Corrosion Properties of Ni60/WC Coating with Abrasion‐Resistant Microdimples Ablated by Nanosecond Laser

Abstract

Herein, the influence of laser‐ablated cracks in microdimples on the corrosion properties of Ni60/tungsten carbide (WC) coating is investigated. It is based on the dimension parameters of circular microdimples, which is optimized by unit and full‐size friction‐wear experiments for a textured plunger and sealed‐disk assembly element. The Poisson distribution is used to perform the statistical and characterization analyses of the microcrack defects on the surface of Ni60/WC coating with the circular microdimples ablated by the nanosecond laser. The key process parameters of laser machining in groups with a high and a low ratio of apparent microcrack are selected, and are compared with the nontextured group on the coating surface through immersion–corrosion and electrochemical–corrosion tests. It finds the high and low apparent‐microcrack groups under the action of static corrosion, and the coating has the similar corrosion behavior with the nontextured group. When apparent microcrack does not extend to the substrate, the nanosecond‐laser ablation of microdimples does not change the coating corrosion properties. Moreover, the corrosion properties of the coating are improved by laser ablation recrystallization. The experimental support is provided in the results for the application of microdimples on the surface of fracturing‐pump plunger coating in acidic environments.