Published on 23 January 2013
Engineering ceramics can be made in a wide range of sizes and shapes. The turbine blades shown here are an example of the complex shapes that can now be achieved with the advanced fabrication methods available to the manufacturer. These blades have been manufactured to the high material and dimensional specifications demanded by the aerospace industry.
The blades illustrated are made from silicon nitride (Si3N4). This ceramic is one of the many high performance ceramic materials available to designers. The material has a number of desirable properties that make it attractive to the aerospace industry:
- low density = 3.2g/cm3 compared with ~8g/cm3 for superalloys
- high hardness - 1800kgf/mm compared with 800kgf/mm for steel
- high strength at high temperature - for some grades of Si3N4 strength decreases only at temperatures in excess of 1200◦C.
These properties make Si3N4 an ideal material for use at high temperatures, in areas where weight is critical and where a high resistance to wear and erosion is required. The joining issues surrounding the location of the ceramic can be addressed using a number of different technologies.
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