Key factors influencing wear-resisting ceramics using effect

1, the influence of raw material powder

Wear-resisting ceramics is the most important raw materials of high purity Al2O3 powder, its performance is good or bad, and how much content has a great influence on the alumina ceramics.It is inevitable that the absorbing impurities during the preparation of ceramic powder in, the organic impurities will be burned in sintering process, in the process of densification form irregular holes;While inorganic impurities may react with ceramic powder in high temperature stage or residual micro cracks formed in the substrate.Defects caused by impurities on the microstructure of alumina ceramics has distinct effect on the densification, so the preparation of high purity Al2O3 powder is important prerequisite for good performance of alumina ceramics.

Go through multi-channel process of a typical wear-resistant ceramic production in purification of industrial sintering alumina powder as raw material, according to the requirements of the products, according to certain formula mix powder, and then after sintering molding technology were made.Made of wear-resistant ceramic has very good performance, but because of the whole process longer, so the production cost is higher.

In order to save costs, the market also has a direct use minerals such as kaolin) as the main raw material, add a small amount of sintering alumina.Even some use recycles alumina ceramic waste as main ingredients, which has formed the alpha alumina ceramics with the surrounding molecules to form organic combination, density and wear resistance.This is why wear-resisting ceramics spreads on the market one of the main reasons.

2, the influence of raw material powder fineness

Raw material powder fineness is a great influence on product performance, only thin enough raw materials, the final burnt products is likely to form crystallite structure, make it have good wear resistance.Al2O3 powder particles, the more fine, the greater the activity and can promote the sintering, ceramic made of the higher intensity.Small particles can also be scattered because of corundum and different linear expansion coefficient of glass phase in the grain boundary caused by stress concentration, reduce the risk of cracking;Fine grain can also hinder the development of micro cracks, not easy to cause transgranular fracture, is beneficial to improve the fracture toughness, also can improve the wear resistance.

3, the influence of the molding method

Practical production and a large number of studies have suggested that the low porosity, high density of alumina ceramic structure excellent performance.High density means the ceramic grain in the body is arranged closely, when under outside load or corrosive substances erosion is not easy to form damaging the breakthrough.And to get a high density of ceramic body, forming method is the key.Of the alumina ceramic forming general use dry pressing, such as static pressure and hot die casting, and other methods.Different methods have different characteristics, the influence of the performance and microstructure of alumina ceramics sintering will also be different.More generally for complex shape product with grouting or hot die casting technology is given priority to, to a simple products can use dry pressing molding shape.In general, the density of dry pressing molding products are better than hot die-casting molding products.

4, the influence of sintering

For ceramic sintering, simply put is green densification process at high temperature.As temperatures rise and the extension of time, the adhesive failure between powder particles, the strength of the sintered body increases, the powder particles aggregate into hard with some kind of microscopic structure of polycrystalline sintered body, and obtain the required mechanical and physical properties of products or materials.Samples of densification rate and final structure also often reflects its experienced what kind of heat treatment process.

Sintering is a key stage, preparation of ceramic sintering atmosphere had a great influence on the preparation of ceramic materials.High sintering temperature or longer holding time will promote the crystal growth, make fine raw material under high temperature was bred bulky grain, liquid volume increases, such not only strength, abrasion resistance also will weaken the bond.Temperature is too low, of course, easy to cause the sintered body is not tight, wear resistance is not good.USES the advanced electric kiln sintering can be precisely controlled sintering process of cooling and heating, heat preservation, has important effect to improve the performance of wear resistant ceramic, but electric kiln sintering cost and the consumption of refractory material is higher than gas kilns and mines.