Silicon nitride ceramic is an inorganic material ceramic that does not shrink during sintering. Silicon nitride is very strong, especially hot-pressed silicon nitride, which is one of the hardest materials in the world. It has the properties of high strength, low density and high temperature resistance.
The mechanical structure of the future aeroengine will be simpler than the existing type, with fewer parts, and operating at a higher turbine inlet temperature and component load, and its reliability and component life will also be improved. Turbine materials must meet the requirements in terms of tensile strength, creep resistance, high temperature corrosion resistance and impact damage resistance. The use of ceramic materials with better thermal performance can reduce the amount of cooling air required and significantly increase the gas temperature.
In the past, large aircraft engines mainly used nickel-based heat-resistant materials, and silicon nitride materials have higher strength, better creep strength and oxidation resistance than nickel-based heat-resistant alloys at temperatures above 1000°C, and have a small specific gravity. It is only 40% of the heat-resistant alloy, which can meet the requirements of future aviation engines to reduce weight and reduce fuel consumption.
Silicon nitride ceramics can be used as turbine blades, mechanical seal rings, high-temperature bearings, high-speed cutting tools, permanent molds, etc. in the machinery industry. Many devices in the traditional machinery industry use metal materials. Since the metal will be corroded, the reliability and service life of these devices are greatly affected. Silicon nitride ceramic materials have excellent wear resistance, corrosion resistance, and high temperature thermal shock resistance. , It can replace metal materials and be used in the field of machinery industry.
For example, silicon nitride can be used to manufacture ball bearings due to its light weight and high rigidity. It has higher precision than metal bearings, generates less heat, and can operate in higher temperatures and corrosive media. The steam nozzle made of silicon nitride ceramics has the characteristics of wear resistance and heat resistance, and no obvious damage after being used in a 650℃ boiler for a few months, while other heat and corrosion resistant alloy steel nozzles can only be used under the same conditions. Months.
Silicon nitride ceramics are covalent compounds, and their bonding mainly relies on covalent bonds between atoms. The prepared material itself has high hardness and wear resistance. Silicon nitride has high hardness, second only to a few superhard materials such as diamond and cubic boron nitride, and has low friction coefficient and self-lubricating properties. In the ultra-fine powder and food processing industries, the performance of silicon nitride ceramic grinding balls is higher than that of traditional grinding balls, with higher hardness and superior wear resistance.
With the rapid development of information technology, the integration level of integrated circuits is getting higher and higher, and the wiring density is getting higher and higher. If the electronic packaging substrate cannot dissipate heat in time, a large amount of heat will accumulate on the integrated circuit, which will eventually lead to its failure and damage. Therefore, the thermal conductivity of the substrate is extremely important. Silicon nitride ceramics are structural ceramic materials with the best overall performance. The theoretical thermal conductivity of single crystal silicon nitride can reach more than 400W·m-1, and it has the potential to become a high thermal conductivity substrate. In addition, its excellent mechanical properties and good high thermal conductivity potential make silicon nitride ceramics expected to make up for the existing The lack of substrate materials such as alumina and aluminum nitride has great market prospects in the application of electronic packaging substrates.
Silicon nitride ceramic materials have excellent chemical stability and excellent mechanical properties, and can be used as parts on thermal equipment such as crucibles, burners, aluminum electrolytic cell linings, etc. in the metallurgical industry. Silicon nitride ceramics have good oxidation resistance. The oxidation resistance temperature can be as high as 1400°C. It is stable in a dry oxidizing atmosphere below 1400°C, and the use temperature can reach 1300°C. And silicon nitride material can be used in the environment of rapid cold and rapid heat, so it also has a very wide range of applications in the metallurgical industry.