We studied the influence of bath composition, operating conditions, and impurities on a platinum electroforming bath using hexahydroxoplatinate salt. The effect of bath temperature on deposite were studied using a platinum concentration of 13g/L and a pH of 135. Crack-free deposits resulted at temperatures of exceeding 85°C. At a platinum concentration of 26g/L, the pH was 13.5 and temperature 90°C, yielding a 60μm platinum foil. The platinum content of deposits exceeded 99.9%, which contained palladium, rhodium, gold, silver, copper, and iron impurities. X-ray diffraction imaging showed a strong (200) orientation on ductile deposits. Deposit hardness exceeded 300Hv and hardness decreased in heat treatment exceeding 600°C. The bath thus is easily influenced by impurities. Calcium is thought to be a deterioration agent. The presence of calcium, strontium or barium made the deposit less ductile and brighter. The influence of alkaline earth metals was eliminated through electrolysis, coprecipitation with magnesium hydroxide, and absorption to chelate resin.
TiC-TiN binary system films were prepared by rf magnetron sputtering using a TiC-TiN compound target. Film chemical composition and structural changes were examined by chemical state analysis, using electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and x-ray diffraction (XRD). Tribological properties of the films were studied using a pin-on-plate type reciprocating friction tester. The value of x exhibited by the TiCxN1-x system ranged from 022 to 0.74 as a function of deposition position. The crystal structure of TiCxN1-x films formed TiC-TiN system solid solutions. The microvickers hardness of the films increased with x, reaching a maximum at around 0.69. The microvickers hardness also increased as the (200) preferred orientation increased. The rate of wear TiCxN1-x (x=0.22∼0.74) films decreased with x, exhibiting a minimum value at about 0.4∼07. The friction coefficient decreased steadily with x, reaching a minimum at 0.4.
Electrodeposition of CdTe from a variety of CdSO4-TeO2-NH3-(NH4)2SO4 aqueous solutions was studied to determine optimum conditions for crystalline CdTe deposition. The deposit obtained from an electrolyte whose Cd (II)/Te (IV) concentration ratio was 1, showed an amorphous structure and tellurium-rich composition. Polycrystalline CdTe was obtained by partial oxidation of Te (IV) to Te (VI) in the solution, suppressing Te deposition, and by a decreasing the total ammonia concentration, accelerating Cd deposition. In electrodeposition at a cathode potential of -0.80V vs SHE and a total ammonia concentration of 5kmolm-3, polycrystalline CdTe was obtained at a Cd (II)/Te (IV) concentration ratio of 25 to 4. Particularly at a Cd (II)/Te (IV) concentration ratio of 3, the deposit showed high crystallinity, although Cd codposition was observed. Increasing the cathodic potential from -0.80V to -0.70V vs SHE and keeping the Cd (II)/Te (IV) concentration ratio at 3, suppressed Cd codposition. These results suggest that a polycrystalline CdTe single phase is obtained by controlling the cathodic potential and the Cd (II)/Te (IV) concentration ratio of the ammonia-alkaline solution, in which TeO2 solubility is higher than that in acidic solution.
In order to improve corrosion resistance and thermal efficiency of aluminium car air conditioning units, a coating which provides hydrophilicity is formed over the chromate coating. However, the odors associated with this hydrophilic coating have become an issue. This paper reviews odors associated with surface treatment coatings, and discusses a resin coating process which provides corrosion resistance and hydrophilicity to air conditioning units, without any odor.
Alumina-composite botanical abrasives were prepared by using aliphatic acid, wax, etc. to make a walunt shell composite with alumina powder. A barrel polishing apparatus was used to perform polishing experiments on various composite ceramics of the Al2O3-Y2O3-ZrO2-MgO family (Family I, with high hardness and tenacity) and the Al2O3-Y2O3-MgO family (Family II, with high porosity). The alumina-composite botanical abrasives were found (1) to be capable of gradually increasing the polished amount with polishing time for all ceramics, with resulting improvement of surface roughness, (2) to be effective for smoothing surfaces of Family I composite ceramics, though with low processing efficiency, and (3) to exhibit high polishing speeds for Family II composite ceramics, though with high roughness of the finished surface.