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In this paper, bi-layer (SiC + diamond) coatings were synthesized on 0.8-mm-diameter cemented carbide micro-end mills. The influences of SiC interlayers and diamond coatings on the morphologies, phase composition and fracture strength were investigated. The cutting performance of the bi-layer (SiC + diamond) coated tools was validated by dry cutting of aluminum alloys. The results indicated that the binder Co reacted with SiC to form cobalt silicides (i.e., Co 2 Si and CoSi), suggesting that the SiC interlayer suppressed the deleterious effects of Co, successfully. Neither the presence of the SiC interlayer nor the bi-layer coatings reduced the fracture resistance of the tools. The workpieces had a better surface finish after being cut by the coated tools than those cut by the uncoated tools. This result indicated that the bi-layer (SiC + diamond) coated tools exhibited better cutting performance than the uncoated tools. Thus, SiC interlayers were demonstrated as a suitable option for adherent diamond coatings on the cemented carbide components and cutting tools. [ABSTRACT FROM AUTHOR]

SiC films were synthesized on WC-Co substrate as interlayers for improving the adhesion of diamond coatings. The influence of the substrate temperature on the SiC films was investigated. The results showed that when the temperature was 600 °C, the film was formed of loose agglomerates piled up by SiC nanoparticles. As the temperature increased to 850 °C, shell structure composed of SiC particles and graphite replaced the agglomerates. When the temperature exceeded 950 °C, flower-like SiC clusters and graphite spherical particles coexisted in the surface, and Co 2 Si particles embedded at the SiC/substrate interface. SiC films deposited at 600 °C, 850 °C and 950 °C were typically used as interlayer for diamond deposition. The coatings exhibited the similar nano-diamond structure. However, the diamond coating on the interlayer produced at 850 °C possessed the best adhesion; and the diffusion of Co was effectively inhibited by SiC interlayer which would not interfere with the process of diamond deposition. [ABSTRACT FROM AUTHOR]