Abstract: A method for the manufacture of salt cores is described. The cores are used for the production of cavities in articles which have been made by a pressure casting technique. The cores are resistant to impregnation and fracture during, for example, the application of pressure during squeeze casting. In particular, the method comprises mixing coarse and fine particle salt powders in the ratio from 50/50 to 70/30 coarse/fine, the coarse powder having a maximum particle size of 250 micrometers, the fine powder having a maximum particle size of 25 micrometers. A lubricant, for example, oleic acid is added, possibly the quantity thereof being in the range 0. 1 to 1.0 wt %. A surfactant, such as a silane, also may be added, possibly the quantity thereof being in the range 0.1 to 1.0 wt %. The mixture is pressed to form a core having a density of at least 1.90 g/cm.sup.3 ; and is sintered at a temperature between 650.degree. C. and 775.degree. C., for a time in the range 15 minutes to 1 hour.

Abstract: A method is described for the production of a porous ceramic body and the subsequent infiltration of the body with a molten metal to produce an article having a reinforced metallic matrix. The article may be further worked by known techniques such as extrusion or forging, for example.