The effect of four complexing agents-sodium citrate, sodium malonate, glycine and diethylenetriamine-on electroless NiB plating using dimethylamine-borane (DMAB) as a reducing agent was studied. The deposition rate was influenced by the pH, DMAB concentration, and the complexing agent species. The B and C content of deposited films, in particular, was strongly influenced by the complexing agent species. The B content of film deposited from a sodium citrate bath in a pH of 6.5 and 003mol dm-3 DMAB concentration was the highest -5.41wt%-, while the C content was lower -01wt%-. The C content of film deposited from a diethylenetriamine bath at a pH 7.5 and the same DMAB concentration as given above was, in contrast, the highest -0.29wt%-, and the B content was lower -1.34wt%-. XRD results indicated that, in our study, as-deposited films showed an amorphous structure when the condition was such that the boron content was more than 2.5wt%. Such as-deposited films were crystallized by heat treatment at 300°C for 1hr. The lattice distance of Ni (111) was shifted from 0.2017nm to 0.2032nm, and the content of C was found to have increased.
Platinum-tin alloy plating in a platinum plating solution in the presence of potassium hexahydroxoplatinate and potassium stannate added was studied. Up to 100g/L tin was added to the bath, which contained 10g/L of platinum and its effect on deposit efficiency and alloy composition was analyzed. Based on this, the current efficiency was determined and found to decrease from 90% to 30% with the addition of tin from 5g/L to 10g/L to 15g/L. When more tin was added, current efficiency became about 40%. The codeposition of tin was about 30wt%. Deposits containing 15 to 25wt% of tin were observed to have in excess of 600Hv Vickers hardness. X-ray diffraction imaging determined that, with tin codeposition, platinum deposits were no longer oriented to (200) and the diffraction peak range were broadened.
We studied how impurities-Cr, Fe, Co, Ni, Zn, Ag, Cd and Sn-in electrolytes, prepared with recycled copper, affect surface morphology and mechanical properties, i.e., tensile strength and elongation-of electrolytic polycrystalline copper deposlts, 35μm thick. In additive concentrations of 0.001 to 10g/dm3, we found that Cr, Fe, Co, Ni, Zn and Cd are not introduced into copper deposits. In contrast, Ag and Sn were found in copper deposits at an Ag additive concentration exceeding 0.01g/dm3 and a Sn additive concentration exceeding 10g/dm3. Copper deposit morphology was characterized by the presence of large numbers of bumps surrounded by crystallographical planes and their (220) preferential orientation. For the Sn additive concentration of 10g/dm3, however, surface morphology consisted of fine semispherical bumps and an almost random orientation distribution. The tensile strength of copper deposits was found to depend strongly on copper crystallite size, independent of orientation.
The effects of zinc ions on the internal tensile stress in nickel deposits obtained from Watts-type baths were studied. The variations in the elastic deformation of the deposits was measured in situ using a resistance wire-type strain gauge placed on the reverse side of the copper electrode. Zinc ions were adsorbed by nickel hydroxide formed on and close to the electrode surface during nickel electroplating and codeposited as zinc oxide with nickel in the deposits. However, at a potential of less noble than-102V (vs Ag/AgCl sat. KCl), a part of zinc ions was electrically reduced to metallic zinc and codeposited with zinc oxide in the deposits. The amount of zinc oxide included in the deposits increased with an increase in the concentration of zinc ions in the plating solutions. The internal tensile stress in the deposits increased with an increase in the amount of the included zinc oxide and the increased tensile stress caused many cracks on the surface of nickel deposits.
The relationship between the ζ potential and the codeposition of hydrophobic CF (S) and hydrophilic TiO2 (A) particles have been investigated. The bath to which anionic and cationic surfactants were added in distilled water, acid copper sulfate baths, and Watts baths. The maximum ζ potential of CF (S) particles was +44 7mV and that the maximum potential of TiO2 (A) particies was +13 4mV in distilled water due to the adsorbance of cationic surfactant on particies. The minimum ζ potential of CF (S) particles was -510mV and that the minimum potential of TiO2 (A) particle was -150mV in deposition baths due to the adsorbance of anionic surfactant on particles. A codeposited coating was obtained in cases where the cationic surfactant was adsorbed do CF (S) particles. Such a codeposited coating was not obtained, however, in cases where the anionic surfactant was adsorbed on CF (S) particles. We further found that a codeposited coating was obtained in cases where both of the above surfactants were adsorbed on TiO2 (A) particles, the amount of codeposited TiO2 (A) particles obtained, however, was found to be less than that of the cationic surfactant adsorbed on CF (S) particles. In conclusion, we found that the behavior of codeposition turned out to be markedly different depending on the character of the dispersed particles involved.
The electrodepositon of Zn-iron-group metal binary alloys, which has been applied in the production of highly corrosion-resistant alloy-plated steel sheet, was conducted in sulfate baths. The current density-dependence of the alloy composition demonstrated a typical feature of an anomalous codeposition in sulfate baths. As the present authors reported previously, the alloy deposition behavior was divided with respect to the current density into four regions. The presence of thiocyanate (SCN-) ions in the baths changed the alloy deposition behavior both in lower current density region I where normal codeposition occurred with extremely poor current efficiency and in the region II where anomalous codeposition occurred with high current efficiency. The partial current efficiency of iron-group metal was found to increase in regions I and II. The boundary current density between these two regions, which was also known as the transition current density, was also found to increase. It was concluded that the catalytic action of SCN- ions served to explain well the changes in the electrodeposition behavior.
The rotational and translational states of Iron Pentacarbonyls (Fe(CO)5) were caluculated under supersonic molecular beam conditions. High-resolution infrared absorption spectra indicated that the rotational temperature of Fe(CO)5 in Ar buffer gas was 6K, that in Ne buffer gas was 9K, and He buffer gas was 14K. Time-resolved infrared absorption spectra indicated that velocity of Fe(CO)5 in Ar buffer gas was 1, 400ms-1, corresponding to Mach 4, and that in He buffer gas was 2, 700ms-1, corresponding to Mach 8.