Abstract: Refractory ceramics and composite materials consisting of nitrides, mixed nitrides and oxides, and oxynitrides of Group IV metals Hf, Zr, Ti, and Group III metals Sc, Y, and lanthanides La through Lu, are used to form refractory articles, or as coatings for refractory articles. These materials and articles have high resistance to molten metals, molten salts, erosion, and high temperature corrosive environments, and can be engineered to have desirable thermal and electrical properties. In particular the articles are crucibles, molds, containment vessels, and spray nozzles, and most particularly these articles are made of or coated with the Hf compounds.

Abstract: Refractory ceramics and composite materials consisting of nitrides, mixed nitrides and oxides, and oxynitrides of Group IV metals Hf, Zr, Ti, and Group III metals Sc, Y, and lanthanides La through Lu, are used to form refractory articles, or as coatings for refractory articles. These materials and articles have high resistance to molten metals, molten salts, erosion, and high temperature corrosive environments, and can be engineered to have desirable thermal and electrical properties. In particular the articles are crucibles, molds, containment vessels, and spray nozzles, and most particularly these articles are made of or coated with the Hf compounds.

Abstract: Electron emission materials consisting of carbides, borides, and oxides, and related mixtures and compounds, of Group IVB metals Hf, Zr, and Ti, Group IIA metals Be, Mg, Ca, Sr, and Ba, and Group IIIB metals Sc, Y, and lanthanides La through Lu are used in electrodes. The electron emission materials include ternary Group IVB-IIIB, IVB-IIA, and IIIB-IIA oxides and quaternary Group IVB-IIIB-IIA oxides. These electron emission materials are typically contained in a refractory metal matrix formed of tungsten, molybdenum, tantalum, rhenium, and their alloys, but may also be used by themselves. These materials and electrodes have high melting points, low vapor pressures, low work functions, high electrical and thermal conductivity, and high thermionic electron emission and field emission properties.

Abstract: Electron emission materials consisting of carbides, borides, and oxides, and related mixtures and compounds, of Group IVB metals Hf, Zr, and Ti, Group IIA metals Be, Mg, Ca, Sr, and Ba, and Group IIIB metals Sc, Y, and lanthanides La through Lu are used in electrodes. The electron emission materials include ternary Group IVB-IIIB and IVB-IIA oxides. These electron emission materials are typically contained in a refractory metal matrix formed of tungsten, tantalum, rhenium, and their alloys, but may also be used by themselves. These materials and electrodes have high melting points, low vapor pressures, low work functions, high electrical and thermal conductivity, and high thermionic electron emission and field emission properties.

Abstract: Refractory ceramics and composite materials consisting of nitrides, carbides, mixed carbides and oxides, oxycarbides, mixed nitrides and oxides, and oxynitrides of Group IVB metals Hf, Zr, and Ti, Group IIA metals Be, Mg, Ca, Sr, and Ba, and Group IIIB metals Sc, Y, and lanthanides La through Lu are used to form refractory articles, or as coatings for refractory articles. These materials and articles have high resistance to molten metals, molten salts, erosion, and high temperature corrosive environments, and can be engineered to have desirable thermal and electrical properties. The refractory materials encompass nitrides, carbides, reacted ternary and quaternary oxides, mixed carbides and oxides, oxycarbides, mixed nitrides and oxides, and oxynitrides and have the general chemical formula M.sub.x1 M'.sub.x2 M".sub.x3 N.sub.y C.sub.w O.sub.z where M is Hf, Zr, or Ti, M' is Be, Mg, Ca, Sr, or Ba, M" is Sc, Y, and lanthanides La through Lu, N is nitrogen, C is carbon, O is oxygen.

Abstract: Electron emission materials consisting of carbides, borides, and oxides, and related mixtures and compounds, of Group IVB metals Hf, Zr, and Ti, Group IIA metals Be, Mg, Ca, Sr, and Ba, and Group IIIB metals Sc, Y and lanthanides La through Lu are used in electrodes. These electron emission materials are typically contained in a refractory metal matrix formed of tungsten, tantalum, rhenium, and their alloys, but may also be used by themselves. These materials and electrodes have high melting points, low vapor pressures, low work functions, high electrical and thermal conductivity, and high thermionic electron emission and field emission properties.

Abstract: Neutron absorbing refractory B.sub.4 C-Gd and Gd.sub.2 O.sub.3 -Gd cermets, B.sub.4 C-Gd and Gd.sub.2 O.sub.3 -Gd metal-matrix composites, and B.sub.4 C-Gd.sub.2 O.sub.3 ceramic-ceramic composites can be manufactured by applying fundamental thermodynamic and kinetic guidelines as processing principals.Three steps are involved in the fabrication of these new compositions of matter. First, the starting materials are consolidated into a compacted porous green body. Next, the green body is densified using the appropriate method depending on the class of material sought: cermet, metal-matrix composite, or ceramic-ceramic composite. Finally, either during the densification process or by subsequent heat treatment, new phase evolution is obtained via interfacial chemical reactions occurring in the microstructures.The existence of a new phase has been identified in B.sub.4 C-Gd and B.sub.4 C-Gd.sub.2 O.sub.3 composites.

Abstract: Neutron absorbing refractory B.sub.4 C--Gd and Gd.sub.2 O.sub.3 --Gd cermets, B.sub.4 C--Gd and Gd.sub.2 O.sub.3 --Gd metal-matrix composites, and B.sub.4 C--Gd.sub.2 O.sub.3 ceramic-ceramic composites can be manufactured by applying fundamental thermodynamic and kinetic guidelines as processing principals.Three steps are involved in the fabrication of these new compositions of matter. First, the starting materials are consolidated into a compacted porous green body. Next, the green body is densified using the appropriate method depending on the class of material sought: cermet, metal-matrix composite, or ceramic-ceramic composite. Finally, either during the densification process or by subsequent heat treatment, new phase evolution is obtained via interfacial chemical reactions occurring in the microstructures.The existence of a new phase has been identified in B.sub.4 C--Gd and B.sub.4 C--Gd.sub.2 O.sub.3 composites.