Effect Of Preparation Process0f TiN-based Composite Coatingon Structure And Properties

Titanium nitride is a ceramic material with high hardness and high melting point.The titanium nitride coating is used in many fields because of its good wear resistance.In this paper,sub-micrometer Ni powders were mixed with PEEK(polyether-ether-ketone)powders to prepare coated composite powder by spray drying,then the two kinds of coated composite powder mixed with Ti powders,respectively,in varying proportions.TiN-Ni/PEEK composite coating were fabricated by plasma spraying those composite powders.The morphology and phase of composite powders and coatings were analyzed.Wear and abrasive resistance of composite coatings with PEEK addition were respectively tested and compared with TiN coatings,respectively.Study results showed that:(1)The Ni/PEEK composite powder made of ball-milled nickel powder has better fluidity and smaller specific surface area,and the heating during the spraying is more uniform,and the degree of oxidation and pollution is lower.(2)The contact angle between Ni and PEEK is less than 90°,so the wettability between Ni and PEEK is good,and the bond between Ni and PEEK will not cracked due to the interfacial tension.The interface between Ni and TiN has no microcracks and the two phases are well-integrated.(3)The TiN droplet spreads directly on the surface of the substrate after being impacted by the matrix and sputters.The TiN droplets are tightly bonded to the substrate and micro cracks appear on the surface of the TiN droplets.The Ni/PEEK droplets spread flat on the substrate after striking the matrix.It was opened,and the sputtering state during impact on the collective was not obvious.(4)The best power for preparing composite coatings is 24 KW.When Ni and PEEK were added to the TiN coating,the hardness of the coating decreased.The wear failure mechanism of the coating was fatigue wear.Compared with TiN coating,TiNNi-PEEK composite coating had a higher wear and abrasive resistance.The optimum Ni/PEEK content for preparing the composite coating is 40 wt%.(5)The Ni/PEEK composite powder prepared by spray granulation was heated by the flame of plasma spraying to be used as a compound in spraying to prepare the composite coatings,compared with the Ni/PEEK prepared by spray granulation was directly used as a spray coating to prepare the composite coating,it had a higher wear and abrasive resistance.