The invention relates to a manufacturing method of low cost niobium tube target, that is, by replacing high cost niobium with low cost titanium in the non-sputtering area of niobium tube target, the purpose of cost reduction is achieved. It includes the following steps: the niobium tube billet is melted and cast by vacuum electron beam, and the inner and outer walls of the niobium tube billet are turned clean. Then the molten pure titanium was cast through the esR furnace in vacuum and filled the inner hole of the niobium tube blank to form the niobium titanium composite rod. After cooling, the niobium-titanium composite rod opened a center hole, and then heated and extruded into the required size specifications; After straightening, the inner and outer surface of niobium-titanium composite pipe is machined to obtain the target of niobium-titanium composite pipe. By this process, niobium consumption can be reduced by 25 ~ 40%, so the production cost of niobium tube target can be effectively reduced.
Compared with planar target, seamless niobium tube target has the advantages of high utilization rate of target material and uniform film. Nb2O5 produced by niobium tube target in magnetron sputtering is a kind of electrochromic material with excellent performance. The film has a high refractive index, and can be prepared with SiO2 and other films with different refractive index. Therefore, Nb2O5 film is more and more widely used, and niobium target has more and more demand. In view of the high price of niobium and easy oxidation, it is necessary to develop a production method of niobium tube target with low cost, large size and environmental protection.
To solve the above technical problems, the technical scheme of the invention is as follows: By casting pure titanium with relatively low cost inside the niobium tube billet, the use of high cost niobium is replaced by low-cost titanium in the non-sputtering area (the current price of niobium strip as raw material is 450 yuan per kilogram, and the price of sponge titanium is 40 yuan per kilogram), reducing the amount of niobium, so as to achieve the purpose of cost reduction.
The linear expansion coefficients of niobium and titanium are similar (7.31μm/(m.K) for niobium and 10.2μm/(m.K) for titanium), so the deformation fits well in the extrusion process. Niobium and Titanium diffused to form a transition layer in the process of casting and extrusion at high temperature, and the interfacial bonding force was good. The residual niobium-titanium composite target after magnetron sputtering can be recycled as niobium-titanium alloy.
The pure titanium with purity of 99.5% or more was smelted by electroslag furnace, and the molten pure titanium was cast and filled with the inner hole of niobium tube billet to form niobium-titanium composite rod under the condition of vacuum degree higher than 0.1Pa. Proper feeding during the casting process to ensure that the inner hole is filled with titanium liquid.
