RARE EARTH ELEMENT OXYFLOURIDE POWDER SPRAY MATERIAL AND SPRAYED ARTICLE
A spray material comprising rare earth element oxyfluoride particles having an aspect ratio of up to 2, an average particle size of 10-100 μm, and a bulk density of 0.8-2 g/cm 3 , and containing not more than 0.5 wt % of carbon and 3-15 wt % of oxygen is suitable for air plasma spraying. An article having a sprayed coating of rare earth element oxyfluoride has high resistance against plasma etching and a long lifetime.
1 . A spray material comprising rare earth element oxyfluoride particles having an aspect ratio of up to 2, an average particle size of 10 to 100 μm, and a bulk density of 0.8 to 2 g/cm 3 , and containing not more than 0.5% by weight of carbon and 3 to 15% by weight of oxygen.
2 . The spray material of claim 1 wherein the rare earth element is one or more elements selected from the group consisting of Y and Group 3A elements from La to Lu.
3 . The spray material of claim 2 wherein the rare earth element is selected from the group consisting of Y, Gd and Er.
4 . The spray material of claim 1 which is obtained by mixing 10 to 70% by weight of rare earth element oxide having an average particle size of 0.01 to 5 μm and the balance of rare earth element fluoride having an average particle size of 0.1 to 5 μm, agglomerating, and firing.
5 . A rare earth element oxyfluoride-sprayed article comprising a substrate and a sprayed coating which is deposited on the substrate by plasma spraying the spray material of any one of claims 1 to 4 , the sprayed coating having a carbon content of not more than 0.1% by weight and an oxygen content of 3 to 15% by weight.