最新色国产精品精品视频,中文字幕日韩一区二区不卡,亚洲有码转帖,夜夜躁日日躁狠狠久久av,中国凸偷窥xxxx自由视频

Thick gold material was fabricated in cyanide-free chloroauric acid solution by bipolar pulse reverse technique, influence of forward and reverse current density and duty cycle on the morphology and microstructure of gold deposits were studied and discussed. Results showed that when forward current density increased from 2.25 A/dm2 to 3.75A/ dm2, grain sizes became smaller and gold particles stacked more compact, but overhigh forward current density lead to surface fluctuation and decreasing of gold deposits flatness; While when reverse current density increased from 6 A/ dm2 to 12A/ dm2, grains became larger and structure loosen. Cathodic overpotential would increase when forward duty cycle increased from 20% to 60%, thus refining the gold deposits，grain sizes became smaller, but cracks would appear if forward duty cycle increased too much; While pores appear and deposits grew thinner and became crisp gradually when reverse duty cycle increased from 10% to 40%. By calculating the texture coefficient, gold deposits showed a preferred orientation along (111) and (222) plain under higher cathodic overpotential; while（200）plain was preferred under lower cathodic overpotential.