How to achieve surface smoothness of alumina ceramics?

In order to improve the accuracy of the product, most alumina ceramic materials require further precision processing after sintering to achieve higher surface smoothness. However, alumina ceramics are not ordinary materials after all. How can we do better?
Due to the high hardness of alumina ceramic materials, it is necessary to use harder grinding materials such as silicon carbide, B4C, or diamond for polishing. In addition, the lubricity of the surface of alumina ceramic materials should be improved in advance during polishing.
In the precision machining of alumina ceramic materials, the commonly used method is to gradually polish from coarse to fine, and then polish the surface. When polishing, Al203 micro powder or diamond slurry smaller than 1 μ m can be used for grinding and polishing. Of course, laser processing and ultrasonic processing can also achieve the purpose of polishing and grinding alumina ceramics. The above-mentioned precision processing can improve the surface smoothness of alumina ceramic materials, and then the mechanical strength of alumina ceramics can be improved through processing, which is known as alumina ceramic strengthening technology. In fact, advanced technologies such as electron beam vacuum coating, sputtering vacuum coating, or chemical vapor deposition are used to toughen the surface of alumina ceramics.
Through these methods, a layer of silicon compound film can be deposited on the surface of alumina ceramics, and alumina ceramics can be toughened by heating at 1200-1580 ℃ Practice has proven that enhanced alumina ceramics can significantly improve mechanical strength and obtain ultra-high strength alumina ceramics on the original basis.