Investigation of tribological and corrosion performance of electroplated hard chromium coating on 17-4 PH steel.

This article focuses on the tribological and corrosion performance of electroplated hard chromium coatings applied to 17-4 PH stainless steel, commonly used in nuclear reactor fuel handling systems. The study found that the 35 µm thick chromium coating exhibited strong adhesion to the substrate, with critical scratch failure loads of 2.85 N (Lc1) and 11.5 N (Lc2), and no adhesive failure up to 30 N. Reciprocating dry sliding tests against AISI 440C steel balls showed that the coefficient of friction (COF) decreased with increasing load but increased with sliding frequency, while wear rate remained low up to a critical load of 7 N before rising sharply. Wear mechanisms involved work hardening, cohesive delamination, and three-body abrasion, with corrosion testing in 3.5 wt% NaCl solution revealing a low corrosion rate (9.2 × 10⁻³ mils per year) and homogeneous corrosion without pitting. These findings provide insight into the coating's durability under high contact pressures relevant to nuclear reactor applications.