What are the manufacturing processes of silicon nitride ceramic rings ?

Processing flow and methods: Ultrasonic (vibration waves with a vibration frequency exceeding 16,000 times per second) processing is the use of tools (molds) that generate ultrasonic vibrations to drive the abrasive between the tools and ceramic components. Suspension, impact and polishing components are processed. As the tool is fed in three dimensions, the shape of the tool end is gradually replicated. On ceramic components, commonly used abrasives are boron carbide, silicon carbide and aluminum oxide. The liquid is water. In order to improve the processing quality of the material surface, kerosene or machine oil can also be used as the liquid medium. Due to the small force on the components during the processing, the material surface produces small mechanical stress, and the damage to the material is small and the surface is rough. Ultrasonic processing with good precision is suitable for processing various hard and brittle materials with complex shape requirements and non-conductivity.

The purpose of ceramic sintering is
hot press sintering (HPS), which is to hot press sinter Si3N4 powder and a small amount of additives (such as MgO, Al2O3, MgF2, Fe2O3, etc.) at a pressure above 1916MPa and a temperature above 1600 The hot-pressed sintered Si3N4 ceramics adopted by the company have a strength as high as 981MPa. Additives and phase composition have a great influence on product performance during sintering. Due to strict control of the composition of grain boundary phases and proper heat treatment after sintering of Si3N4 ceramics, Therefore, even if the temperature is as high as 1300, the strength (up to 490MPa or more) of the Si3N4 series ceramic material will not be significantly reduced, and the creep resistance can be improved by three orders of magnitude. If the Si3N4 ceramic material is pre-oxidized at a high temperature of 1400-1500 Si2N2O phase is formed on the surface of the ceramic material, which can significantly improve the oxidation resistance and high temperature strength of Si3N4 ceramics. The manufacturing cost is high and the sintering equipment is complicated. Due to the large shrinkage of the sintered body, the dimensional accuracy of the product is limited to a certain extent. It is difficult to manufacture complex parts. Only parts with simple shapes can be manufactured, and the machining of the workpiece is also difficult.

Silicon nitride application fields
Utilizethe characteristics of light weight and high rigidity of silicon nitride ceramics, which can be used to manufacture ball bearings. It has higher precision than metal bearings, generates less heat, and can withstand higher temperatures and corrosive media . The steam nozzle made of Si3N4 ceramics for operation has the characteristics of wear resistance and heat resistance, and there is no obvious damage after being used in a 650°C boiler for several months, while other heat-resistant and corrosion-resistant alloy steel nozzles can only be used 1-2 under the same conditions moon.