Tribological Properties of Plasma Sprayed Fe_3Al-Al_2O_3 Graded Coatings

摘要

Fe_3Al-Al_2O_3 graded coatings were produced from a series of Fe_3Al/Al_2O_3 composite powders with different compositions on low carbon steel substrate using PLAXA1R plasma spraying equipment. Friction behavior and the wear resistance of the corresponding Fe_3Al-Al_2O_3 graded coatings have been investigated under different loads. Tests were carried out using an MRH-3 high speed block-on-ring wear test machine, in linear contact sliding under dry conditions against hardmetal, at a sliding velocity of 1.57 ms~(-1). Wear rates under different loads were measured and the friction coefficients recorded. SEM analysis is carried out to identify the wear mechanisms. The results show that the gradient distribution of coating composition caused different wear resistance and wear mechanisms of the coatings. The wear rates of the coatings are different along the depth of the coating, and the surface of coatings with pure Al_2O_3 does not have the best wear resistance. The friction coefficients are also different under different loads. The failure types of plasma-sprayed Fe_3Al-Al_2O_3 graded coatings in linear contact sliding under dry condition included: plastic deformation, adhesive wear, loosening of ceramic particles, crack nucleation and propagation, and brittle fracture.