| 摘要 |
<p>1402318 Thermal insulation FOSECO INTERNATIONAL Ltd 5 March 1973 [10 March 1972 7 June 1972] 11362/72 and 26655/72 Addition to 1264022 Heading F2X [Also in Division B5] A method of making a shaped refractory heat insulating article, e.g. a gas turbine casing liner having exterior surfaces which are harder and of greater density than the interior comprises forming a green compact from an aqueous slurry of refractory fibres and inorganic binder, drying the compact in a first drying step, impregnating the dried compact with further binder (which may be different from the first binder) and drying the compact in a second drying step; one of the drying steps is "homogeneous" and does not cause migration of the binder, e.g. microwave or dielectric heating, and the other drying step is "non-homogeneous", e.g. hot air drying. The homogeneous drying step is preferably performed first. The strength of the product is further improved by a final heating step at 300-900‹ C. for “-24 hours. Refractory fibres which may be used include aluminosilicate, calcium silicate, asbestos, alumina, silica, zirconia, boron nitride, silicon carbide, steel, Nimonic alloy, or carbon fibres or a mixture of these. The inorganic binder may be colloidal alumina or silica sol., ethyl silicate, sodium silicate, potassium silicate, metallic phosphate or borate or a mixture. In addition, a particulate refractory filler such as alumina, silica, kieselguhr, silicon carbide, silicon nitride, fire clay or calcined rice busks may be used. The proportions used are refractory fibre 25- 60%, binder 40-70%, filler 0-40%.</p> |
