Abstract: A cermet thermal spray powder generates a dense sprayed coating with superior wear resistance, superior toughness, superior resistance to molten metal, and superior resistance to thermal shock. The cermet thermal spray powder is sprayed onto a surface of a roller for a molten metal plating bath, wherein the powder includes: a first boride including W; a second boride including Cr; binder alloy particles including at least W, Cr, and Co; and unavoidable impurities; the content of B being 4.5% by mass to 8.5% by mass and the content of W being 50% by mass to 85% by mass with respect to 100% by mass of the cermet thermal spray powder.

Abstract: A cermet thermal spray powder generates a dense sprayed coating with superior wear resistance, superior toughness, superior resistance to molten metal, and superior resistance to thermal shock. The cermet thermal spray powder is sprayed onto a surface of a roller for a molten metal plating bath, wherein the powder includes: a first boride including W; a second boride including Cr; binder alloy particles including at least W, Cr, and Co; and unavoidable impurities; the content of B being 4.5% by mass to 8.5% by mass and the content of W being 50% by mass to 85% by mass with respect to 100% by mass of the cermet thermal spray powder.

Abstract: The hearth roll includes a thermally sprayed coating formed on the surface thereof. The thermally sprayed coating includes a nitride, an oxide, or a multiple oxide, and a matrix material composed of one or two or more metals. In the hearth roll having high Mn build-up resistance, the following expressions are satisfied: 3% by volume?X1?50% by volume; 3% by volume?X2?50% by volume; and 40% by volume?X1+X2?80% by volume, in which X1 is the percentage by volume of the nitride contained in the thermally sprayed coating with respect to the total volume (10% by volume) of the thermally sprayed coating, and X2 is the percentage by volume of the oxide or the multiple oxide contained in the thermally sprayed coating with respect to the total volume of the thermally sprayed coating.

Abstract: The hearth roll includes a thermally sprayed coating formed on the surface thereof. The thermally sprayed coating includes a nitride, an oxide, or a multiple oxide, and a matrix material composed of one or two or more metals. In the hearth roll having high Mn build-up resistance, the following expressions are satisfied: 3% by volume?X1?50% by volume; 3% by volume?X2?50% by volume; and 40% by volume?X1+X2?80% by volume, in which X1 is the percentage by volume of the nitride contained in the thermally sprayed coating with respect to the total volume (10% by volume) of the thermally sprayed coating, and X2 is the percentage by volume of the oxide or the multiple oxide contained in the thermally sprayed coating with respect to the total volume of the thermally sprayed coating.

Abstract: A long-life hearth roll having excellent build-up resistance against Mn-based substances, and which has excellent thermal shock resistance and abrasion resistance is provided. The thermal spray material that is thermally sprayed onto a surface of the hearth roll is characterized by including a heat resistant metal (including an alloy) that includes Al and can be used at 900° C. or more, and a complex oxide of one kind or two kinds or more of a rare earth element (Sc, Y, lanthanum, and lanthanoids) and a transition metal excluding group 3A of the periodic table, Zr, Hf, and Fe, wherein when an Al content is A (moles), and a rare earth element (Sc, Y, lanthanum, and lanthanoids) content is B (moles), the thermal spray material satisfies a condition of 0.3?(A/B)?4.0.

Abstract: Disclosed is a hearth roll having excellent build-up resistance against an Mn-containing substance, excellent thermal shock resistance, excellent wear resistance and a long lifetime. Specifically disclosed is a thermal spraying material to be thermally sprayed on the surface of a hearth roll. The thermal spraying material comprises: a heat-resistant metal (including an alloy) which contains Al and can be used at a temperature equal to or higher than 900° C.; and a multiple oxide of at least one metal selected from rare earth elements (Sc, Y, lanthanum and lanthanoid), metals belonging to Group 3A on the periodic table and transition metals excluding Zr, Hf and Fe, wherein the content of Al (A) (mole) and the content of the rare earth clement (Sc, Y, lanthanum and lanthanoid) (B) (mole) fulfill the requirement represented by the following formula: 0.3?(A/B)?4.0.