The grinding characteristics of Z-irons seem to be closely related to the deposit density in mechanical plating. In this study, ground products were sized, magnetically separated and chemically analyzed. It was found that: (1) The initial rate of dust formation of ZZ-48H was larger than that of ZZ-48. On further pulverization, dust formation decreased slightly for ZZ-48 but continued at the same rate for ZZ-48H. (2) Although the quantiy of dust collected during pulverization differed for ZZ-48H and ZZ-48, the size distribution of the coarse fractions separated from the dusts was similar. (3) The chemical composition of the dust formed during pulverization and that of the non-magnetics of the -60mesh fraction were almost the same for both ZZ-48 and ZZ-48H. (4) The zinc content of the dust formed during pulverization was greater for ZZ-48H than for ZZ-48, indicates more homogeneous alloying of ZZ-48H by thermal treatment. (5) There is a linear relation between deposit density and Zn content for ZZ-48 and its derivatives.
To clarify the effects of heat treatment on the coating structure, TiN films with (200) and (111) orientation were RF-ion-plated on eutectic steel substrates To average grain size of (200) films was greater than that of (111) films under all the conditions tested. The grain of the (200) films grew at temperatures of 500-700°C, but not during heat treatment at 800°C, in which the substrate passed through a phase transformation during heating and cooling. The ratio between the integrated intensity of X-ray diffraction peaks for the (111) and (200) surfaces was affected in a complicated manner by the heat treatment, but film orientation was not changed
The effects of heat treatment on electroless amorphous NiReP alloy films of various compositions were systematically investigated in respect to their electrical properties (specific resistance and TCR), film structure (X-ray diffraction, TEM and TREED) and crystallization process (DSC). On the basis of heat treatment behavior, the four representative films may be divided into two groups, a lower Re content group (Ni75.9Re1.4P22.7, Ni72.1Re8.3P19.6 and Ni64.8Re21.7P13.7), and a higher Re content group (Ni51.2Re44.0P4.8). In the lower content group, heat teatment produces abrupt reduction in electrical resistance properties at a certain temperature due to precipitation of a Ni3P phase. In the higher content group, resistance properties show an abrupt drop in specific resistance with heat treatment to 200°C, and thereafter are insensitive to heat treatment temperature. The films of higher content group precipitate only metal phases (fcc Ni and hcp Re) under heat treatment, and the insensitivity of the resistance properties is attributed to the fact that the crystallized metal phases contain many grain boundaries (or defects) even under HRTEM (High Resolution Transmission Electron Microscope) at very high magnification.
The utilization factor of the reducing agent was found to change from 20 to 90 per cent with variations in bath composition and plating conditions, and an abrupt decrease was found with an increase in the rate of oxidation of hypophosphite ion (formation of phosphite ion). The wide variations in utilization factor observed in this study can be explained by the mechanism proposed by Van den Meerakker.
Fe-Cr-Ni-P alloys were electrodeposited from a sulfate-glycine bath, and a determination of the influence of bath composition on their composition, and of the condition for amorphous formation was made. The polarization behavior of the alloy deposits was investigated in an acidic solution. It was found that amorphous Fe-Cr-Ni-P alloy deposits were obtained over a wide range of bath compositions. Based on anodic polarization curves in 1N hydrochloric acid at 30°C, it was shown that the presence of chromium and phosphorus in the amorphous alloy deposits have a favorable effect on their corrosion resistance, and that the presence of nickel was effective in increasing the stability of passive films formed in acidic solutions. The same outstanding corrosion resistance was shown under comparision with the anodic polarization curve of Hastelloy C-276.
The corrosive wear of ion plated TiN thin film formed on mild steel by hollow cathode deposition was investigated in NaCl solution. The results show that the conditions of surface damage are classified into three groups depending upon the magnitude of loads: 1) low load…control of corrosion, 2) medium load…control of corrosion and wear, 3) high load…control of wear. Under the control of corrosion with low load, galvanic corrosion of mild steel occurred at the defects of TiN film causing cave-in and finally breakdown of the thin film. Under the control of wear with high load, low mechanical strength and low hardness of mild steel resulted in plastic deformation of substrate and stepwise breakdown of the film. Adhesive wear was also observed partly. Compared with dry environment, wet environment of aqueous solution gave favourable condition for removal of wear powder, cooling and lubrication on wearing surfaces.
The electrodeposition of Cu from Cu(I) ions in ambient-temperature molten salt baths (CuCl-1-butylpyridinium chloride (BPC) system or AlCl3-CuCl-BPC system) has been investigated, and the following results were obtained. (1) The CuCl-BPC binary salt melted at around room temperature, and copper was deposited from it under a 1-electron reaction. Current efficiencies from baths of 66.7mol%CuCl-33.3mol%BPC and 50.0mol%CuCl-50.0mol%BPC were about 100% at 10mA·cm-2 and 90°C. It was also demonstrated that the ion species concerned in the copper deposition are Cu3Cl4- and CuCl2- for the former bath and CuCl2- for the latter. (2) The addition of acetonitrile to CuCl-BPC baths made possible copper deposition under a 1-electron reaction at around room temperature. (3) Copper deposition was also possible from AlCl3-CuCl-BPC ternary baths under a 1-electron reaction, and at 5mA·cm-2 and 70°C, current efficiency was 99.5% and purity was 99.997%.
The inhibiting effect of various organic reagents on the dissolution of aluminum (Al) by 1, 1, 1-trichloroethane (CCl3CH3) was expressed quantitatively in terms of reagent concentrations measured by two different methods 1) critical concentration, in which the induction period was extended to over 1000min in boiling solution, and 2) effective concentration, which inhibits dissolution in the scratch test at room temperature. The correlation between these two types of concentration measurement was analyzed. The dissolution inhibitors were classified into two groups-one comprising esters and ethers, and the other comprising amines, alcohols, ketones, nitriles, nitrocompounds and amides-and regression equations correlating the two types of concentration were obtained for each group. Estimates of induction period critical concentration derived from measured scratch test effective concentration using the regression equations agreed precisely with the experimental results.
Amorphous Ni-Cr-P alloy films were prepared by electrodeposition and their corrosion resistance was evaluated by measuring anodic curves in 1N HCl at 30°C. Phosphorus was added to the alloys for amorphization, and chromium was added to improve passivity. It was found that Ni-Cr-P films can be formed in plating baths of low pH. The results indicate that amorphous Ni-Cr-P alloy films show excellent corrosion resistance in that environment.