What are the methods for sintering silicon nitride ceramics?

Silicon nitride ceramic is a type of inorganic material ceramic that has high strength and cannot undergo shrinkage deformation during sintering. It is a relatively hard substance with high temperature resistance and low density characteristics, and is widely used. There are many preparation methods for silicon nitride ceramic, and Kezhong Ceramic Factory will introduce them in detail below.

1. Hot press sintering method. It is a method of sintering using Si3N4 powder and a small amount of other additives at a certain temperature and pressure. This method has been widely used internationally, such as in the United States and the United Kingdom for preparing silicon nitride ceramics. The mechanical properties of the ceramics produced by this method are very good, with high density and strength, which can significantly improve the oxidation resistance of the ceramics. However, the sintering equipment used is relatively complex, and the production cost is also relatively high. There are certain limitations in the accuracy and size of the products produced, usually only some products with relatively simple shapes can be produced, and mechanical processing also has certain difficulties.

2. Reaction sintering method. It is first made by sintering the silicon powder raw material into a specialized equipment. The silicon nitride ceramic produced by this method has very small shrinkage performance and can obtain products with minimal size changes. Moreover, the product can be directly used without the need for grinding. This method can produce products with complex shapes, structures, and relatively precision, and the cost is also relatively low. Therefore, it is widely used, but the only drawback is that the nitriding time is somewhat long.

3. Normal pressure sintering method. It is sintered under normal pressure within a certain temperature range, followed by air pressure sintering. This method can improve the density of silicon nitride ceramics and enhance their strength.

In addition to the above three methods, there are also pressure sintering methods for the preparation of silicon nitride ceramics. The silicon nitride ceramics produced by this method have strong wear resistance and high toughness, making it more suitable for large-scale production. It can be seen that all four methods have their own advantages and disadvantages, and everyone can choose the appropriate preparation method according to their actual needs.

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