Silicon carbonitride ceramic surface-modified nanoporous aluminum alloy by preceramic polysilazane precursor for surface strengthening

摘要

Preceramic polysilazane precursor is simply coated on the anodized 7003 alloy and pyrolyzed at 400, 500 and 600 °C, respectively to form a silicon carbonitride ceramic film. The scanning and transmission electron microscopic images show that silicon carbonitride film can be detected on the surface of the anodic aluminum oxide compactly, representing a multilayer structure with the films of SiCN, SiCN with anodic aluminum oxide (AAO) layer and 7003 alloy substrate. The wear test is built-up by a stainless steel velvet head with reciprocating movement. After wearing in 2.176 km, the wear rate of the SiCN coated 7003 alloy pyrolyzed at 600 °C is about 0.003%, extremely lower than that of the anodized 7003 alloy, 0.023%. The average surface hardness and indentation modulus of elasticity can achieve higher than 6 GPa and 85-90 GPa that are twice higher than those of the anodized 7003 alloy.