A forming method of an yttrium oxide fluoride (YOF) coating film and a (YOF) coating film formed thereby are disclosed. The YOF coating film has no or extremely small pores therein and a nanostructure to increase light transmittance thereof, and has high hardness and high bonding strength and thus can protect a transparent window of a display device. The method for forming an YOF coating film involves the steps of: providing pretreated YOF powder having a particle diameter ranging from 0.1 to 12 μm; receiving a transfer gas supplied from a transfer gas supply unit and receiving the pretreated YOF powder supplied from a powder supply unit to transfer the pretreated YOF powder in an aerosol state; and colliding/smashing (spraying) the pretreated YOF powder transferred in the aerosol state with/onto a substrate in a process chamber to form an YOF coating film on the substrate.

A method for extracting and separating rare earth elements comprising providing a rare earth-containing ore or tailings, grinding the rare earth-containing ore to form powdered ore; leaching the powered ore with at least one mineral acid, forming a leach solution comprising at least one metal ion, rare earth elements and a solid material, separating the solid material from the leach solution to form aqueous-metal concentrate, precipitating the aqueous-metal concentrate to selectively remove the metal ion from the leach solution and obtain a precipitate of the rare earth elements; heating the precipitate of the rare earth elements in air to form oxide of the rare earth elements, mixing the oxide of the rare earth elements with an ammonium salt and heating in a dry air/nitrogen, forming a mixture of anhydrous rare earth salts in an aqueous solution, and separating the rare earth elements from the aqueous solution by means of an electrowinning process.

A genus of rare earth containing chemicals is disclosed. These rare earth containing chemicals are suitable for use in sequential vapor deposition processes to form rare earth fluoride or rare earth oxyfluoride films. Such films may be used to protect materials and devices from corrosive chemicals.

A genus of rare earth containing chemicals is disclosed. These rare earth containing chemicals are suitable for use in sequential vapor deposition processes to form rare earth fluoride or rare earth oxyfluoride films. Such films may be used to protect materials and devices from corrosive chemicals.

A sintered body, a method of fabricating the sintered body, a semiconductor fabricating device, and a method of fabricating the semiconductor fabricating device, the sintered body including 50 mass % or more of Y.sub.5O.sub.4F.sub.7, wherein the sintered body has a relative density of 97.0% or more and a Vickers hardness of 2.4 GPa or more.

A sintered body, a method of fabricating the sintered body, a semiconductor fabricating device, and a method of fabricating the semiconductor fabricating device, the sintered body including 50 mass % or more of Y.sub.5O.sub.4F.sub.7, wherein the sintered body has a relative density of 97.0% or more and a Vickers hardness of 2.4 GPa or more.

An inorganic compound for a Li-ion conductor includes an oxyhalide compound with a chemical composition of MOX where M is at least one of Al, Sc, La, and Y, and X is at least one of F, Cl, Br, and I. Also, the oxyhalide compound has a thermal decomposition start temperature of the oxyhalide compound is greater than a thermal decomposition start temperature of FeOCl and a conductivity that is general equal to or greater than a conductivity of the FeOCl.

An inorganic compound for a Li-ion conductor includes an oxyhalide compound with a chemical composition of MOX where M is at least one of Al, Sc, La, and Y, and X is at least one of F, Cl, Br, and I. Also, the oxyhalide compound has a thermal decomposition start temperature of the oxyhalide compound is greater than a thermal decomposition start temperature of FeOCl and a conductivity that is general equal to or greater than a conductivity of the FeOCl.

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.