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Volume 44, Issue 9
Displaying 1-9 of 9 articles from this issue
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Michihiro KHONO, Masaru IKENAGA, Hiroshi ICHIMURA1993 Volume 44 Issue 9 Pages 708-714
Published: September 01, 1993
Released on J-STAGE: October 30, 2009
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Hiroyuki KANEKO1993 Volume 44 Issue 9 Pages 715-721
Published: September 01, 1993
Released on J-STAGE: October 30, 2009
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Eiichi NARITA1993 Volume 44 Issue 9 Pages 722-727
Published: September 01, 1993
Released on J-STAGE: October 30, 2009
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Osami SERI1993 Volume 44 Issue 9 Pages 729-731
Published: September 01, 1993
Released on J-STAGE: October 30, 2009
JOURNAL FREE ACCESSWhen aluminum specimens are cathodically polarized in a 1%NaCl solution whose pH has been ajusted to 1 by the addition of HCl, formation of pitting cavities over the aluminum surfaces is observed. It was found that the density of these cavities is considerably greater with aluminum specimens containing 273ppm of iron than with those containing only 1ppm. This is atributed to the presence in the former of finely dispersed intermetallic particles which provide preferential sites for the hydrogen evolution reactions during cathodic polarization. Due to the preferential reduction of protons and water, local pH around the particles increases during cathodic polarization and this, in turn, leads to local attack over the aluminum matrix surrounding the intermetallic particles and eventual formation of the pitting cavities.View full abstractDownload PDF (874K) -
Shozo MIZUMOTO, Hidemi NAWAFUNE, Noriyuki NISHIKAWA, Yasuhito KOHASHI1993 Volume 44 Issue 9 Pages 732-736
Published: September 01, 1993
Released on J-STAGE: October 30, 2009
JOURNAL FREE ACCESSIn situ monitoring of electroless nickel plating baths using sodium hypophosphite as a reducing agent was investigated by FTIR ATR spectrometry.
Basic bath composition was NiSO4·6H2O 0.1mol/L, C6H5O7Na3 0.2mol/L, NaH2PO2·H2O 0.2mol/L and Na2HPO3·5H2O 0.2mol/L (pH 8).
Linear relationships were obtained between the absorbance of the characteristic absorption bands and the concentrations of hypophosphite, phosphite, citrate and sulfate. In continuously used baths with large accumulations of phosphite and sulfate, the ATR spectra of hypophosphite, phosphite and sulfate overlapped, but even in these cases compositions could be determined with sufficient accuracy by curve fitting.
This constitutes a simple, rapid procedure that requires no dilution, separation or other pre-treatment, and was applied to the in situ monitoring of electroless plating baths with satisfactory analytical results.View full abstractDownload PDF (606K) -
Masaharu MOTONE, Yasuo NISHIMURA, Minoru MIZUHATA, Keisuke OGURO, Hiro ...1993 Volume 44 Issue 9 Pages 737-741
Published: September 01, 1993
Released on J-STAGE: October 30, 2009
JOURNAL FREE ACCESSThe effects of such bath conditions as reducing agent concentration, Ni salt concentration and plating temperature on the rate of electroless Ni plating by the reducing agent permeation method were examined.
At the initial nucleus formation stage, it was supposed that the mutual diffusion of BH4- and Cl- through the membrane was the rate determining step and the initial nucleus formation rate was proportional to the 0.2 power of NaBH4 concentration and NiCl2 concentration. The activation energies of the diffusion coefficients of both anious were calculated to be 4.57kJ/mol.
At the Ni growth stage, it was estimated that in addition to the nutual anion diffusion, Ni diffusion was also the rate determining step.
The rate of Ni growth was proportional to the 0.3 power of the NaBH4 concentration and the 0.7 power of the NiCl2 concentration. The activation energy of the rate constant was calculated to be 3.90kJ/mol. The rate of Ni growth can be controlled by these kinetic parameters.View full abstractDownload PDF (1058K) -
Effect of Additives in Organic Acid Bath of Electroless Solder Plating; Studies of Complexing AgentsMakoto YUASA, Katsuyuki MATSUMOTO, Akihiro MASUDA, Tomokazu KUMEUCHI, ...1993 Volume 44 Issue 9 Pages 742-747
Published: September 01, 1993
Released on J-STAGE: October 30, 2009
JOURNAL FREE ACCESSThe effect of additives (i.e. complexing agents) to organic acid baths in obtaining solder plating films at 0.8 to 0.9 of Sn/(Sn+Pb)-molar fraction {0.6 to 0.9 of Sn/(Sn+Pb)-weight fraction} by displacement plating was investigated by physicochemical methods. An effective plating film was obtained from a basic bath composed of metal salts of Sn and Pb, an organic acid, a first complexing agent (thiourea, abbreviated as TU) and a surface active agent (laurylpyridinium chloride), and the molar fraction of Sn/(Sn+Pb) was 0.50 {the weight fraction of Sn/(Sn+Pb) was 0.36}. It was found that the effective first complexing agent in the compounds containing sulfar had a C=S group such as TU and its derivatives. The formation of Sn whiskers on the plating film was depressed by adding a second complexing agent (glycine) to the bath. The working efficiency (deposition rate and lifetime) of baths with glycine was similar or superior to those without glycine.View full abstractDownload PDF (2141K) -
Ming LI, Masamichi KOWAKA1993 Volume 44 Issue 9 Pages 748-752
Published: September 01, 1993
Released on J-STAGE: October 30, 2009
JOURNAL FREE ACCESSSmooth, bright films containing 12-48wt% iron, 32-70wt% nickel and 5-40wt% tungsten were obtained from 1-hydroxyethane-1, 1-diphosphonic baths. The tungsten content of the alloys increased with increases in the concentrations of potassium tangstate and ferrous chloride in the baths, but was unrelated to current density. Vickers hardness rose from 400 to 800 when tungsten content increased from 5wt% to 40wt%. The results of X-ray diffraction (Cu-Kα) showed that the alloy is amorphous when the tungsten content exceeds a critical value, which is lowered from 30wt% to 20wt% when the iron content of the alloy is increased from 12 to 48wt%.View full abstractDownload PDF (574K) -
Yutaka YAMADA, Osami SERI, Kosuke TAGASHIRA, Koji NAGATA1993 Volume 44 Issue 9 Pages 753-756
Published: September 01, 1993
Released on J-STAGE: October 30, 2009
JOURNAL FREE ACCESSThe pitting corrosion of copper in cold water containing inhibitors composed of nitrilotris methylene triphosphonic acid (ATMP), benzotriazole (BTA) and zinc sulfate (ZnSO4) has been studied using immersion tests and electrochemical measurements. The results obtained are summarized as follows: 1) Pitting corrosion was influenced by SO42- rather than Cl-. 2) The presence of both SO42- and Cl- in ATMP+BTA solution was conducive to pitting corrosion. 3) In ATMP+BTA solutions containg SO42-, breakdown potential Eb was linearly dependent on Cl- and is thought to affect the critical breakdown potential.View full abstractDownload PDF (1387K)
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