Tungsten is a metal with a high melting point, high density and high hardness with a body-centered cubic structure. The alloys with tungsten as the matrix and added with other elements are called high specific gravity alloys. How to prepare heavy tungsten carbide (in terms of mass percentage, alloy composition: tungsten (W) 98.0%, zirconium oxide (ZrO2) 2.0%, and unavoidable impurities)?
Picture of Preparation Method of heavy tungsten carbide
The specific steps of the preparation method of heavy tungsten carbide are as follows:
1) Preparation of composite tungsten powder
Dissolve 134.33kg of ammonium metatungstate and 6.97kg of zirconium nitrate in water respectively, and then mix the two solutions uniformly to obtain a mixed solution; take the mixed solution and evaporate to dryness, and the obtained dry powder is calcined at 450°C for 5 hours; put the calcined product into The reduction in the push rod reduction furnace is divided into two stages. The temperature of the first stage of reduction is 550℃, the reduction time is 1.5 hours, and the temperature of the second stage of reduction is 900℃, and the reduction time is 4 hours. powder.
2) Ball milling and press forming
Put the composite tungsten powder into a stirred high-energy ball mill, and pass in high-purity argon gas (purity greater than 99.99%). The ball mill material is GCrl5 balls with a diameter of 6mm. The ball-to-battery ratio (mass ratio) is 10:1. The speed of the ball mill is controlled as 120 revolutions per minute, ball milling time is 12 hours, and modified composite tungsten powder is obtained. The modified composite tungsten powder was put into a rubber sleeve with a wall thickness of 2 mm, and then placed in a 300 MPa ultra-high pressure chamber for cold isostatic pressing, and the pressure holding time was 60 minutes to obtain a cold pressed blank.
Picture of Preparation Method of heavy tungsten carbide
3) Sintering
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