Abstract: Ceramic-coated cemented carbide cutting tools are prepare from aluminum alkoxide solution and carbide substrates by sol-gel route. The carbide substrates is coated with boehmite sol by dip-coating process and dried to get gel film. After the heat treatment at 1200℃,the coating with a thickness up to 10μm could be obtained without any macroscopic defect and showed good performance in turning medium carbon steel, which presented a novel and promising coating method for cutting tools. The results suggested that the coating convert to α alumina at about 1140℃ and sintered to relatively high density at 1200℃. The coating is polycrystalline and isotropic and there is in weak phase in the interface layer. It is found that cobalt diffused into the coating, which would be conductive to enhance the bonding strength between the substrate and the coating.

Key words: Al2O3, Coated tools, Cutting performance, Sol-gel route