A kind of WC cemented carbide film and its preparation method at room temperature by gradient layer technology

Abstract

The invention discloses a WC hard alloy thin film. The WC hard alloy thin film comprises, on a substrate, a W bottom layer, a W-WC gradient layer and a WC top layer in sequence; the W bottom layer isa buffer layer; the W-WC gradient layer is a transition layer of which components gradually change; the WC top layer is a crystalline state WC thin film with an X-ray diffraction peak of (100) and a hexagonal phase structure, and W:C atomic percentage of the WC top layer is 51.8:48.2; and the microhardness of the WC hard alloy thin film is higher than 24 GPa, and the adhesive force to the substrate is higher than 35N. The invention further discloses a preparation method of the WC hard alloy thin film. The preparation method comprises the steps that a W thin film is deposited to be a bottom layer thin film on the substrate as a buffer layer by using a direct current magnetron sputtering method; then a W-WC gradient layer thin film is grown on the W bottom layer thin film at room temperature; and finally, after the W-WC gradient layer thin film is grown, the WC thin film is grown on the W-WC gradient layer thin film at the room temperature, and the WC thin film is a top layer thin film.According to the WC hard alloy thin film and the preparation method thereof, a W-WC gradient layer technology is adopted, and a W buffer layer technology and a plasma enhancement technology are combined, so that the quality of the WC thin film grown at the room temperature is effectively improved.

Description

technical field [0001] The invention belongs to the technical field of hard alloy thin films, and in particular relates to a crystalline WC hard alloy thin film and a preparation method thereof. Background technique [0002] Tungsten carbide (WC) is a typical cemented carbide material with a simple hexagonal structure. Hexagonal WC is stable until the temperature of 3049K. WC has very excellent physical and chemical properties, such as high hardness, high wear resistance, good thermal and chemical stability, good oxidation resistance, low thermal expansion coefficient, high elastic modulus, and has a certain degree of plasticity, and WC is Most binder phases wet out better than other carbides and are tougher than other carbides. In addition, WC also has high thermal conductivity and high electrical conductivity, which is beneficial for cutting applications. In view of the above advantages, WC, as a hard wear-resistant coating, is widely used in military and civil industrie...

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Problems solved by technology

In 2003, Palmquist et al [J. P. Palmquist, Z. Czigany, L. Hultman, and U. Jansson, Epitaxy growth of tungsten carbide films using C60 as carbon precursor, J. Crystal Growth 259, 12-17 (2003)] took C60 as the Evaporation of carbon source, sputtering with pure W target, and direct sputtering growth of nano-WC film at a relatively low temperature of 400 °C, crystalline substances can be obtained without subsequent heat treatment, and breakthroughs have been made in low-temperature growth, but no follow-up report

Using this method, the temperature required for WC crystallization is still higher than 800°C. Although the annealing process is shorter than the growth process (about a few minutes), the damage to the substrate may not be obvious, but for small and thin parts, The feasibility of this process is still not up to the requirements

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