The inherent contradiction between hardness and toughness in cemented carbide tools can be effectively addressed through the application of coatings,resulting in enhanced overall properties for coated cemented carbide tools.However,a single coating may not suffice to meet the demands of high-speed and dry cutting applications. This study aims to provide a reference for the design,application,and advancement of coated cemented carbide tools studying MT-TiCN single coating and an MT-TiCN/Al2O3 bilayer coating deposited onto WC-6Co substrates using chemical vapor deposition technology. A comparative analysis was conducted on the microstructure,hardness,adhesive strength,oxidation resistance,and tribological properties of the MT-TiCN coating and the MT-TiCN/Al2O3 coating,with a focus on the influence of the Al2O3 layer on these properties. The results indicate that the MT-TiCN/Al2O3 coating maintains good adhesive strength. In comparison to the MT-TiCN coating,the MT-TiCN/Al2O3 coating exhibits lower hardness,reduced oxidation weight gain,and improved oxidation morphology,alongside increased surface roughness,higher friction coefficient,and wear rate. While the Al2O3 layer significantly enhances the oxidation resistance of the MT-TiCN/Al2O3 coating,it simultaneously detracts from wear resistance,as the Al2O3 layer is prone to breakage and delamination under dry sliding conditions.
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