This invention relates to a new ceramic-metal composite body and a method for producing the same. Particularly, a compliant layer composition is utilized for preventing the rupture of a ceramic article and/or the yielding or failure of a metal during the pouring, solidification and cooling of a molten metal which has been cast around the ceramic. A slurry composition for the compliant layer includes plaster of paris, a liquid vehicle and a filler material. The slurry composition is coated on the ceramic article and thereafter is heat-treated to form a compliant layer. Ceramic-metal composite bodies comprising low strength hollow articles and high expansion coefficient metals may be manufactured according to the method of this invention.
The insulation barrier is formed of a body of expanded polystyrene which is impregnated with sodium silicate. In addition, a coating formed of a metallic-based inorganic material is applied over at least one surface of the body. The sodium silicate is applied in solution form and maintained within the body by a wetting agent in the solution. The coating is be applied by a coating roller either before or after drying of the impregnated polystyrene body.
A cast iron exhaust manifold having an inside surface covered with a ceramic coating comprising, by weight, about 30% to about 70% unfused silica, about 5% to about 30% magnesia, about 5% to about 20% alumina and about 3% to about 10% sodium oxide. The coating will preferably be built up in multiple layers at least one of which is relatively porous and another is relatively dense resulting from vacuum degassing of the slurry used to deposit the coating.
A process is presented for the fabrication of a metal/ceramic composite by a non-vapor phase oxidation of a molten metal by contacting said molten metal at an elevated temperature with a sacrificial ceramic preform. The shape of the preform is retained but the ceramic preform is reduced, oxidizing the molten metal. A preferred sacrificial ceramic preform is silica, but can also be, for example, mullite, titania or zirconia, and the preferred molten metal is aluminum or an aluminum alloy. Thus, for example, is produced from immersing a silica preform into molten aluminum alloy, an Al/Al.sub.2 O.sub.3 composite metal/ceramic article which does not contain silica or silicon and which is extremely tough.
The invention is directed to a non-vapor phase process for forming a metal/ceramic composite containing a relatively inert metal such as silver, copper, or nickel by the reaction of a reactive metal or metal alloy containing the inert metal, and a sacrificial ceramic preform. The resulting metal/ceramic composite is essentially the same shape and dimensions as the sacrificial ceramic preform, and exhibits improved physical and mechanical properties, including improved corrosion and wear resistance.
A ceramic core for use in casting an article such as for example an airfoil, wherein the ceramic core has a pocket located at or near a region of the core that is otherwise associated with occurrence of a localized casting defect in the cast article. A covering is disposed on the core to cover the pocket and provide core outer surface features.
