The high uniformity vanadium titanium base hydrogen storage alloy and its preparation method include the following steps: 1. Weigh raw materials according to the composition ratio; 2. 2. Add the raw materials with high melting point into the water-cooled copper crucible of vacuum induction suspended melting furnace, and add the raw materials with low melting point into the feeder of vacuum induction suspended melting furnace; 3. After the high melting point raw materials are completely melted, add the low melting point raw materials; 4. At the end of smelting, alloy ingot is obtained with furnace cooling, and the alloy ingot is turned over and smelted again; 5. Vanadium titanium base hydrogen storage alloy ingot is obtained by casting mold after completion. By adopting and improving the vacuum induction suspension melting technology, the invention can not only avoid serious alloy burning loss, crucible corrosion and other problems, but also has the function of alloy purification in the preparation process, which effectively inhibits the macroscopic segregation on the composition. The hydrogen storage alloy prepared is 3-5MPa, and the reversible hydrogen storage capacity can reach 3.1wt % when hydrogen is absorbed at 0℃ and discharged at 60℃. Obvious technological advantages.
Vanad-based titanium hydrogen storage alloy has the advantages of large hydrogen storage capacity at room temperature and fast hydrogen absorption and release speed. It has been applied in the fields of hydrogen storage, purification, compression and hydrogen isotope separation, and has a broad application prospect in the fields of fuel cell vehicle, heat energy storage and transportation, heat energy and mechanical energy conversion. At present, vanadium titanium base hydrogen storage alloy is usually prepared by melting method, but the main raw materials of vanadium titanium base hydrogen storage alloy, iron vanadium intermediate alloy, metal Cr, sponge Ti melting point is as high as 1800℃, 1857℃, 1668℃, the melting point of the alloy is also as high as 1600℃. What is more serious is that vanadium and titanium have high activity at high temperature. During melting, it is easy to react with the main components of alumina, magnesium oxide and zirconia crucible, resulting in alloy contamination and crucible damage.
In order to solve the problem of Ti reacting with the main component of common crucible at high temperature, a "vacuum induction melting method for hydrogen storage alloy containing titanium" was developed, and hydrogen storage alloy TiFe series was prepared by using crucible with high stability CaO and modified calcium oxide refractory material. But the melting point of TiFe hydrogen storage alloy is only about 1300℃, while that of vanadium-titanium hydrogen storage alloy is about 1600℃. The highest use temperature of CaO crucible on the market is 1600℃, and the highest use of 1500℃ is about 20 times. Obviously, the melting point of vanadium-titanium hydrogen storage alloy is very close to or has exceeded the maximum operating temperature of the CaO crucible, using the CaO crucible to melt the alloy will still lead to the reaction of the alloy with the crucible or the crucible cracking.
