactive evaporations (ARE), the normal discharge is used for the activation of the reacting species. The results of ion-plating under the abnormal discharge of probe current has been investigated. A pressure of less than 0.01Pa was necessary for an electron-beam gun to evaporate titanium metal, but a relatively high pressure(-1Pa)was required to obtain glow discharge around the substrate: The pressure required for glow discharge, however could be lowered to-0.1 Pa by enhanced ions generated during the abnormal discharge. Concequently, ion-plating can be performed under relatively low pressures. The characteristics of coatings of TiN on SKH-4 were evaluated by the continuous cutting test, which showed a longer life for coated than for uncoated materials
InN, one of the less-studied III-V compound semiconductors, has pontential applications in visible-light opto-electronic devices and high-efficiency solar cells because of its direct energy gap of 1.9eV. InN polycrys talline films were synthesized by rf reactive ion plating; indium was evaporated in a nitrogen rf glow discharge. The plasma process using rf glow discharge resulted in the low-temperature synthesis of InN. Gas pressure and rf power greatly affected the preparation of the InN films, which were successfully prepared at a pressure of 13Pa and rf power of 100W. The deposition rate was 10-20nm/min. The film structure was evaluated by X-ray diffraction, RHEED and TED, and the oriented growth of the InN films was observed. InN single crystals were also observed on NaCl (100) surfaces. The chemical composition was determined by AES. The electrical, optical, chemical and electrochemical properties of the InN films prepared were also investigated. InN films showed n-type conduction and a dark red color. The InN film was found to show the electrochromic effect. The metal-nitride semiconductor has joined the group of electrochromic materials. The InN film electrode showed the particular photoelectrochemical behavior. Therefore, InN is a material of great interest.