CCFL Functionally Graded Cemented Carbide (1/2)

Tungsten carbide, also called cemented carbide, is composed of hard phase WC and binder phase Co, which has higher hardness, strength and excellent wear resistance and has been widely used in metal cutting industries. In order to further improve the hardness and wear resistance of tungsten carbide cutting tools, in the actual production is often by adjusting the alloy binder phase content and add cubic carbides (such as TiC, TaC, Cr3C2, etc.) or the like by introducing coating technology (such as CVD chemical vapor deposition, PVD physical vapor deposition) higher in the cemented carbide substrate surface coated surface hardness, chemically more stable phase ceramic layer. However, there are some differences in the coefficient of thermal expansion and binding force between tungsten carbide matrix and coating layer, so the coating will crack and even peel off at work, which remarkably affects the using properties of tungsten carbide coated cutting tools and decreases the overall efficiency.

New functionally graded cemented carbide can effectively inhibit the formation and spreading of cracks to the substrate coating cracks and improve the reliability and service life of tungsten carbide cutting tools. From the component point of view, it can be divided functionally graded cemented carbide non-equilibrium carbon and nitrogen carbide. Unbalanced carbide or carbon, said carbon-poor carbide carburizing process can be prepared for two-phase drilling with carbide; The nitrogen-containing alloy can be divided according to the internal balance of nitrogen partial pressure difference between the pressure of the nitrogen balance in the environment can be achieved nitride, and nitrogen, and forming two distinct surface.

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