Alumina ceramic balls are currently commonly used high-tech ceramic products. They have attracted attention for their excellent wear resistance, corrosion resistance, high mechanical strength, and high grinding efficiency. Alumina ceramic balls are mainly used in the preparation of blank glaze in the ceramic industry and the production of fine powder in the electronics, chemical, metallurgical, coal and other industries.
Alumina itself is an excellent material. Compared with other grinding media, it has high hardness and high specific gravity. The load of materials to be ground in the same grinding body is increased, the balls are dense, the specifications are neat, and the collision probability of the ball and the material is increased. , Can greatly shorten the grinding time and improve the grinding efficiency. From this point of view, wear resistance is an important indicator to measure the quality of alumina ceramic balls. So what are the factors that affect the wear resistance of alumina ceramic balls?
We analyze from several factors such as raw materials, auxiliary raw materials, forming and firing.
raw material:
α-Al2O3: As the basis of the product, alumina powder, the main raw material of alumina, is the most important thing. Its purity, α-Al2O3 conversion rate, and powder fineness all affect the wear resistance of alumina ceramic balls An important factor in sex. As the alumina ceramic ball with the main crystal image of α-Al2O3, it is extremely important to choose a powder with good sintering activity and suitable α-Al2O3 conversion rate. The conversion rate has a great influence on the quality of the alumina ceramic ball. α-Al2O3 has a high conversion rate, its calcination temperature is relatively high, the hardness of the material increases the difficulty of powder grinding, and the sintering activity is small. If the sintering temperature is increased, the cost will not only increase, but also crystal grains will grow, which is not conducive to A uniform microstructure is formed, but wear resistance decreases. If the conversion rate of α-Al2O3 is low, its calcination temperature is relatively low, the powder hardness is weakened, the grinding is relatively easy, and the sintering activity is large. However, the product shrinks more as the crystal form changes, resulting in cracking and deformation of the product.
Granularity of 95 alumina ceramic powder:
under the same conditions, the finer the powder, the larger the specific surface area, the higher the surface free energy, the greater the driving force for sintering, and the lower the sintering temperature. Strictly controlling the fineness of α-Al2O3 powder and other powders in production is one of the keys to grasp the overall quality of alumina ceramic balls.
Auxiliary raw materials:
The appropriate type and quantity of auxiliary raw materials should be selected, the chemical composition should be stable, and the particle size should be uniform. This will not only reduce the sintering temperature, but also increase the density and wear resistance of the alumina ceramic ball.
Auxiliary raw materials:
The appropriate type and quantity of auxiliary raw materials should be selected, the chemical composition should be stable, and the particle size should be uniform. This will not only reduce the sintering temperature, but also increase the density and wear resistance of the alumina ceramic ball.
The formula of the Al2O3-SiO2-CaO-MgO quaternary system has been adopted by many manufacturers, but the production conditions and process formulas are different, but the basic theory tends to be the same. Adding a proper amount of MgO can form magnesia-aluminum spinel with alumina, which can inhibit the growth rate of crystals in high-alumina porcelain, make the crystals finer, and improve the performance of the product. MgO can also form low-melting glass with alumina and other substances. Reduce the sintering temperature and play the role of fluxing. CaO makes the firing process easy to control, and the performance of the porcelain body is stable.
Forming:
The application of advanced isostatic pressing technology can avoid the shortcomings of hollow delamination and poor compactness, not only can improve the yield and production efficiency, but also have a very obvious effect on improving the wear resistance.
Sintering:
Sintering is the pipe fitting that determines product quality, so formulating a reasonable temperature rise curve is a key factor to ensure product quality. Properly increasing the temperature and extending the holding time is beneficial to the product, which can make the reaction sufficient, and the pores will be slowly eliminated, thereby obtaining high-quality products.
To sum up, the production process of alumina ceramic grinidng balls is a very complex system engineering. Various parameters are related to each other and influence each other. The experience should be constantly summarized in the production to form a set of reasonable process parameters. Produce high-quality alumina ceramic balls.
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