| 摘要 |
<p>1,263,054. Gas bearing. UNITED KING- DOM ATOMIC ENERGY AUTHORITY. 10 Feb., 1969 [10 Feb., 1968], No. 6686/68. Heading F2A. One member of a gas bearing comprises a unitary body of ceramic material part of which is porous, and part is non-porous. For journal bearings, the body is in the form of a cylindrical sleeve with the ends non-porous and the centre portion porous. The body may be made by placing in a die a combination of two ceramic matrices, one of which on sintering produces the non-porous portion of the body, and the other, the porous portion. The porosity of the material may be regulated by incorporating into the ceramic matrix an additive which is removed at a latter stage. The additive may be a volatile binder or a non-volatile carbonaceous material. If a synthetic fibre is used as the additive, the porosity can be controlled directionally. The carbonaceous additives may be removed by heating in an oxidizing atmosphere at 500- 600‹ C., and the body may subsequently be sintered at 1600-1800‹ C. An example describes the production of an alumina sleeve containing 0À25% by wt. magnesia, nylon being used as the additive.</p> |
