Characterization of Cr–Ni multilayers electroplated from a chromium(III)–nickel(II) bath using pulse current

Role of nickel undercoat and reduction-flame heating on the mechanical properties of Cr–C deposit electroplated from a trivalent chromium based bath

“…Contrary to the hardness variation of Cr-C deposits, the hardness of asplated Ni undercoat was slightly decreased from 380 Hv to 320 Hv after flame heating for 1 s. From the results of our previous study [12,13], we found that the as-plated Ni undercoat has a nano-sized crystalline structure. Thus, slight decrease in the hardness of as-plated Cr-C deposit after flame heating would be attributed to the softening effect of recrystallization and grain growth.…”

“…The surface of the steel substrate was mechanically ground with 1000 grit emery, pickled in 50 vol.% HCl solution at 50°C for 15 s, cleaned with deionized water, dried with an air blaster and then prepared for Cr-C electroplating. The Cr-C deposits were electroplated in a plating bath containing 0.8 M CrCl 3 6H 2 O as the main metal salt, urea as a complex agent and a small amount of buffer salts to maintain a pH value of 1.1 [12,13]. The Cr-C deposit with a thickness of ca.…”

Role of carbon in the chromium deposit electroplated from a trivalent chromium-based bath

“…Electroplating was conducted in a typical electrochemical three-electrode cell equipped with a potentiostat/galvanostat (EG&G. Model 263 A). The Cr-C deposits were obtained from a bath consisting of 0.8 M CrCl 3 .6H 2 O, with urea used as a complexing agent, and a small amount of buffer salts added to maintain the pH at 1.1 [10]. The bath temperature was kept constant at 30 ± 1°C.…”

Mechanical properties of Cr-Cu coatings produced by electroplating

“…Hard chromium coatings have advantageous properties such as high hardness, low coefficient of friction, high wear and corrosion resistance [1][2]. Electroplating is still widely found used to deposit chromium coating because this technique is simple and inexpensive.…”

“…Cu is a cheap and soft metal which has attracted many attentions for use as the upper layer of the hard chromium coatings. Laminated structures of coating materials have attracted many attentions because such structures can be used to modify the surface properties [2]. Besides to reduce the tensile stress, the existence of soft metal may be used a sacrificial in the fasteners to fulfill the void in order to block the gas/oil leakage.…”