In the early days, whether it was a gasoline or diesel engine, the components inside were actually mainly metal materials. However, in order to improve thermal efficiency, the industry has begun to use new high-temperature structural ceramic materials to replace metal components since the 1990s.

The research at that time found that after the replacement, due to the high refractoriness of ceramics, the temperature of the gas entering the turbine could be increased to 1600-1800 ℃, without taking measures such as cooling. And the critical temperature that super alloys can withstand generally does not exceed 1000- 1050°C. The effective coefficient of the final gas turbine engine is increased by 6%-10%; the fuel consumption is reduced by 10%-30%, even without expensive metals or rare metals (such as Co, Ni, W, etc.), and  fuel with low calorific value can be used.

Compared with other structural ceramic materials, silicon nitride has better heat resistance, fracture toughness, and strength due to the formation of needle-like or long-columnar β-type crystal phases during sintering, and can resist thermal shocks even in air. Even if it is heated to more than 1,000 ℃ in the air, it will not break when it is cooled and heated rapidly. Therefore, it is being reused as a high-temperature structural material in the engine field. In 1998, Japan launched a ceramic gas turbine with an output power of 322kW. Most of the materials used are silicon nitride ceramics, and its thermal efficiency is as high as 42.1%, which is more than double that of conventional gas turbines. It can be seen that the addition of silicon nitride has indeed brought new development opportunities for the engine.

In addition, important applications of silicon nitride high-temperature structural parts are aircraft turbine engines. Taking the turbojet engine of an aircraft as an example, the temperature in the combustion zone of the combustion chamber is as high as 1800-2000 °C. After the introduction of airflow cooling, the wall temperature of the combustion chamber is still above 900 °C. To prevent gas erosion, thermal corrosion and heat insulation, it is also necessary to spray a protective layer; while silicon nitride ceramics are heat-resistant and can still have high strength and stiffness at 1400 ° C. In addition, the specific density of silicon nitride ceramics is only 41% of that of steel bearings, which can effectively reduce the weight of aircraft engines and reduce fuel consumption.