抄録
Silver deposits obtained from cyanide bath with various addition agents were studied by electron diffraction analysis and also by photomicroscopy to elucidate the characteristics of the crystal structure of bright deposit formation.
Addition of inorganic sulfur compounds such as, Na2S2O3⋅5H2O and KSCN resulted in a semi-bright deposit, however, no preferred orientation of the crystals was observed in the deposit.
Organic sulfur compounds, such as thiourea, allyl thiourea, phenyl thiourea, allyl isothiocyanate, mercapto-benzimidazole, mercapto-benzothiazole, etc., gave rise to bright deposits with a moderate or strong preferred orientation of crystal.
Organic unsaturated compounds, such as coumarin, heliotropine, etc., used as effective brightener in Zn or Cd cyanide bath, produced a rough and matte deposit without preferred orientation of crystal.
It was found that there was no direct relationship between the degree or type of preferred orientation and the brightness of the surface.
Addition agents in the Ag cyanide bath seemed to make the deposit bright and smooth due to the fine grain formation rather than the preferred orientation of crystal.
