Hexavalent chromium-free slurries are provided that are capable of achieving a full cure at temperatures as low as 330-450 degrees F., thus making the coatings especially suitable for application on temperature sensitive base materials. The slurries are suitable in the production of protective coating systems formed by novel silicate-based basecoats that are sealed with novel phosphate-based topcoats. The coating systems exhibit acceptable corrosion and heat resistance and are capable of replacing traditional chromate-containing coating systems.

A lead-free insulating ceramic coating zinc oxide arrester valve and a method for manufacturing thereof are disclosed. In an embodiment a method includes preparing an initial powder from starting materials with the following mass percentages: ZnO: 86-95%; Bi2O3: 1.0-3.0%; Co3O4: 0.5-1.5%; Mn3O4: 0.2-1.0%; Sb2O3: 3.0-9.0 %; NiO: 0.2-1.0%; and SiO2: 1.0-3.0%, preparing a ceramic coating powder by mixing the initial powder, deionized water and first grinding balls, milling the mixture, and drying and pulverizing the mixture, preparing a ceramic coating slurry by mixing a PVA solution, the ceramic coating powder and second grinding balls and milling the mixture, applying the ceramic coating slurry to a green body, heating and debinding the ceramic coating slurry with the green body thereby forming a resistor element and sintering the resistor element thereby obtaining a zinc oxide surge arrester valve block having a lead-free insulating ceramic coating.

A lead-free insulating ceramic coating zinc oxide arrester valve and a method for manufacturing thereof are disclosed. In an embodiment a method includes preparing an initial powder from starting materials with the following mass percentages: ZnO: 86-95%; Bi2O3: 1.0-3.0%; Co3O4: 0.5-1.5%; Mn3O4: 0.2-1.0%; Sb2O3: 3.0-9.0 %; NiO: 0.2-1.0%; and SiO2: 1.0-3.0%, preparing a ceramic coating powder by mixing the initial powder, deionized water and first grinding balls, milling the mixture, and drying and pulverizing the mixture, preparing a ceramic coating slurry by mixing a PVA solution, the ceramic coating powder and second grinding balls and milling the mixture, applying the ceramic coating slurry to a green body, heating and debinding the ceramic coating slurry with the green body thereby forming a resistor element and sintering the resistor element thereby obtaining a zinc oxide surge arrester valve block having a lead-free insulating ceramic coating.

A method for additive manufacturing of a composite object containing a bonded network of boron carbide particles and aluminum occupying spaces between boron carbide particles, the method comprising: (i) producing a porous preform constructed of boron carbide by an additive manufacturing process in which particles of boron carbide are bonded together; and (ii) infiltrating molten aluminum, at a temperature of 1000-1400 C., into pores of said porous preform to produce said composite object constructed of boron carbide particles within an aluminum matrix, wherein the boron carbide is present in the composite object in an amount of 30-70 wt. %. The resulting composite material is also herein described.

A method for additive manufacturing of a composite object containing a bonded network of boron carbide particles and aluminum occupying spaces between boron carbide particles, the method comprising: (i) producing a porous preform constructed of boron carbide by an additive manufacturing process in which particles of boron carbide are bonded together; and (ii) infiltrating molten aluminum, at a temperature of 1000-1400 C., into pores of said porous preform to produce said composite object constructed of boron carbide particles within an aluminum matrix, wherein the boron carbide is present in the composite object in an amount of 30-70 wt. %. The resulting composite material is also herein described.

The present invention provides an aluminum-diamond composite which combines high thermal conductivity and a coefficient of thermal expansion close to a semiconductor element, and in which the difference between the thicknesses of both surfaces is reduced so as to be suitable for use as a heat sink etc. for a semiconductor element. Provided is a flat plate-shaped aluminum-diamond composite that has an aluminum-diamond composite part and a surface layer that coats both surfaces of the composite part and includes a metal that has aluminum as a principal component, wherein: the composite part is composed of a composite material that is composed of an aluminum or aluminum alloy matrix and diamond particles dispersed in said matrix; the composite material is composed of a diamond powder in which diamond particles having a particle size of 1-20 m, inclusive, make up 10-40 vol % of the diamond particles and diamond particles having a particle size of 100-250 m, inclusive, make up 50-80 vol %, said powder not containing diamond particles having a particle size of less than 1 m or diamond particles having a particle size of more than 250 m; and the average value for the differences in in-plane thickness per 50 mm50 mm is 100 m or less.

The present invention provides an aluminum-diamond composite which combines high thermal conductivity and a coefficient of thermal expansion close to a semiconductor element, and in which the difference between the thicknesses of both surfaces is reduced so as to be suitable for use as a heat sink etc. for a semiconductor element. Provided is a flat plate-shaped aluminum-diamond composite that has an aluminum-diamond composite part and a surface layer that coats both surfaces of the composite part and includes a metal that has aluminum as a principal component, wherein: the composite part is composed of a composite material that is composed of an aluminum or aluminum alloy matrix and diamond particles dispersed in said matrix; the composite material is composed of a diamond powder in which diamond particles having a particle size of 1-20 m, inclusive, make up 10-40 vol % of the diamond particles and diamond particles having a particle size of 100-250 m, inclusive, make up 50-80 vol %, said powder not containing diamond particles having a particle size of less than 1 m or diamond particles having a particle size of more than 250 m; and the average value for the differences in in-plane thickness per 50 mm50 mm is 100 m or less.

An intermetallic matrix composite has an intermetallic matrix and a ceramic reinforcement. The intermetallic matrix comprises, in atomic percent: 28.02.0 Nb; 27.02.0 Mo; 27.02.0 Cr; 9.0 2.0 Si; 9.0 2.0 Al; and no more than 10.0 other alloying elements and impurities, if any.

An intermetallic matrix composite has an intermetallic matrix and a ceramic reinforcement. The intermetallic matrix comprises, in atomic percent: 28.02.0 Nb; 27.02.0 Mo; 27.02.0 Cr; 9.0 2.0 Si; 9.0 2.0 Al; and no more than 10.0 other alloying elements and impurities, if any.

A lead-free insulating ceramic coating zinc oxide arrester valve and a method for manufacturing thereof are disclosed. In an embodiment a method includes preparing an initial powder from starting materials with the following mass percentages: ZnO: 86-95%; Bi.sub.2O.sub.3: 1.0-3.0%; Co.sub.3O.sub.4: 0.5-1.5%; Mn.sub.3O.sub.4: 0.2-1.0%; Sb.sub.2O.sub.3: 3.0-9.0%; NiO: 0.2-1.0%; and SiO.sub.2: 1.0-3.0%, preparing a ceramic coating powder by mixing the initial powder, deionized water and first grinding balls, milling the mixture, and drying and pulverizing the mixture, preparing a ceramic coating slurry by mixing a PVA solution, the ceramic coating powder and second grinding balls and milling the mixture, applying the ceramic coating slurry to a green body, heating and debinding the ceramic coating slurry with the green body thereby forming a resistor element and sintering the resistor element thereby obtaining a zinc oxide surge arrester valve block having a lead-free insulating ceramic coating.