Due to its advantages of high melting point, high ductility, high chemical stability, low thermal conductivity and good electrical conductivity, the refractory metal tantalum has become the preferred coating material for high temperature resistance, wear resistance and reinforced corrosion, and has been widely used in aerospace, weapons, chemical engineering, electronics and communication fields. However, due to high internal stress, poor adhesion of coating/substrate, and brittleness, the application scope of tantalum coating in harsh service conditions is limited. Preparation methods of tantalum coating at present basically has the following two kinds: one is the magnetron sputtering method, this method has low deposition temperature, as well as good surface quality, is a commonly used method of preparation of metal tantalum coating, but deposition rate is low (only 1 ~ 1.5 um um/h/h), preparation of tantalum film is mainly composed of beta metastable phase, brittleness is big, easy cracking and peeling. The second method is chemical vapor deposition, which mainly USES the halide of tantalum (such as tantalum pentachloride Cl5) as the gas source through heating and evaporation, and USES hydrogen to reduce the tantalum coating at a certain temperature. On the deposition rate is magnetron sputtering method, but the method is of high deposition temperature (900 ℃ ~ 1100 ℃), the residual thermal stress is big, coating the surface crack of yi, in addition, this method is a pioneer air cannot achieve stable input, deposition rate and coating thickness can't stability control and source reduction after generated hydrogen halide product such as to the serious environmental pollution, high demands on deposition equipment. Because of its high deposition rate, strong film/substrate adhesion and uniform coating thickness, arc ion plating has become the main research method for preparing metal and its nitride/carbide coatings. However, the current arc ion plating technology is mainly used for depositing single or multiple layers (Ti,Al) N, TiN, ZrN and other hard films, decorative films and functional films. The maximum current of the arc source equipped with the ion plating equipment is usually lower than 120A. Due to the low arc source current, the arc ion plating technology of refractory metal coating has not been studied.
The invention relates to a preparation method of metal tantalum coating, which is characterized in that: a high-purity tantalum target is selected as the target material and placed in a vacuum chamber, through high-purity argon, and the air pressure is maintained at 3× 10-1pa ~ 6× 10-1pa. Start the arc source, start the pulse bias power supply, adjust the negative bias of the pulse to 200V ~ 350V, duty cycle is 70% ~ 90%; The tantalum coating of the workpiece is deposited by the ignition arc for 30min ~ 60min, wherein the target material of high purity tantalum is tantalum ingots smelted and forged by electron beam, with a purity of over 99.95%, and the maximum current of the arc source is 300 ~ 600A.
