Thin films of TiN, ZrN and HfN were deposited by the Arc Ion Plating process onto 18Cr-8Ni steel substrates at various values of PN2 and substrates bias voltage (Bv). Films were characterizated in terms of microhardness, critical load value (Lc) as measured by scratch tester, surface roughness (Ra), residual stress as measured by the sin2φ method, and X-ray diffraction. Hv 2620 for TiN, 3010 for ZrN, 3840 for HfN was obtained at PN2 of 10-1 to a few Pa and Bv of -50∼-100V. Residual stresses were predominant at a PN2 of greater than 6.7×10-2 Pa for TiN, and 6.7×10-2 to 1.3Pa for ZrN, but Bv had no effect on the (111) orientation. HfN films did not show the (111) orientation.
Zirconium boride (ZrB2) thin film has been synthesized on an aluminum substrate by reactive ion plating methods. The following four processes were applied to the synthesis of ZrB2 thin film. (1) Metallic zirconium and BCl3 gas were vaporized on an aluminum substrate by reactive ion plating. (2) A mixture of metallic zirconium and elemental boron was simultaneously deposited on an aluminum plate by ion plating. (3) ZrB2 thin film was prepared with a heating treatment of the multi-layer product after an alternating vaporization using metallic zirconium and elemental boron. (4) Metallic zirconium and B2H6 gas were vaporized on an aluminum plate by reactive ion plating. In these processes, it was found to be difficult to synthesize ZrB2 thin film in terms of the processes from (1) to (3). The process (4) using metallic zirconium and B2H6 gas as a source of boron was found to be more effective for the preparation of ZrB2 thin film when the synthesis was carried out under optimum conditions of a substrate temperature of 410K and a bell-jar pressure of 0.3Pa.
The properties of Cr-N films deposited by reactive ion plating were found to depend on the preparation conditions. Cr+Cr2N films exhibited a fine granular structure and showed better corrosion resistance, and higher Vickers microhardness than ion-plated Cr film. Wear resistance, however, was not as good. Cr2N film was very hard and had good corrosion resistance, but its wear resistance was not satisfactory. CrN films that were deposited at 0.5∼1kV bias voltage and high ionization current showed a strong (200) crystal orientation and exhibited a fine columnar structure. These films were very hard, and had both good wear resistance and corrosion resistance, but too high a bias voltage will have an adverse influence on film properties. This shows that the properties of the film can be changed by controling its composition, crystal orientation and morphology.
TiN films were variously deposited onto SUS 304 stainless steel by an ion plating process using hollow cothode discharge (HCD). The pitting and crevice corrosion resistance of the TiN-coated specimens was estimated in chloride solutions, mainly by the electro-chemical method. The results obtained are as follows; The effects on corrosion resisitance of a TiC coating under the TiN film and of the temperatuer of deposition were not clear, but the effect of a Ti undercoating was evident. Corrosion morphology was also affected by Ti undercoating. In specimens without Ti undercoating, the pitting and crevice corrosion resistance was decreased by TiN coating, whereas with Ti undercoating the pitting potential and starting potential to crevice corrosion became more noble. Accordingly the pitting and crevice corrosion resistance was improved by TiN coating, but the repassivation potential became less nobel and repassivation was restrained as corrosion started.
(Ti, Al)N films having various composition ratios of Ti and Al were deposited onto a hard alloy substrate by reactive RF sputtering using a single power source, the power from which was split by a variable coupling capacitor. A series of (Ti, Al)N specimens was obtained by changing voltage in a mixed argon-nitrogen atmosphere. Film composition were measured by X-ray diffraction and EPMA. The results showed that all the (Ti, Al)N films showed homogenous distribution of Ti and Al. X-ray patterns showed obvious formation of TiN for concentrated Ti side and AlN formation for Al riched side. Those (Ti, Al)N films having Ti-to-Al ratios approximating 1 1 were amorphous. Hardness of the films was from Hv1200 to Hv1300.
RuO2-SiO2 films about 0.3-0.4μm thick were prepared from a RuO2-SiO2 composite target by RF sputtering in an argon atmosphere, and their crystal structure and electrical properties were investigated. The crystallinity of the sputtered RuO2-SiO2 films was found to depend on the volume fraction, x, of SiO2 and on the sputtering power density. Film crystallinity decreased with an increase in x and with a decrease in sputtering power density. The electrical resistivity of the sputtered RuO2-SiO2 films varied with x over a wide range and was divided into three regions: low (x<0.4), transitional (0.4<x<0.6) and high (x>0.6). The temperature dependence of resistivity was also measured for specimens in the low resistivity region. It was found that the TCR of films prepared at low power densities was negative, while for films prepared at high power densities TCR was positive. These results can be explained by a model in which the sputtered RuO2-SiO2 films consist of micro-crystalline RuO2 grains, amorphous RuO2 and amorphous SiO2. The amorphous RuO2 is considered to have a negative TCR.
A particle sputter-coating apparatus that uses a rotational barrel chamber of a special structure is described, along with the technique whereby this apparatus is used with another particle electroplating apparatus developed by the authors to coat Al2O3 particles with titanium and then with copper. These double-coated particles are then molded and sintered in the liquid phase, yielding an elaborate composite material in which Al2O3 is dispersed homogeneously. This copper-based Al2O3 particle-reinforced composite material (PRCM) has the following characteristics: 1) Adhesive bonding strength between copper and Al2O3 is high. 2) The number of remaining pores is minimized and Vickers hardness is very high. This particle coating technique makes it possible to create various kinds of composite materials, and has recently attracted considerable attention as a key technology for new functional composite materials.
Amorphous carbon films were deposited by RF plasma CVD using methane source gas. The optical bandgaps of the films as measured by transmission spectroscopy varied from 1.0 to 1.8eV depending on CVD conditions. The complex refractive indices n-ik of the films were also investigated, and were found to vary from 1.6 to 2.0. The films were almost transparent to near infrared light, but showed strong absorption in the visible spectrum range. The optical properties of the films changed when oxygen and hydrogen were added to the source gas. The extinction coefficient k increased with the addition of oxygen and decreased with addition of hydrogen, but there was little change in refractive index n.
Chemical vapor deposition of ZrB2 and TiB2-ZrB2 composites on mild steel substrates was carried out with the hydorgen reduction of ZrCl4-BCl3 and TiCl4-ZrCl4-BCl3 mixtures. The ZrB2 deposition was carried out at substrate temperatures of 1273K and above, [ZrCl4/ZrCl4+BCl3] gas ratios of 0.33 and above, and Cl/H ratios of 0.13 and below. The deposition of FeB was observed without these conditions. TiB2-ZrB2 composite film was formed at 1273K, and its phase was determined by X-ray diffraction to be ZrB2 within the range of film compositions equivalent to 0-77mol% TiB2. TiB2 phase was identified in compositions of 89mol% TiB2 and above. The lattice constant of the composite film gradually decraesed with an increase in the titanium content of the film, and its sudden drop was observed at the boundary composition of TiB2 and ZrB2 phases. A maximum micro-vickers hardness of about 4600kg·f/mm2 was measured for composite films having the composition of TiB2/ZrB2=1 in molar ratio.
An tentative evaluation was made by cathodoluminescence for diamond films deposited by microwave plasma CVD. The diamond was prepared from source gases of either H2+CH4 or H2+CO. Results obtained by CL analysis were compared with those by XRD, Raman spectroscopy and SE microscopy, and CL turned out to be a very effective technique for evaluating crystallinity of diamonds-both CVD-deposited and natural.
Non-mass analyzed nitrogen ions were implanted at dose of from 1×1017ions cm-2 to 1×1018ions cm-2 into sheets of group-VIa transition metals (Ti, Zr, Hf) and at room temperature using a Zymet implanter model Z-100 at an accelerating voltage of 90keV. Nitride formation in Ti, Zr and Hf was verifed by X-ray thin-film diffraction (TFD), and the distribution of nitrogen and oxygen was determined by glow discharge spectrometry (GDS) or Auger electron spectroscopy (AES). Reflectance and color were also determined. Ti2N, TiN, ZrN, HfN and Hf4N3 phases were observed depending on the implantation dose. Depth profiles suggest that the surface thin layer consisits of a multilayer (oxide/nitride/metal) structure containing oxides. The color of nitrogen-implanted Zr and Hf varied from yellow to reddish yellow with the level of nitrogen content. The reflectance minimum shifted to lower photon energy with increased nitrogen content. This behavior is attributed to the combined effect of the surface structure and the concentration of implanted nitrogen.
In order to investigate the influence of alloying elements, low-carbon alloy steels containing Mo, Nb, V and Cr were ion-nitrided at 823K for 2 and 4h in a 50%N2-50%H2 gas mixture at 800Pa. Samples of the ion-nirtided low-carbon alloy steels were subjected to hardness test, microscopic examination and X-ray diffraction analysis. The following conclusions were reached. Ion-nitriding produced a markedly hardened surface layer on samples containig, Nb, V ans Cr. There was little increase in hardness in samples containing Mo and samples of plain low-carbon steel. Sectional hardness distributions of the nitrided steels showed characteristic shapes attributable to the alloyig elements in the steels. Vanadium and niobium steels showed, respectively, 2 and 3 plateaus in thier hardness distribution curves. A white layer of ε-Fe2-3N nitride was formed on the surface of nitrided samples, and characteristic nitriding layer was formed beneath that nitride layer. The large increase in the hardness of the nitriding layer is attributed to precipitation of the very fine alloy nitrides accompanying the very high levels of precipitation strain.