Preparation Of TiN-PEEK Composite Coating By Plasma Spraying And Research On Its Wear And Corrosion Resistance

At present,application and failure of composite materials in the complex service conditions has been included in the national "Twelfth Five" science and technology development planning.Design and production of low cost,high strength,high hardness,wear resistance,corrosion resistance of the composites have higher economic value;the corrosive wear mechanism of the composites was studied with high scientific significance.This subject adopts the method of reactive plasma spraying on the surface of the sample to prepare thick composite coating with nano TiN as matrix and PEEK as second phase.The study of composite coating preparation,process optimization,wear resistance,resistance to corrosion,the relationship between wear and corrosion was made by using electrochemical workstation,SEM,EDS,XRD,wear testing machine,corrosion-wear test device,and so on.The results show that:(1)The composite coating prepared by dual synchronous powder feeding had the most compact organization,fewer impurity content,undecomposed and dispersed PEEK phase;the optimized process parameters were: power was 21 KW,the distance of gun was 100 mm,and the value of second feeding was 60 mm.(2)With the increase of load,reduced the friction coefficient and increased the wear volume of TiN-PEEK composite coating.the friction coefficient of TiN-PEEK composite coatings was lower than TiN coating always.under the experimental condition,the wear mechanism of TiN-PEEK composite coating was abrasive wear and fatigue wear.with change of the load,the wear mechanism of composite coating changed.the main wear mechanism was abrasive wear at low load,abrasive wear and fatigue wear were concomitant at medium load,the main wear mechanism was fatigue wear at high load.(3)TiN-PEEK composite coating had higher Ecorr,smaller polarization current,better corrosion resistance than TiN coating.corrosion process of TiN-PEEK composite coating was divided into two stages,corrosion began to 43 h was the initial stage of corrosion,the equivalent circuit was R(Q(R(QR))),43 h to 172 h was the later stage of corrosion,the equivalent circuit was R(Q(R(Q(RW)))),the corrosion time of composite coating was 1.7 times of TiN coating,and the corrosion time of TiN was 102 hours.(4)Wear made corrosion potential of TiN-PEEK composite coating decrease,made corrosion current of polarization curve of TiN-PEEK increase,and promoted corrosion.Wear influenced initial stage of corrosion of TiN-PEEK composite coatings mainly in low-middle frequency range,effect of wear in the initial stage of corrrosion was less;during the later period of corrosion,Wear obvious accelerated corrosion.The amount of interaction between corrosion and wear and in the proportion of total weightlessness both increased,with the increase of corrosion time.The corrosive wear resistance of the composite coating was determined by the joint coordination of wear resistance and corrosion resistance.