Manufacturing process technology of silicon nitride precision ceramics

Silicon nitride is a ceramic material with excellent properties, featuring high hardness, high strength, high toughness, corrosion resistance, high-temperature resistance and high insulation. It is widely used in fields such as electronics, machinery and chemical engineering. This article aims to introduce the advanced ceramic production and processing technology of silicon nitride precision ceramics.

I. Raw Material Preparation

The manufacturing process of silicon nitride precision ceramics mainly consists of steps such as the preparation, mixing, molding, sintering and processing of silicon nitride powder. Silicon nitride powder is an important raw material for preparing silicon nitride precision ceramics. High-purity silicon dioxide and silicon carbide are usually used as raw materials and react at high temperatures to obtain silicon nitride powder. The shape, particle size, preparation method and added impurities of the powder and other factors will affect the performance of ceramics. Therefore, when preparing silicon nitride powder, it is necessary to precisely control the quality of raw materials and the preparation process.

Ii. Mixing

Mixing the prepared silicon nitride powder evenly with additives is one of the key steps in the manufacturing of precision ceramics in industrial ceramic processing. Additives are usually sintering AIDS, which can enhance the density and hardness of silicon nitride during sintering. The mixing process requires precise control of the rotational speed and time of the mixing instrument to ensure uniform mixing results.

Iii. Forming

Forming is an important step in the manufacturing of silicon nitride precision ceramics, which is the process of pressing the mixed silicon nitride powder into the desired shape. It is usually formed by injection molding or dry pressing. During the injection molding process, a certain amount of fine powder and a mixed liquid of additives need to be injected, and the ceramic products are formed through the extrusion of the mold. During the dry pressing process, the well-mixed silicon nitride powder needs to be placed in the mold, and then high pressure is applied to form it into the desired shape. During the molding process, environmental factors such as temperature and humidity need to be strictly controlled to prevent the caking and accumulation of silicon nitride powder.

Iv. Sintering

Sintering is a key process in the manufacturing of silicon nitride precision ceramics, which can endow ceramic products with a dense structure and excellent mechanical properties. Vacuum sintering or nitrogen sintering methods are usually adopted. During the vacuum sintering process, silicon nitride powder is sintered into dense ceramic products under high temperature and pressure. During the nitrogen sintering process, using nitrogen to protect sintering can prevent problems such as oxidation and volatilization. During sintering, it is necessary to control the sintering temperature and time to ensure the compactness and mechanical properties of the finished product.

V. Processing

Advanced ceramic production and processing is the processing procedure of silicon nitride precision ceramic products, including steps such as grinding, polishing and processing. The surface quality and precision of ceramic products can be improved through processing. When processing, it is necessary to select appropriate processing equipment and technological methods, and precisely control processing parameters to obtain high-quality silicon nitride precision ceramic products.

In conclusion, the manufacturing technology of silicon nitride precision ceramics requires the mastery of multiple key technologies, including powder preparation, mixing, molding, sintering and processing, etc. The quality and precision of these technologies directly affect the quality and performance of the finished products. With the continuous advancement of technology, the manufacturing technology of silicon nitride precision ceramics will gradually improve, which is expected to bring more development opportunities to various industries.