Polycrystalline WC film high in stoichiometric ratio and low temperature preparation method thereof

Abstract

The invention discloses a polycrystalline WC film high in stoichiometric ratio and a low temperature preparation method thereof. The X-ray diffraction strongest peak of the polycrystalline WC film isa (100) diffraction peak, and the polycrystalline WC film has a hexagonal phase structure; the atomic percentage of W: C in the WC film is 49.7: 50.3-50.5: 49.5, and a high stoichiometric ratio is achieved; and the microhardness of the WC film is higher than 23 GPa, and the adhesive force with a substrate is higher than 31 N. A direct-current magnetron sputtering method is adopted for the low temperature preparation method of the polycrystalline WC film, a dual-target co-sputtering method of a high-purity W metal target material and a graphite target material is adopted, Ar-CH4 mixed gas is work gas, the Ar: CH4 partial pressure ratio is 1: 1, and the gas pressure intensity is 1.5 Pa; and the WC film grows in a Ar-CH4 plasma atmosphere, and the growing temperature is 300-500 DEG C. According to the dual-target co-sputtering method, the C loss is effectively supplemented, the crystal quality of the low temperature growing WC film is improved, the made WC film is made to be a crystal state film, and the high stoichiometric ratio is achieved.

Description

technical field [0001] The invention belongs to the technical field of carbide thin films, in particular to a polycrystalline WC thin film and a low-temperature 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 industries such...

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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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