• Journal of the Korean institute of surface engineering
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• v.37 no.2
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• pp.92-98
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• 2004

The current efficiency and the microstructure of the trivalent Cr deposits plated in flow cell system were investigated according to additives in sulfate bath and current density. The current efficiency of the deposits plated in the formic acid complexed bath was noticeably higher than that of the deposits from glycine complexed bath. The current efficiency of the deposits from the complexed baths with boric acid buffer increased linearly with current density in the range of 60-100 A/dm$^2$, while that of the deposits from the baths with both Al sulfate and mixed buffers increased parabolically with current density. The nodular crystallite size of the deposits increased with current density, and the deposits plated in low current density region had relatively smooth surface appearance with fine grains. The structure of the deposits from the complexed baths with boric acid buffer changed from amorphous structure to crystalline one with strong (110)peak with increasing current density. The deposits from the baths with both Al sulfate and mixed buffers had generally amorphous structure.

• Journal of the Korean institute of surface engineering
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• v.36 no.1
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• pp.48-58
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• 2003

This paper will present an overview of toxicity of hexavalent chromium as well as effort for its replacement by a wide spectrum of alternative materials and technologies. Cr-based materials such as trivalent electrodeposit will be one of strong candidates for hard chromium by surface modification of its surface hardness. Ni-base alloy deposits has proved its application in specific mold for glass. HVOF has been studied in aircraft and military sector. There are still under way of development for commercially available alternatives. To date, no single coating has been identified as universal process as comparable to conventional hard chromium electroplating.