A ceramic body is provided that is suitable for use in dental applications to provide a natural aesthetic appearance. A colorized ceramic body is formed that has at least one color region and a color gradient region. A ceramic body is formed having at least two color regions and a color gradient that forms a transition region between two color regions. A method for making the colorized ceramic body includes unidirectional infiltration of a coloring composition into the ceramic body.

A ceramic body is provided that is suitable for use in dental applications to provide a natural aesthetic appearance. A colorized ceramic body is formed that has at least one color region and a color gradient region. A ceramic body is formed having at least two color regions and a color gradient that forms a transition region between two color regions. A method for making the colorized ceramic body includes unidirectional infiltration of a coloring composition into the ceramic body.

A ceramic body is provided that is suitable for use in dental applications to provide a natural aesthetic appearance. A colorized ceramic body is formed that has at least one color region and a color gradient region. A ceramic body is formed having at least two color regions and a color gradient that forms a transition region between two color regions. A method for making the colorized ceramic body includes unidirectional infiltration of a coloring composition into the ceramic body.

A glass furnace including an additive-containing product including an additive selected from: phosphorus compounds other than glasses and vitroceramics, tungsten compounds other than glasses and vitroceramics, molybdenum compounds other than glasses and vitroceramics, iron in the form of metal, aluminum in the form of metal, silicon in the form of metal, and their mixtures, silicon carbide, boron carbide, silicon nitride, boron nitride, glasses including elemental phosphorus and/or iron and/or tungsten and/or molybdenum, vitroceramics including elemental phosphorus and/or iron and/or tungsten and/or molybdenum, and their mixtures, and having the following chemical analysis, exclusively of the additive, as a percentage by weight on the basis of the oxides: Cr.sub.2O.sub.32%, and Cr.sub.2O.sub.3+Al.sub.2O.sub.3+CaO+ZrO.sub.2+MgO+Fe.sub.2O.sub.3+SiO.sub.2+TiO.sub.290%, and Cr.sub.2O.sub.3+Al.sub.2O.sub.3+MgO60%, the content by weight of additive being in the range 0.01% to 6%.

A cutting tool comprises a rake face and a flank face, the cutting tool being composed of a substrate made of a cubic boron nitride sintered material and a coating provided on the substrate, the coating including a MAIN layer, the MAIN layer including crystal grains of M.sub.xAl.sub.1-xN in the cubic crystal system, n.sub.F<n.sub.R being satisfied, where n.sub.F represents a number of voids per 100 m in length of the MAIN layer on the flank face in a cross section of the MAIN layer, and n.sub.R represents a number of voids per 100 m in length of the MAIN layer on the rake face in a cross section of the MAIN layer, n.sub.D being 3 or less, where n.sub.D represents a number of droplets per 100 m in length of the MAIN layer on the flank face in a cross section of the MAIN layer.

A cutting tool comprises a rake face and a flank face, the cutting tool being composed of a substrate made of a cubic boron nitride sintered material and a coating provided on the substrate, the coating including a MAIN layer, the MAIN layer including crystal grains of M.sub.xAl.sub.1-xN in the cubic crystal system, n.sub.F<n.sub.R being satisfied, where n.sub.F represents a number of voids per 100 m in length of the MAIN layer on the flank face in a cross section of the MAIN layer, and n.sub.R represents a number of voids per 100 m in length of the MAIN layer on the rake face in a cross section of the MAIN layer, n.sub.D being 3 or less, where n.sub.D represents a number of droplets per 100 m in length of the MAIN layer on the flank face in a cross section of the MAIN layer.

Hexavalent chromium-free slurry formulations which are suitable in the production of ceramic overlay coating systems are described. The formulations provide superior hot corrosion and heat oxidation protection for superalloy substrates. A basecoat slurry and topcoat slurry are provided. The basecoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:PO.sub.4 higher than about 1:3 with the incorporation of metal oxide particles. The topcoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:PO.sub.4 higher than about 1:3. Both of the basecoat slurry and the topcoat slurry are hexavalent chromium-free.

A glass furnace including an additive-containing product including an additive selected from: phosphorus compounds other than glasses and vitroceramics, tungsten compounds other than glasses and vitroceramics, molybdenum compounds other than glasses and vitroceramics, iron in the form of metal, aluminum in the form of metal, silicon in the form of metal, and their mixtures, silicon carbide, boron carbide, silicon nitride, boron nitride, glasses including elemental phosphorus and/or iron and/or tungsten and/or molybdenum, vitroceramics including elemental phosphorus and/or iron and/or tungsten and/or molybdenum, and their mixtures, and having the following chemical analysis, exclusively of the additive, as a percentage by weight on the basis of the oxides: Cr.sub.2O.sub.3?2%, and Cr.sub.2O.sub.3+Al.sub.2O.sub.3+CaO+ZrO.sub.2+MgO+Fe.sub.2O.sub.3+SiO.sub.2+TiO.sub.2?90%, and Cr.sub.2O.sub.3+Al.sub.2O.sub.3+MgO?60%, the content by weight of additive being in the range 0.01% to 6%.

A ceramic body is provided that is suitable for use in dental applications to provide a natural aesthetic appearance. A colorized ceramic body is formed that has at least one color region and a color gradient region. A ceramic body is formed having at least two color regions and a color gradient that forms a transition region between two color regions. A method for making the colorized ceramic body includes unidirectional infiltration of a coloring composition into the ceramic body.

A ceramic body is provided that is suitable for use in dental applications to provide a natural aesthetic appearance. A colorized ceramic body is formed that has at least one color region and a color gradient region. A ceramic body is formed having at least two color regions and a color gradient that forms a transition region between two color regions. A method for making the colorized ceramic body includes unidirectional infiltration of a coloring composition into the ceramic body.