STUDY OF THE EFFECT OF HEALING SURFACE DEFECTS DURING DEPOSITION OF NITRIDE COATINGS ON TITANIUM ALLOY PARTS

ZrN, (Zr, Hf) N, and (Zr, Ti) N coatings were deposited on a Ti-6Al-4V titanium alloy substrate. Scanning and transmission microscopy showed that a defective layer 2-3 μm thick is formed during grinding of the titanium alloy. Microcracks and other surface defects are observed in this layer. Healing (sealing) of cracks and other surface defects is observed during coating deposition. It was found that crack sealing begins during ion etching and is completed during deposition of the adhesive and wear-resistant coating layers. Thus, the coating not only increases the surface hardness and wear resistance of the product, but also allows to some extent reduction of defects in the surface layer of the substrate.