Electroplating process of amorphous Fe-Ni-Cr alloy
(1. Department of Chemical Engineering, Xiangtan Polytechnic University,
Xiangtan 411201, P.R.China;
2. Department of Mechanical, and Electronic Engineering,
Guangdong University of Technology, Guangzhou 510090, P.R.China；
3. Department of Metallurgical Science and Engineering,
Central South University, Changsha 410083, P.R.China)
Xiangtan 411201, P.R.China;
2. Department of Mechanical, and Electronic Engineering,
Guangdong University of Technology, Guangzhou 510090, P.R.China；
3. Department of Metallurgical Science and Engineering,
Central South University, Changsha 410083, P.R.China)
Abstract: A novel process of electroplating amorphous Fe-Cr-Ni alloy in chloride aqueous solution with Fe(Ⅱ), Ni(Ⅱ) and Cr(Ⅲ) was reported. Couple plasma atomic emission spectrometry (ICP-AES), X-ray diffractometry(XRD), scanning electronic microscopy(SEM), microhardness test and rapid heating-cooling method were adopted to detect the properties of the amorphous Fe-Ni-Cr deposit, such as composition, crystalline structure, micrograph, hardness, and adherence between deposit and substrate. The effects of the operating parameters on the electrodeposit of the amorphous Fe-Ni-Cr alloy were discussed in detail. The results show that a 8.7?μm thick mirrorlike amorphous Fe-Ni-Cr alloy deposit, with Vicker's hardness of 530 and composition of 45%～55% Fe, 33%～37% Ni, 9%～23% Cr was obtained by electroplating for 20min at room temperature(10～30℃), cathode current 10～16A/dm2, pH=1.0～3.0. The XRD patterns show that there only appears a broad hump around 2θ of 41°～47° for the amorphous Fe-Ni-Cr alloy deposit, while the SEM micrographs show that the deposit contains only a few fine cracks but no pinholes.
Key words: amorphism; Fe-Ni-Cr alloy; electroplating; trivalent chromium; chloride