Delamination and blistering behavior at the interface of the base plate and insulating layer were investigated during the hot press process for applying an insulating film to organic composite coated steel sheets with anti-fingerprint properties, which are used for printed curcuit boards. A chromate conversion film on an electrogalvanized coating was found to generate water by a dehydration reaction during the hot press process, which produced ZnO and H2 gas at the surface of the zinc layer and possibly induced delamination at the interface of the chromate film and zinc coating. Deterioration of secondary film adhesion after a humid cabinet test was attributed to rapid volumetric expansion due to the evaporation of water that had penetrated from the atmosphere through the insulating layer.
Influence of the impurities in electrogalvanized coatings on film adhesion in organic composite coated steel sheets was investigated. A trace of Pb in the electrogalvanized coating layer caused a marked deterioration in film adhesion at high temperature, while the addition of Ni effectively improved it. A chromate conversion film on an electrogalvanized coating layer containing Pb was found to have larger amounts of the OH group than a film on a zinc coating containing Ni. It is suggested that the larger quantity of H2O generated from the electrogalvanized coating containing Pb by a dehydration reaction at elevated temperature progressively attacked the surface of the electrogalvanized coating layer, producing ZnO and H2 gas, which caused deterioration of film adhesion, leading to delamination and blisters during the hot pressprocess.
Baths composed of sulfuric acid (1.5M) were prepared on containing alcohols, ketones and aldehydes as viscosity improvers in amounts ranging from 50∼150mL/L. Anodization was carried out for 30min at a current density of 2A/dm2 at 10°C. It was found that sulfate mobility and the incorporation of sulfate in the coatings decreased with increasing concentration of the viscosity improvers. The coatings formed in baths containing were harder than those formed in baths without viscosity improvers. The C. R. value was higher for coatings formed in baths containing alcohols than for coatings formed in H2SO4, solution, but lower for coatings formed in baths containing ketones or aldehydes.
To obtain cathodes for the electrolysis of sodium chloride, by electroless Ni-S-P alloy plating on soft iron plates, deposits containing various levels of sulfur content were prepared using ammoniacal alkaline citrate baths containing sodium hypophophate as the reducing agent and trace additives including sulfur. The following results were obtained: 1) Adding 10ppm sodium thiosulfate to the plating bath made it possible to prepare deposits containing up to 5% sulfur. 2) In baths not containing sodium citrate, the deposition rate increased, but the sulfur content in the deposits decreased. 3) When the thickness of deposits increased, their sulfur content decreased and deposition stopped.
The structure and polarization properties of deposits containing a high level of sulfur, obtained from electroless Ni-S-P alloy plating baths by the addition of sodium thiosulfate were investigated. The following results were obtained: 1) When the phosphorus content of the deposits was changed, the hydrogen overvoltage scarcely varied. As the phosphorus content in the deposits increased, their corrosion resistance was improved. 2) Examination of X-ray diffraction patterns revealed that particle size increased with increasing sulfur content and decreasing phosphorus content in the deposits. 3) Examination of polarization curves showed that hydrogen overvoltage decreased with increasing sulfur content in the deposits. 4) The corrosion resistance of the deposits improved as the sulfur content in the deposits increased to 0.5%∼0.8%, and thereafter decreased.
The influence of solution pH on composite ceramic deposition from zinc sulfate baths containing a suspension of alumina particles averaging 1μm in diameter for use as an abrasion-resistance material was investigated, and the following results were obtained. (1) Zinc ions adsorbed on the alumina particles, in amounts that incrcased with inceases in solution pH until the surface was saturated by the adsorbate. (2) An amount of alumina particles in an electrodeposited composite coating increased with increases in solution pH, reaching a maximum at the pH at which the precipitation of zinc hydroxide began. (3) Part of the zinc hydroxide adsorbed on the alumina particles and on the cathode was reduced electrolytically to melallic zinc and this electrolytic reduction of the zinc hydroxide also advanced the codeposition of the alumina particles into the composite coating. (4) Some zinc hydroxide was always present in the electrodeposited composite coating as a nonmetallic impurity.
The influences of the surface roughness of the substrate, current density of electrodeposition and distribution density of diamond grits on the adhesion of electrodeposited nickel film are investigated. Adhesion of the deposited films was evaluated by the elongation of specimens in which the film deposited on the substrate separated from it or divided into several parts in tension testing. The surface roughness of the substrate was varied from 0.1 to 2.5μm, and the current density of electrodeposition ranged from 1 to 7A/dm2. Tension testing was carried out at a constant tensile rate of 5mm/min. It was found that the adhesion of the film relative to substrate tension increased with increasing surface roughness. Dependence of adhesion on current density was not so marked, but higher current densities resulted in somewhat better adhesion. The presence of diamond grit in a deposited film increased the adhesion of the film. This is attributed to a retardation of film division due to the grit having the effect of a barrier to crack extension. Film separation or division occuring during tension tests was classified by appearance into three patterns.
Using data from a previous paper and such physical properties of organic reagents as melting point, boiling point, density, molecular weight and refractive index, as obtained from handbooks, the relationships between physical properties and the inhibiting effects of various organic reagents on the dissolution of aluminum in 1, 1, 1-trichloroethane (CCl3CH3) were subjected to correlation analysis, and the choice of inhibitor was investigated from the standpoint of physical properties. The results are summarized as follows: 1) In the case of ethers and esters, the inhibiting effect increased with melting point, boiling point, molecular weight (number of carbon atoms) and density. 2) In the case of phenols, alcohols, nitrocompounds, amines, ketones, nitriles and amides, physical properties had no influence on the inhibiting effect. 3) In the case of monohydric alcohols, contrary to the result described in 1) above, the inhibiting effect had a tendency to decrease with increasing boiling point, molecular weight and density, that is, methyl and ethyl alcohols with a small molecular weight had a large inhibiting effect. 4) The refractive indexes of the organic reagents used had no influence on the inhibiting effect.
Effects of complexing agents and ammonium ion on physical properties of electroless Ni-P films were systematically studied as a function of bath pH using citrate and glycine baths, with and without ammonium sulfate. The deposition rate and the phosphorus content of Ni-P films were strongly influenced by the species of complexing agent and the presence of ammonium ion in the bath. The physical properties of Ni-P films, such as deposition rate, saturation magnetization and specific resistance were discussed as a function of phosphorus content. Internal stress of Ni-P films, however, could not be determined as a function of phosphorus content.
The relation between the defects in the abraded layers resulting from the grinding, lapping and polishing of Si wafers and the break down phenomena of devices were investigated. The poly crystalline layer, mosaic layer, and crack layer defects caused by grinding had a strong influence on break down voltage. Moreover the presence of dislocations in these layers, induced by lapping, also caused soft break down phenomena. The layers treated by polishing, however did not influence device break down characteristics.