Preparation and application of fine-grained wear-resistant alumina ceramics

Alumina ceramics has excellent mechanical properties, electrical properties, chemical stability, and has a wide range of raw materials and low manufacturing costs. It is the basic material used to manufacture a variety of high-performance ceramic parts. It is widely used in machinery, electronics, medicine, food, Petroleum, chemical, aviation, aerospace and other fields.

However, alumina ceramics also have the shortcomings of ceramics' high brittleness, poor thermal shock resistance and low fracture toughness. According to Evans’ research results, these factors will greatly affect the wear rate of ceramic materials, especially Hardness and fracture toughness. At the same time, these shortcomings also increase the difficulty of alumina ceramic machining and limit its application in many fields. However, the above problems are not impossible to solve-it is reported that fine-grained nano-ceramics can often show great ductility at low temperatures, so "refining" is a feasible way to complement the shortcomings of alumina ceramics.

Studies have shown that alumina ceramic grain refinement can improve performance, reduce the internal stress of grain boundary materials, not easily cause transcrystalline fracture, improve the density, mechanical properties and chemical properties of the material, and significantly reduce the firing temperature to achieve energy saving purposes—— For example, in the cutting process of alumina ceramic tools, fine-grained materials can effectively delay the crack growth rate, delay the occurrence of grain shedding, and significantly improve the wear resistance and service life of the tool. But we must also know that continuous grain refinement is more difficult for alumina ceramics: firstly, nano-level fine α-Al2O3 is easy to agglomerate and is not easy to disperse; secondly, fine materials have higher surface activity, which is easy to disperse during the sintering process. A chemical reaction causes abnormal growth of crystal grains.