Abstract: The invention concerns a sintered ceramic component of silicon nitride or sialon suitable as rolling element in a bearing and a manufacturing method for making such ceramic components. The ceramic component has high density and a homogeneous and fine microstructure, giving the component excellent mechanical properties. Manufacturing of the sintered ceramic component by SPS is cost-effective and rapid.

Abstract: Industrial blast nozzles are disclosed which have liners made, at least in part, from a SiAlON-containing ceramic material which has a surface resistance of about 12 megaOhms or less and an erosion rate of about 1.9×10?4 cm3/g or less. The SiAlON-containing ceramic material preferably contains a two-phase SiAlON, silicon carbide, and a conductive phase that is one or more of titanium nitride, tantalum nitride, zirconium nitride, and titanium carbide.

Abstract: A SiAlON armor ceramic made from a starting powder mixture including silicon nitride powder. The armor ceramic includes a ceramic body that has between about 64 weight percent and about 90 weight percent alpha SiAlON phase that contains an alpha SiAlON-bound rare earth element. The ceramic body also has between about 5 weight percent and about 35 weight percent of a beta SiAlON phase of the formula Si6?zAlzOzN8?z wherein the value of “z” ranges between about 0.10 and about 0.35. The alpha SiAlON-bound rare earth element in the alpha SiAlON phase is present as a result of the starting powder mixture that contains between about 1 weight percent and about 7 weight percent of an oxide of the alpha SiAlON-bound rare earth element. The ceramic body has a fracture toughness (KIC) greater than about 6.00 MPa·m1/2 and a Vickers hardness (HVN) equal to greater than about 19.3 GPa.

Abstract: The invention concerns a sintered ceramic component of silicon nitride or sialon suitable as rolling element in a bearing and a manufacturing method for making such ceramic components. The ceramic component has high density and a homogeneous and fine microstructure, giving the component excellent mechanical properties. Manufacturing of the sintered ceramic component by SPS is cost-effective and rapid.

Abstract: A cutting insert 1 is made of an aluminum oxide-based composite sintered body constituted by a ternary ceramic material including aluminum oxide, silicon carbide, and a sialon. The sialon in the aluminum oxide-based composite sintered body is Si—Al—O—N as defined by JCPDS No. 32-0026 in X-ray diffraction analysis.

Abstract: A SiAlON ceramic armor made from a starting powder mixture. The ceramic armor contains between about 60 weight percent and about 98 weight percent alpha SiAlON phase that contains an alpha SiAlON-bound rare earth element and between about 2 weight percent and about 40 weight percent of a beta SiAlON phase of the formula Si6?zAlzOzN8?z wherein the value of “z” ranges between about 0.2 and about 1.0. The ceramic armor further comprising sintering aid residue present as a result of the starting powder mixture containing between about 4 weight percent and about 14 weight percent of an oxide of an alpha SiAlON-bound rare earth element. The ceramic armor has a fracture toughness (KIC) greater than about 6.00 M·Pa m1/2 and a Vickers hardness (HVN) equal to greater than about 17.5 GPa.

Abstract: A silicon nitride sintered body comprising ?-sialon expressed by a composition formula of Si6?ZAlZOZN8?Z, wherein z value being the dissolved amount is 0.1 to 1, as a main phase, a grain boundary phase and Fe silicide particles. The grain boundary phase contains RE (Group III elements in the periodic table)-Al—Si—O, and component ratios of Al, Si and RE in terms of Al2O3, SiO2, RE2O3, respectively is 5 to 50 mass % of Al2O3, 5 to 20 mass % of SiO2, and the balanced amount of RE2O3, the grain boundary phase is contained in a range of 20 volume % or less to 100 volume % of the sintered body, and the Fe silicide particles is contained in 0.02 to 3 mass % in terms of Fe to 100 mass % of the sintered body. Its high thermal shock resistance provides suitable applications to members for molten metal, hot working, and digging.

Abstract: Geopolymer composite materials having low coefficient of thermal expansion are disclosed. The materials are useful in high temperature applications due to their low coefficient of thermal expansion and high strength. Also disclosed is a boron modified water glass geopolymer composition that is compatible with ceramic particulate material such as cordierite and fused silica. The geopolymer composite may be extruded to form structures such as honeycomb monoliths, flow filters or used as a plugging or skinning cement and may be fired at temperatures at or below 1100° C. Both the structures and the cement have high green and fired strength, a low coefficient of thermal expansion, and good acid durability. The cost of manufacturing objects using the material of the present invention is substantially reduced, in comparison with typically production methods of cordierite based bodies, due to the substantially shortened firing times.

Abstract: A material based on SiAlON contain 70-97 vol. % of alpha and beta-SiAlON and an amorphous or partially crystalline grain boundary phase and 3 to 30 vol.% of a hard material. The material has an alpha-SiAlON gradient which decreases from the outside to the inside.

Abstract: A sintered ceramic material comprises a crystalline phase and an intergranular phase comprising a glass phase. The material is manufactured from a starting powder being mixed with an additive comprising one or more metal from a group of Li, Na, Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Th, Pa or U. The additive is in non oxide form, or in a form which transforms to a metal or nitride during a synthesis in nitrogen atmosphere and the resulting glass phase having a high nitrogen content with a N:O ratio higher than 35:65 and a glass transition temperature above 950° C.

Abstract: A method of making a SiAlON ceramic body that includes a two phase composite comprising an alpha prime SiAlON phase and a beta prime SiAlON phase, the method includes the steps of: providing a starting powder that comprises at least about 70 weight percent silicon nitride powder and one or more other powders that provide aluminum, oxygen, nitrogen, and at least two selected rare earth elements to the SiAlON ceramic body wherein the rare earth elements are selected from at least two groups of the following three groups of rare earth elements wherein Group I comprises La, Ce, Pr, Nd, Pm, Sm and Eu, and Group II comprises Gd, Tb, Dy and Ho, and Group III comprises Er, Tm, Yb and Lu; and consolidating the starting powder mixture to form a ceramic body comprising a two phase composite comprising an alpha prime SiAlON phase and a beta prime SiAlON phase, and the alpha prime SiAlON phase containing one or more of the selected rare earth elements excluding La and Ce, and the ceramic body having a composition falling

Abstract: Ceramic plates for side dams of twin-drum continuous strip casters comprising a REAG phase of 10 to 90 vol. %, a Sialon phase of 5 to 50 vol. %, a BN phase of 5 to 50 vol. % and an amorphous phase of over 0 to 20 vol. %, with the REAG phase comprising at least one rare-earth aluminum garnet phase selected from YAG, ErAG, YbAG and DyAG phases and the Sialon phase having a chemical formula, Si6?zAlzOzN8?z, wherein Z is between 0.05 and 1.9.

Abstract: The present invention consists of a synergistic mixture of Si3N4, Al2O3, AlN, SiO2 and Nd2O3. The cost effective synergistic composition is useful for the preparation of dense neodymium stabilised ?-Si3N4-?-SiAlON composite of the order of >98% theoretical density, having high hardness and high fracture toughness. The dense ?-Si3N4-?-SiAlON composite will be useful for low temperature applications as wear parts like bearing and roller materials and particularly for grinding and milling operations like grinding balls.

Abstract: The present invention provides a process for the manufacture of dense neodymium stabilized ?-Si3N4-?-SiAlON composite, wherein a synergistic composition essentially consisting of Si3N4, Al2O3, AlN, SiO2 and Nd2O3 as starting materials is mixed in proportion to make a total of 100 mole in the mixed batch, passing the powder through 100 mesh, pressing the powder to form green compacts, sintering the green compacts at a temperature in the range of 1700° to 1900° C. in nitrogen atmosphere. The process of the present invention provides neodymium stabilized ?-Si3N4-?-SiAlON composites by processing a composition from the system Si3N4—Al2O3.AlN—Nd2O3.9AlN—SiO2 resulting into dense product of the order of >98% theoretical density with the advantages such as cost effectiveness, high hardness and high fracture toughness.

Abstract: A method for making a crystallized ceramic body containing a two phase composite comprising an alpha prime SiAlON phase that contains ytterbium and a beta prime SiAlON phase, the process includes the steps of: blending together a starting powder mixture that upon densification forms the SiAlON ceramic, the starting powder includes at least about 70 weight percent silicon nitride powder wherein the silicon nitride powder contains beta silicon nitride in an amount less than or equal to about 1.

Abstract: This invention is about SiALON ceramics comprising an alpha SiAlON, a beta SiAlON and an intergranular amorphous and/or crystalline phase. Said alpha SiALON phase was prepared from a multi-cationic mixture including the element of calcium, at least one of yttrium and/or a rare earth element with atomic number greater than 62 and at least one of a rare earth element with atomic number equal or smaller than 62. The second phase, beta SiALON contains elements of Si, Al, O, N. The third phase, amorphous and/or crystalline intergranular phase contains in addition to elements of Si, AL, O, N, element of calcium, at least one of yttrium and/or a rare earth element with atomic number greater than 62 and at least one of a rare earth element with atomic number equal or smaller than 62. This material with its toughness, high fracture resistance and high temperature resistance is useful for cutting tool applications and components in machinery and engines.

Abstract: A SiAlON ceramic body made from a starting powder mixture that includes silicon nitride powder, and one or more powders that provide aluminum, oxygen, nitrogen and ytterbium to the SiAlON ceramic. The SiAlON ceramic body includes a two phase composite comprising alpha prime SiAlON phase, which is present in an amount greater than or equal to about 20 weight percent of the two phase composite, and a beta prime SiAlON phase wherein the alpha prime SiAlON phase containing ytterbium therein. The starting silicon nitride powder contains less than or equal to about 1.6 weight percent beta-silicon nitride. The ceramic body further includes an intergranular phase that includes an intergranular crystalline phase comprising at least one of YbAG and J-phase. The overall composition of the ceramic body is YbaSibAlcOdNe, wherein when a is less than 0.05, the relative intensity of the peak associated with either one or both intergranular crystalline phases of YbAG and J-phase is greater than about 2.

Abstract: A SiAlON material that includes a two phase composite of an alpha prime SiAlON phase and a beta prime SiAlON phase. The alpha prime phase contains ytterbium. The alpha prime SiAlON phase being present in an amount between about 25 weight percent and about 85 weight percent of the two phase composite. The SiAlON material further includes an intergranular phase.

Abstract: This invention is about SiALON ceramics comprising an alpha SiAlON, a beta SiAlON and an intergranular amorphous and/or crystalline phase. Said alpha SiALON phase was prepared from a multi-cationic mixture including the element of calcium, at least one of yttrium and/or a rare earth element with atomic number greater than 62 and at least one of a rare earth element with atomic number equal or smaller than 62. The second phase beta SiALON contains elements of Si, AL, O, N. The third phase, amorphous and/or crystalline intergranular phase contains in addition to elements of Si, AL, O, N, element of calcium, at least one of yttrium and/or a rare earth element with atomic number greater than 62 and at least one of a rare earth element with atomic number equal or smaller than 62. This material with its toughness, high fracture resistance an high temperature resistance is useful for cutting tool applications and components in machinery and engines.

Abstract: A SiAlON material that includes a two phase composite of an alpha prime SiAlON phase and a beta prime SiAlON phase. The alpha prime phase contains ytterbium. The alpha prime SiAlON phase being present in an amount between about 25 weight percent and about 85 weight percent of the two phase composite. The SiAlON material further includes an intergranular phase.

Abstract: The present invention provides a composite pressure-sintered material comprising a continuous phase of hexagonal boron nitride and, dispersed therein, a second material comprising (a) at least one metal nitride selected from the group consisting of silicon, aluminium and titanium nitrides and (b) at least one stable metal oxide; wherein the amount of metal oxide is such that the second material does not contain more than 35% by weight of oxygen. This material possesses a low thermal expansion coefficient and therefore reveals good thermal shock resistance. Another characteristic of this material is its low wettability by molten steel which is thus responsible for excellent chemical resistance to liquid metal. Finally, this material is exceptionally mechanical wear resistant.

Abstract: Molybdenum disilicide/&bgr;′-Si6−zAlzOzN8−z, wherein z=a number from greater than 0 to about 5, composites are made by use of in situ reactions among &agr;-silicon nitride, molybdenum disilicide, and aluminum. Molybdenum disilicide within a molybdenum disilicide/&bgr;′-Si6−zAlzOzN8−z eutectoid matrix is the resulting microstructure when the invention method is employed.

Abstract: Molybdenum disilicide/&bgr;′-Si6-zAlzOzN8-z, wherein z=a number from greater than 0 to about 5, composites are made by use of in situ reactions among &agr;-silicon nitride, molybdenum disilicide, and aluminum. Molybdenum disilicide within a molybdenum disilicide/&bgr;′-Si6-zAlzOzN8-z eutectoid matrix is the resulting microstructure when the invention method is employed.