A coating material containing an oxyfluoride of yttrium and having a Fisher diameter of 1.0 to 10 μm and a tap density TD to apparent density AD ratio, TD/AD, of 1.6 to 3.5. The coating material preferably has a pore volume of pores with a diameter of 100 μm or smaller of 1.0 cm.sup.3/g or less as measured by mercury intrusion porosimetry. A coating containing an oxyfluoride of yttrium and having a Vickers hardness of 200 HV0.01 or higher. The coating preferably has a fracture toughness of 1.0×10.sup.2 Pa.Math.m.sup.1/2 or higher.

A coating material containing an oxyfluoride of yttrium and having a Fisher diameter of 1.0 to 10 μm and a tap density TD to apparent density AD ratio, TD/AD, of 1.6 to 3.5. The coating material preferably has a pore volume of pores with a diameter of 100 μm or smaller of 1.0 cm.sup.3/g or less as measured by mercury intrusion porosimetry. A coating containing an oxyfluoride of yttrium and having a Vickers hardness of 200 HV0.01 or higher. The coating preferably has a fracture toughness of 1.0×10.sup.2 Pa.Math.m.sup.1/2 or higher.

A thermal spray material that enables a thermal sprayed coating, which is capable of exhibiting the same performances as those of the related art, to be obtained more easily than the related art, and a method for forming a thermal sprayed coating using the thermal spray material are provided.

A thermal spray material which for forming a thermal sprayed coating containing a rare-earth oxyhalide includes a rare-earth halide powder and a rare-earth oxide powder.

A thermal spray material that enables a thermal sprayed coating, which is capable of exhibiting the same performances as those of the related art, to be obtained more easily than the related art, and a method for forming a thermal sprayed coating using the thermal spray material are provided.

A thermal spray material which for forming a thermal sprayed coating containing a rare-earth oxyhalide includes a rare-earth halide powder and a rare-earth oxide powder.

Provided is a slurry for suspension plasma spraying, which is a spray material used for suspension plasma spraying in an atmosphere including an oxygen-containing gas, contains 5-40 mass % of rare earth fluoride particles having a maximum particle diameter (D100) of 12 μm or less, and contains one or more types of solvent selected from among water and organic solvents. A rare earth acid fluoride-containing sprayed film, in which process shift and particle generation hardly occur, can be stably formed on a base material by carrying out suspension plasma spraying in an atmosphere including an oxygen-containing gas. A spraying member provided with this sprayed film exhibits excellent corrosion resistance to halogen-based gas plasma.

Provided is a slurry for suspension plasma spraying, which is a spray material used for suspension plasma spraying in an atmosphere including an oxygen-containing gas, contains 5-40 mass % of rare earth fluoride particles having a maximum particle diameter (D100) of 12 μm or less, and contains one or more types of solvent selected from among water and organic solvents. A rare earth acid fluoride-containing sprayed film, in which process shift and particle generation hardly occur, can be stably formed on a base material by carrying out suspension plasma spraying in an atmosphere including an oxygen-containing gas. A spraying member provided with this sprayed film exhibits excellent corrosion resistance to halogen-based gas plasma.

A sintered rare earth oxyfluoride compact is composed of Ln.sub.aO.sub.bF.sub.c (wherein Ln is a rare earth element; and a, b, and c each independently represent a positive number, provided that they are not equal to each other) or Ca-stabilized LnOF as a primary phase and LnOF unstabilized with Ca as a secondary phase. The intensity ratio of the XRD peak of the (018) or (110) plane of the unstabilized LnOF to the highest XRD peak of Ln.sub.aO.sub.bF.sub.c is preferably 0.5% to 30%.

Disclosed are a material for plasma spray coating having high plasma resistance and a method for producing the same. The method includes: feeding yttrium compound into an air plasma jet; melting the yttrium compound; and cooling droplets of the molten yttrium compound.

Disclosed are a material for plasma spray coating having high plasma resistance and a method for producing the same. The method includes: feeding yttrium compound into an air plasma jet; melting the yttrium compound; and cooling droplets of the molten yttrium compound.

A film-forming powder containing a rare earth oxyfluoride has an average particle size D50 of 0.6-15 m, a total volume of 10 m pores of 0.51-1.5 cm.sup.3/g as measured by mercury porosimetry, and a BET surface area of 3-50 m.sup.2/g is suitable for forming a dense film in high yields or deposition rates and high productivity. The film-forming powder having a greater pore volume can be prepared by forming a rare earth ammonium fluoride complex salt on surfaces of rare earth oxide particles to provide precursor particles, and heat treating the precursor particles at a temperature of 350 to 700 C.