Abstract: A cermet material comprises an intergrown network of a minor proportion of ceramic such as TiB.sub.2 in a metal matrix such as Al. The cermet is prepared by forming a minor proportion by weight of a ceramic phase in situ in a molten metal phase and holding the mixture of elevated temperature for a time to effect formation of an intergrown ceramic network.

Abstract: A shaped refractory article of titanium diboride or other metal has a microstructure with a weight average grain diameter of from 0.5 to 5 microns and substantially no grains larger than 10 microns diameter, from 10% to 45% by volume being made up of interconnected pores the majority having a diameter not substantially greater than 5 microns, porosity and grain size being substantially uniform throughout the microstructure, the article containing not more than about 0.2% by weight of oxygen and not more than about 0.5% by weight of carbon. The article may include inert particulate material in a matrix of the porous metal boride.The article may be formed by forming a uniformly mixed body of reactants into shaped compacts and heating the compacts to cause evolution of carbon monoxide and formation of a coherent reaction sintered product. Numerous reaction schemes are given, but the following are preferred:2TiO.sub.2 +B.sub.4 C+3C.fwdarw.2TiB.sub.2 +4CO (1)TiO.sub.2 +B.sub.2 O.sub.3 +5C.fwdarw.TiB.sub.