This paper describes the preparation method and application of niobium-titanium alloy wire for high-vacuum suction. The process involves uniformly mixing sponge titanium, niobium sheets, and a titanium-niobium master alloy to prepare an alloy ingot. The ingot undergoes homogenization treatment to eliminate compositional segregation. It is then subjected to forging, resulting in a billet diameter of 50-60 mm. The billet is then subjected to high-temperature rolling until a billet diameter of less than 6 mm is obtained. A hot drawing process is then performed until a billet diameter of less than 1 mm is obtained. A cold drawing process is then performed, and when the deformation reaches 40%-50%, intermediate annealing is carried out at a temperature of 600-700℃ until a billet diameter of less than 0.3 mm is obtained. The surface is then pickled to remove oxide scale, followed by ultrasonic cleaning and drying before being coiled into niobium-titanium alloy ultrafine wire. This invention utilizes magnetic levitation melting, high-temperature forging, and cold drawing processes to design and prepare niobium-titanium binary alloy ultrafine wires (diameter ≤0.3 mm). A porous, rough structure is then created on the wire surface using micro-arc oxidation technology. When used as a high-vacuum gas-getting device, it offers advantages in high efficiency and low cost, possessing significant market value.
It is known that some transition metals, such as titanium, zirconium, and hafnium, can form a highly adsorption-capacitant active surface upon activation, exhibiting excellent gas-getting performance and reacting chemically with almost all gases except inert gases. Furthermore, the gas-getting performance of a gas-getting material primarily depends on its surface adsorption capacity, placing higher demands on the alloy's adsorption surface area. Research has found that a larger specific surface area results in a larger effective interaction area between the material and active gas molecules, leading to a higher adsorption probability. Therefore, utilizing transition metals to prepare novel adsorption alloy materials that simultaneously possess high adsorption characteristics, excellent mechanical properties, and a large specific surface area has enormous application potential. Researchers have attempted to prepare titanium alloy wires by adding alloying elements such as Mo, Ta and Nb. These wires have found applications in some high-vacuum devices due to their high gas-getting performance, large specific surface area, and good weldability.
Titanium-tantalum wires, once heated and degassed, possess inherent gas-getting capabilities and can be used as non-evaporative getters. During the activation process, a titanium thin film layer of a certain thickness is pre-formed on the surface of the alloy wire, further enhancing its gas-getting effect. By lowering the substrate temperature during the titanium film formation process and then appropriately increasing the operating temperature for a certain period after film formation, the system's vacuum level can be maximized. However, further research has found that with an appropriate increase in the number of activation cycles, the outgassing of the titanium-tantalum wire gradually decreases, the titanium film thickness increases, and the system's vacuum level gradually rises.
Niobium-titanium alloy wires for high-vacuum gas getters are prepared using one of the aforementioned methods; the composition consists of 40%–60% niobium and the balance titanium.
