Study On Surface/interface Characteristics And Thermo-mechanical Properties Of Ni-based Coating By Plasma Cladding

Plasma cladding composite coatings effectively combine advantages of the self-fluxing metal and the ceramic particles,so they have excellent surface performances.Due to its properties of high strength,high temperature resistance,good wear resistance and good toughness,the plasma cladding composite coatings have been widely used as mechanical parts and components in the special and harsh field such as machinery manufacturing,heavy metallurgy,nuclear engineering,mine exploration and gasoline drilling et al.Surface engineering technology could modify coatings under ecomomical condition,it has been a research hotspot for cladding a high property coatings on the mechanical parts and components which are worked in extreme environments.In this research,Ni matrix composite coatings reinforced by in-situ Ti(C,N)and WC particle with different contents were fabricated by tungsten-inert gas melting process employing a proper amount of alloy powder(Ni60?Ti?WC powders).The relationship between microstructure ? distribution of strengthening phases and wear resistance ?mechanical properties were analyzed systematically.At the same time,the factors and rules influencing microstructure and properties were investigated.The Ni-based coating reinforced by WC particle was prepared by employing Ni60+WC powders.The microstructure and properties of Ni matrix composite coatings reinforced by WC particle with different contents(the WC content respectively is 0%,10%,20% and 30%)were analyzed.Then,the effect of longitudinal magnetic field was applyed in cladding process.Compared with non-magnetic condition,the variation tendency of microstructure and element distribution were summarized.It is concluded that: when magnetic field intensity is 38 mT,microhardness and wear resistance of the coatings are improved significantly;The shape of W-rich carbides is transferred from block mixed with cluster to crumbling snowflake structure.By means of altering the feeding gas(argon gas)into nitrogen and adding Ti powder(the Ti content respectively is 10%,20% and 30%)in the metal based compound powder,the Ni-based coating reinforced by in-situ Ti(C,N)was formed under the effect of high temperature plasma arc;the microstructure and properties of composite coatings were analyzed at the effect of both the internal precipitation method and the external adding method.A number of bilayer models were established via MS to simulate the process of plasma cladding,analyzing the variation tendency of interfacial energy and atomic diffusion at different temperature in relevant models.Compared with the data of prior mechanical property test results,the dynamic change rule of m icrostructure was obtained.