Rare Earth Yttrium Regulates Tungsten Zirconium Alloy Process

Tungsten plays an important role in high temperature materials and functional materials. Widely used in the electronics and light source industry, in the aerospace, foundry, weapons and other departments for the production of rocket nozzles, die-casting molds, armour-piercing core, contacts, heaters and heat shields.

With the development of science and technology, the requirement of tungsten alloy properties is getting higher and higher, and ordinary tungsten alloy can not meet the requirement. In order to improve the properties of tungsten zirconium alloy, tungsten alloy need to be strengthened. Zirconia has stable chemical properties, high melting point, boiling point, high hardness, good conductivity at high temperature, good thermal stability and low creep at high temperature. ZrO₂ is used to strengthen tungsten alloy to improve its properties.

In the sintering process, the doped rare earth yttrium inhibits the deformation of the alloy through the action of yttrium, and obtains high-performance tungsten alloy materials. The preparation process includes the following steps:

Step 1: Weigh sodium metatungstate and distilled water according to the molar ratio of 2:1, and dissolve sodium metatungstate in distilled water to form sodium metatungstate aqueous solution for reserve.

Step 2: Zirconium nitrate, yttrium nitrate and distilled water are separately weighed according to the mass ratio of 9:10:30. Zirconium nitrate and yttrium nitrate are dissolved in distilled water. Then the mixture is stirred for 1-2 hours at 180 rpm to form a mixed solution for reserve.

Step 3. The solution prepared in step 1 is continuously stirred at 300 rpm/min, and the mixed solution prepared in step 2 is continuously added in the stirring process. The volume ratio of the solution in step 2 to the solution in step 1 is 1:10. The prepared solution is heated by adding ethanol until the precipitate appears, and the dried alloy precursor powder is prepared for reserve.

Step 4. The precursor powders prepared in step 3 were calcined for 3-4 hours at 550 ℃, then the calcined powders were reduced in hydrogen atmosphere for 140-180 minutes to obtain W-Zr-Y ternary alloy powders.

The results of high resolution transmission electron microscopy (HRTEM) electron diffraction (EDD) show that yttrium completely enters the tungsten crystal lattice. The alloy has tungsten structure in the range of W=95-99.5wt%, ZrO 2=0.5-5wt%2 and Molzr:MolY=97:12. By comprehensive analysis of scanning electron microscopy, the composition distribution is uniform, the agglomerated particles are about 1 micron, and the size accuracy of tungsten products does not change unfavourably.

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