Abstract: A ceramic cutting insert for high speed machining of materials is provided having an integral chip control surface thereon.

Abstract: A ceramic cutting insert for high speed machining of materials is provided having an integral chip control surface thereon.

Abstract: A ceramic composition is provided having a alumina based matrix with silicon carbide whiskers and titanium carbide phase dispersed therein. The composition includes about 1.0 to less than 30 volume percent silicon carbide whiskers, about 5 to about 40 volume percent titanium carbide phase. The sum of the volume percents of silicon carbide whiskers and titanium carbide phase is less than about 60 volume percent.

Abstract: A metalcutting insert is provided with an alumina based ceramic composition composed of (in volume percent, v/o): about 1.5 to 37.5 silicon carbide whiskers; about 5 to 17.5 zirconia; residue of a magnesium oxide addition added in an amount effective to enhance the metalcutting lifetime of the cutting edge of the insert; and an alumina based matrix in which the silicon carbide whiskers, zirconia and residue of magnesium oxide are substantially homogeneously distributed. At least 2 v/o of the alumina based ceramic composition is tetragonal zirconia.

Abstract: An alumina based ceramic composition is provided containing (in volume percent, v/o): about 1.5 to 17.5 silicon carbide whiskers; about 5 to 17.5 zirconia; residue of a magnesium oxide addition added in an amount of about 0.03 to 3; and an alumina based matrix in which the silicon carbide whiskers, zirconia and residue of magnesium oxide are substantially homogeneously distributed. At least 4 v/o of the alumina based ceramic composition is tetragonal zirconia.

Abstract: An alumina based ceramic composition is provided containing (in volume percent, v/o): about 1.5 to 37.5 whiskers; about 5 to 17.5 zirconia; residue of a magnesium oxide addition added in an amount of about 0.03 to 3 v/o; and an alumina based matrix in which the silicon carbide whiskers, zirconia and residue of magnesium oxide are substantially homogeneously distributed. At least 2 v/o of the alumina based ceramic composition is tetragonal zirconia.

Abstract: A metalcutting insert is provided with an alumina based ceramic composition composed of (in volume percent, v/o): about 1.5 to 17.5 silicon carbide whiskers; about 5 to 17.5 zirconia; residue of a magnesium oxide addition added in an amount effective to enhance the metalcutting lifetime of the cutting edge of the insert; and an alumina based matrix in which the silicon carbide whiskers, zirconia and residue of magnesium oxide are substantially homogeneously distributed. At least 4 v/o of the alumina based ceramic composition is tetragonal zirconia.

Abstract: A metalcutting insert is provided with an alumina based ceramic composition composed of (in volume percent, v/o): about 1.5 to 12.5 silicon carbide whiskers and about 7.5 to 17.5 v/o zirconia. The silicon carbide whiskers and zirconia are substantially homogeneously distributed in an alumina base matrix. Preferably, at least about 7 v/o of the alumina based ceramic composition is tetragonal zirconia.

Abstract: A method of manufacturing a shaped ceramic article by hot isostatic pressing comprising the following steps: (a) forming a compact of sinterable ceramic compositions, (b) applying a coating to the compact by vapor deposition of a ceramic composition that does not become vitreous before or during the subsequent isostatic pressing step, and (c) heating and isostatically pressing the coated compacts in an atmosphere that reacts with the coating and/or the compact at pressing temperatures and pressures to cause the compact to approach theoretical density. The method is suitable for forming a fired ceramic compact having a whisker loading in excess of about 12.5 volume percent with substantially isotropic properties due to a substantially random orientation of the whiskers.

Abstract: A ceramic composition comprising a polycrystalline alumina matrix having titanium carbide whiskers distributed therein. The composition comprises 50 to 90 volume percent high purity alumina, 10 to 50 volume percent signal crystal titanium carbide whiskers, and up to 3 volume percent being the residue of sintering aids.

Abstract: A method of surface alloying a sialon article containing beta-prime-sialon phase (Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z). The method includes the steps of applying an alumina coating to the surface of the sialon article by chemical vapor deposition and then heat treating the coated article at a temperature between about 1300 and 1800 degrees Centigrade for a time sufficient to diffuse some or all of the aluminum and oxygen from the alumina coating into the sialon composition to produce a layer containing beta-prime-sialon phase having an increased Z value compared to the beta-prime-sialon phase in the remainder of the article.

Abstract: A sialon ceramic material comprising a ceramic core selected from alpha-prime-sialon, beta-prime-sialon, and an intergranular phase and, optionally substantially substantially inert refractory phases. The sialon ceramic material has an alloyed surface layer with a substantially increased aluminum and oxygen content.

Abstract: A ceramic composition comprising a polycrystalline alumina matrix having titanium carbide whiskers distributed therein. The composition comprises 50 to 90 volume percent high purity alumina, 10 to 50 volume percent single crystal titanium carbide whiskers, and up to 3 volume percent being the residue of sintering aids.

Abstract: A ceramic composite is provided possessing a combination of high fracture toughness, high hardness and high wear resistance. The composite contains SiC particles dispersed in a ceramic matrix of mainly sialon. The sialon is composed of about 10 to 67 weight percent alpha prime sialon, with the remainder, being beta prime sialon.

Abstract: A method of manufacturing a shaped ceramic article by hot isostatic pressing comprising the following steps: (a) forming a compact of sinterable ceramic compositions, (b) applying a coating to the compact by vapor deposition of a ceramic composition that does not become vitreous before or during the subsequent isostatic pressing step, and (c) heating and isostatically pressing the coated compacts in an atmosphere that reacts with the coating and/or the compact at pressing temperatures and pressures to cause the compact to approach theoretical density. The method is suitable for forming a fired ceramic compact having a whisker loading in excess of about 12.5 volume percent with substantially isotropic properties due to a substantially random orientation of the whiskers.

Abstract: An article of manufacture is provided having a SiC whisker reinforced alumina matrix substrate which has an alumina coating bonded to its exterior surface. It has been found that these articles are useful as cutting inserts in the high speed rough machining of steels.