Abstract: End mills are disclosed which may be made monolithically of ceramic or other materials. The cutting portions of the end mills have lengths of cut that are no more than twice their cutting diameters and cores which are at least 0.7 times their cutting diameters. Their axial blades have cutting edges with negative radial rake and are separated by helical flutes. Their cutting ends have negative axial rake and are gashed ahead of center and have radial cutting edges with negative rake. Such end mills also have radiused corners and gashes transitioning from radial to axial at a flute. Methods of milling materials using such ceramic end mills are also disclosed.

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: 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: End mills are disclosed which may be made monolithically of ceramic or other materials. The cutting portions of the end mills have lengths of cut that are no more than twice their cutting diameters and cores which are at least 0.7 times their cutting diameters. Their axial blades have cutting edges with negative radial rake and are separated by helical flutes. Their cutting ends have negative axial rake and are gashed ahead of center and have radial cutting edges with negative rake. Such end mills also have radiused corners and gashes transitioning from radial to axial at a flute. Methods of milling materials using such ceramic end mills are also disclosed.

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: Additions of substitutional transition metal elements are made to improve the densifiability of titanium diboride while eliminating or minimizing the presence of deleterious grain boundary phases in the resultant bulk titanium diboride articles.

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: Additions of substitutional transition metal elements are made to improve the densifiability of titanium diboride while eliminating or minimizing the presence of deleterious grain boundary phases in the resultant bulk titanium diboride articles.

Abstract: A ceramic body that includes between about 15 volume percent and about 35 volume percent of a boron carbide irregular-shaped phase, and at least about 50 volume percent alumina, and the ceramic body has a fracture toughness (KIC, 18.5 Kg Load E&C) greater than or equal to about 4.5 MPa·m0.5.

Abstract: A process for making a ceramic body that includes the following steps: providing a starting powder mixture, the starting powder mixture comprises between about 15 volume percent and about 35 volume percent boron carbide powder and at least about 50 volume percent alumina powder and no more than about 5 volume percent of a sintering aid; and consolidating the powder mixture at a temperature equal to between about 1400 degrees Centigrade and 1850 degrees Centigrade to achieve a ceramic with a density equal to greater than 99 percent of theoretical density.

Abstract: A ceramic body, as well as a method for making the same, wherein the ceramic body contains aluminum oxynitride and whiskers, (and optionally) one or more of titanium carbonitride, and/or alumina, and/or zirconia, and/or other component(s).

Abstract: A method of machining a workpiece including the steps of providing a workpiece; providing a ceramic cutting insert having a rake surface and a flank surface wherein the rake surface and the flank surface intersect to form a cutting edge and the ceramic cutting insert having a substrate that comprises between about 15 volume percent and about 35 volume percent of a boron carbide phase and at least about 50 volume percent alumina and has a fracture toughness (KIC, 18.5 Kg Load E&C) greater than or equal to about 4.5 MPa·m0.5; causing relative rotational movement between the workpiece and the ceramic cutting insert wherein the surface speed of the relative rotational movement is equal to or greater than about 457 surface meters per minute; and bringing the ceramic cutting insert and the workpiece into contact with each other so as to remove material from the workpiece.

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 two selected rare earth elements to the SiAlON ceramic body wherein the selected 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. The SiAlON ceramic body includes a two phase composite that includes an alpha prime SiAlON phase and a beta prime SiAlON phase wherein the alpha prime SiAlON phase contains one or more of the selected rare earth elements excluding La and Ce. The silicon nitride powder makes up at least about 70 weight percent of the starting powder mixture wherein the beta-silicon nitride content of the silicon nitride powder has a lower limit equal to zero weight percent and an upper limit equal to about 1.

Abstract: A ceramic body, as well as a method for making the same, wherein the ceramic body contains aluminum oxynitride and whiskers, (and optionally) one or more of titanium carbonitride, and/or alumina, and/or zirconia, and/or other component(s).

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: A ceramic body, as well as a method of making the ceramic body, wherein in one aspect a hot-pressing method is used to produce the ceramic body. In another aspect, a sintering to full density method is used to produce the ceramic body. The hot-pressed ceramic body contains between about 15 volume percent and about 35 volume percent of a boron carbide phase and at least about 50 volume percent of alumina, and the substrate has a fracture toughness (KIC, 18.5 Kg Load E&C) greater than or equal to about 4.5 MPa·m0.5. The sintered to full density ceramic body contains between about 15 volume percent and about 50 volume percent of a boron carbide irregular-shaped phase and at least about 50 volume percent alumina.

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: 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.