Effect Of Binary Rare Earth Compounds On Microstructure And Tribological Properties Of Plasma Sprayed Ti-Al/WC Cermet Composite Coatings

Owning to low density,high-quality high-temperature mechanics,and oxidation resistance and so on,Ti-Al based alloys are hailed as one of the most valuable new lightweight alloy materials in the contemporary era.But the Ti-Al alloy is high brittleness and poor wear resistance,which was greatly limited wide application.Ti-Al/WC ceramics coating is deposited on the surface of 45 steel by plasma spraying equipment,which can effectively enhance the surface strength,hardness and wear resistance of parts.In order to compare a comparative experiment on the performance of the unit and binary rare earth oxides,two kinds of unit rare earth oxides?CeO₂ or Y₂O₃?with the best addition content were selected.This paper discusses the modification effect of binary rare earth oxides on the structure and tribological properties of coatings compared with monobasic rare earth oxides by the scanning electron microscope with energy spectrometer,micro hardness tester,X-ray diffraction and universal tension meter to test the microstructure of the coating.The specific findings are summarized as follows:?1?According to the screening test of two kinds of unary rare earth oxides,the modification of the coating is the best when adding 2%CeO₂ or 6%Y₂O₃.For example,high degree of fine grain strengthening,hardness,porosity and bonding strength are greatly improved.?2?Through comparative experiments,it can be concluded that the addition of binary rare earth oxides is better than unit rare earth oxides in modifying the coating structure.After being modified with binary rare earth,the surface structure of the coating changed from uneven to smooth;A large number of pores,voids and cracks in the tissue disappeared and became uniform;Dense mechanical bonding becomes stronger chemical bonding and partial metallurgical bonding.The porosity of the coating structure is reduced from 30.1%to 7.16%,and the residual stress is reduced from the maximum 364.6 MPa to 225.3 MPa,a drop of38.2%.?3?The wear resistance of the coating has been improved under the synergistic modification of binary rare earth oxide.The generated hard phases such as W₂C,SiC,NiCr,CrAl,TiAlC,TiC,etc,which greatly improve the hardness?753 HV?of the coating itself.The average friction coefficient of the coating has been reduced from 0.729 to 0.386.The wear rate was reduced by 85.3%in the same wear time.And the form of wear has also changed dramatically,from severe adhesion and fatigue wear to slight abrasive wear.This greatly improves the wear resistance,thereby extending the service life of parts.