Abstract: Process for producing a layered ceramic product which includes sintering layers of sinterable particulate ceramic material while in face-to-face contact. Before such contact, the surface of at least one of the layers is modified to provide a zone of weakness between the layers. This zone acts to deflect a crack propagating across the layers thereby increasing the work required to break the product. The product may also have improved fracture toughness.

Abstract: A process for the production of a fibre-reinforced ceramic composite by forming a precursor structure comprising a matrix of a composition comprising particulate ceramic material, liquid diluent and organic binder and fibres within the matrix, in which the fibres are formed from a composition comprising particulate ceramic material, liquid diluent and organic binder, and heating the precursor structure in order to evaporate the liquid diluent, decompose the organic binder and sinter the particles of ceramic material in both the matrix and the fibres. Also, a precursor structure as described. The ceramic composite may have a density of 95% or more of the maximum theoretical density.

Abstract: A silicon carbide fibre, which may have a mean crystallite size of greater than 500A, in which the silicon carbide constitutes greater than 90% by weight of the fibre, and in which the fibre is substantially homogeneous across a transverse section of the fibre. The fibre may be produced by a process which comprises forming a fibre from a homogeneous mixture comprising particulate silicon carbide dispersed in a solution of an organic polymeric material in a liquid medium, and heating the fibre at elevated temperature in order to decompose the organic polymeric material and to sinter the particles of silicon carbide.

Abstract: A process for the production of a fibre-reinforced ceramic composite by forming a precursor structure comprising a matrix of a composition comprising particulate ceramic material, liquid diluent and organic binder and fibres within the matrix, in which the fibres are formed from a composition comprising particulate ceramic material, liquid diluent and organic binder, and heating the precursor structure in order to evaporate the liquid diluent, decompose the organic binder and sinter the particles of ceramic material in both the matrix and the fibres. Also, a precursor structure as described. The ceramic composite may have a density of 95% or more of the maximum theoretical density.