Study On The Ceramics/Metal Thermal Barrier Coatings Piston

Based on the idea of low heat rejection, this paper gives a method of developing a new-type Al-piston which is called ceramics/metal thermal-barrier type gas engine piston to increase the piston's heat-resistant split characteristic, reduce its temperature and the loss of thermal, and improve the efficiency of thermal engine. The essential is to introduce the concept of Functionally Graded Materials(FGMs) into thermal-barrier coatings(TBCs) to form ceramic/metal gradient TBCs. Theoretical analysis, numerical count and experimental researches on ceramic/metal gradient TBCs are studied systemically in this paper.The material and structure of piston surface TBCs are given by combining material characteristics and optimizing design. They are composed of base body coatings, pure metal (Ni) coatings, ceramic/metal gradient coatings and pure ceramics coatings (ZrO2+MgO), the NiCrCoAlY and ZrO2 which constitute gradient coatings form cohesive coatings.Theoretical calculation and experimental validation have been done in order to experiment the gradient mitigation of remainder stress of piston surface TBCs, and the results are correct.In order to realize application type study, a fixing engine experiment of new-type piston is carried through. Based on this, the associative way of the coatings is analyzed by allographical and sterographical microscope, scanning electronic probe and energy analysis instrument. The result indicates that chemical bond between the alumina and nickel alloy is formed, at the same time, there are many kinds of associative ways such as mechanical, physical and diffused in prepared gradient coatings. Because of the formation of chemical bond and gradient technology, the cohesive intensity of TBCs is greatly improved. A new way is given to solve the reliability of ceramic/metal FGMs piston coatings.