Wear behavior of corroded Al-Al2O3 composite coatings prepared by cold spray

Al-based Al2O3 particle-reinforced composite coatings were fabricated onto steel substrates by low pressure cold spray technology (LPCS). The content of Al2O3 in the feedstock was 25 vol%. The microstructure of the coating was characterized using scanning electron microscopy (SEM) and X-ray diffraction. It was found that the composite coating contained a uniform distribution of Al and Al2O3 particles without evidence of oxidations. The coating exhibited a very dense microstructure with strong adhesion to the substrate. Neutral salt spray (NSS) and electrochemical tests revealed that the Al-Al2O3 composite coating was still efficient in providing a corrosion protection for the steel substrate, although a porous top layer formed in the coating after 960 h corrosion. Corroded coatings were then subjected to dry sliding wear tests from which the wear tracks were observed. The results indicated that increased damage accumulation by corrosion reduced cohesive strength between particles and resulted in high volume losses and poor worn appearances.