Experimental Research on Hard and Crack-Free Electrodeposited Chromium Coatings

Abstract:

In order to eliminate cracks in the chromium coating, a novel method named flexible extrusion assisted chromium electroplating was proposed. The bright and crack-free chromium coatings were electrodeposited by using the perturbation and extrusion of hard and insulating particles. The prepared deposits were characterized by scanning electron microscope (SEM) and three-dimensional topography. The testing results showed that the surface was very smooth and there was no micro cracks in the coating. Micro hardness of the electrodeposited layer was also tested. It was confirmed that the chromium coating electrodeposited with rotating cathode in hard particles had high micro hardness as to 850HV and the micro hardness could be controlled by the process parameters. The rule of the micro hardness was concluded by analyzing current density and rotating speed. In addition the results of salt spray test and electrochemical polarization curve showed that the coating deposited by new method had higher corrosion resistance than that by traditional method.

• Periodical: Advanced Materials Research (Volumes 1044-1045)
• Pages: 47-52
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1044-1045.47
• Online since: October 2014
• Authors: Xue Lei Li*, Xiao Hang Liu, Hao Bin Tian, Wen Jing Yuan
• Keywords: Crack-Free, Electrodeposit, Flexible-Extrusion, Hard

References

[1] M. Kohl, A process for the direct or indirect electrodeposition of a highly corrosion resisting crack free technical hard chromium plating layer, UK Patent GB2236763A, (1991).

[2] J.C. Saiddington, G.R. Hoey, Crack-free chromium from conventional plating baths, in: the 61st Annual Technical Conference, (1974).

DOI: 10.4095/300211

[3] M. Heydarzadeh Sohi et al, Comparative tribological study of hard and crack-free electrodeposited chromium coatings. Journal of Materials Processing Technology, 138(2003) 219-222.

DOI: 10.1016/s0924-0136(03)00075-x

[4] Imaz, N.; Garcia-Lecina, E.;  Diez, J. A. et al, Chemometrics applied to functional chromium electroplating by pulse plating techniques, Transactions of the Institute of Metal Finishing, 90(2012) 259-266.

DOI: 10.1179/0020296712z.00000000046

[5] Imaz, N., Ostra, M., Vidal, M. et al. Corrosion behaviour of chromium coatings obtained by direct and reverse pulse plating electrodeposition in NaCl aqueous solution. Corrosion Science: 78(2014) 251-259.

DOI: 10.1016/j.corsci.2013.10.005

[6] Leisner, P., Belov, I. Influence of process parameters on crack formation in direct current and pulse reversal plated hard chromium. Transactions of the Institute of Metal Finishing. 87(2009) 90-96.

DOI: 10.1179/174591909x424078

[7] Makarov, I., Chen, J. ,  Yurasovskaya, E. et al, Effect of electrolyte additives on microstructure and properties of electroplated chromium coatings. Canadian Metallurgical Quarterly, 50(2011) 153-165.

DOI: 10.1179/000844311x12949291727853

[8] Schreiner, H.; Raub, Ch.J. Studies of the Production of Crack-free Stress-Relieved Hard Chromium Coatings. MO Metalloberflache Beschichten von Metall und Kunststoff,  33(1979) 464-474.

[9] H Runan, C Qisong, Practical Chromium Plating Technique, National Defense Industry Press, China, ( 2005).