Study On Properties Of Metal-Base Ceramic Composite Coatings Prepared By Arc Spraying

Ceramic coating is of great development prospect. Ceramic coating shows a extensive applications in many high technology fields including aviation spaceflight, energy electron, materials etc if we combine its wear, high temperature oxidation and corrosion resistance with ductility, workability, conduction and heat conduction of metal material. At present, main preparation methods for ceramic coating have been commonly used, chemical vapor deposition(CVD), physical vapor deposition(PVD), impulse electrode deposition and thermal spraying. Thermal spraying is an important surface engineering technology. Arc spraying is a branch of thermal spraying technologies and has the advantages of wide scope of adjusting chemical compositions, low price, convenience of field-work, compared with plasma spraying and HVOF.This paper studied on properties of carbide ceramic composite coatings, oxide composite coatings and nanostructured coatings. Surface Rockwell hardness, bonding strength, high temperature oxidation, wear, themal shock and porosity of the coatings were tested. The microstructure of arc sprayed ceramic composite coatings was investigated by X-ray(XRD), micrographs, scanning electron microscopy (SEM) and energy spectrum. The effects of composition in cored wire on properties of the coatings was studied. The results showed:(1) When containning Cr3C2+Ni cored wires were sprayed, the max bonding strength of the coating was 48MPa with a optimal Ni content-25%, not Cr3C2 phase in the coating investigated by XRD.(2) When containning Al2O3+TiO2 cored wires were sprayed, TiO2 could make the coatings denser and higher bonding strength. Rockwell hardness was increased from 45 to 62 with NiCr-Cr3C2 added. There were Al2O3 and TiO2 phase in the coatings investigated by XRD.(3) Nanostructured and conventional coatings were deposited by arc spraying. We founded that surface Rockwell of nanostuctured coating was in the same level compared with conventional coatings, bonding strength increased 1.5 times.A(4) This chapter researched the effects of spray distance on particle velocity and temperature with SprayWatch measurement. The particle temperature was between 1600C and 2800C, max particle velocity could reach 325m/s. The results could avail to good principle for the study of nanostructured coatings.