Fabricating of Dense Silicon Nitride Parts by Hot Isostatic Pressing

Concerning the fabrication of advanced components of dense silicon nitride, many methods of approach have been reported on in literature. To date, none of these attempts for the fabrication of turbine rotors has been considered feasible.

The HIP process, it is believed, can offer an economically viable solution for fabrication of advanced ceramic components when the following reasons are considered:

1. a)
   hot isostatic pressing is a well established technique.
2. b)
   dense silicon nitride can be produced without any additives.
3. c)
   fully isotropic dense silicon nitride is achieved.
4. d)
   no reaction with capsule material.
5. e)
   high M.O.R. values at high temperatures.
6. f)
   consistently high Weibull m-module.
7. g)
   very high creep resistance.

The HIP process implies that even monolithic turbine rotors can be fabricated to final shape.

The principle of the HIP process allows production of a large number of components simultaneously, thus offering possibilities for economic production on a large scale.