Effect of nitriding pre‐treatment on the tribocorrosion behavior of physical vapor deposition‐coated tool steel

Abstract

AbstractCr‐Al‐Ti‐B‐N hard coating is deposited onto the AISI D2 cold‐worked tool steel by means of a hybrid physical vapor deposition (PVD) technique. The effect of plasma nitriding pre‐treatment on the tribocorrosion behavior of the hard‐coated tool steel is investigated using a ball‐on‐disc sliding wear tribometer equipped with an electrochemical testing set up. Tribocorrosive characteristics are analyzed by optical and scanning electron microscopy, 3D surface profilometry, and open circuit potential (OCP) measurement. The coefficient of friction and OCP varies depending on the degree of damage to the hard coating, such that the point at which the substrate is first exposed can be identified by these measurements. The plasma nitriding pretreatment increases the surface hardness significantly and, therefore, the adhesion of the PVD hard coating to the substrate material. As a consequence, the material's wear resistance is enhanced and its durability against tribocorrosion is improved.