Yttrium-based sprayed coating and making method
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsYasushi Takai, Noriaki Hamaya
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Abstract
An yttrium-base sprayed coating is obtained by thermally spraying yttrium oxide, yttrium fluoride or yttrium oxyfluoride onto a substrate to form a coating of 10-500 μm thick, and chemically cleaning the coating with a cleaning liquid of organic acid, inorganic acid or a mixture thereof until the population of particles with a size of up to 300 nm becomes no more than 5 particles/mm2 of the coating surface. The yttrium-base sprayed coating exhibits high corrosion resistance even in a halogen gas plasma atmosphere and prevents yttrium-base particles from spalling off during etching treatment.
Claims4
A method for preparing a yttrium-base sprayed coating, comprising the steps of:
- thermally spraying a spray material comprising particles of one or two or more selected from the group consisting of yttrium oxide, yttrium fluoride and yttrium oxyfluoride onto a substrate which is readily dissolved in acid so as to form a yttrium-base sprayed coating having a thickness of 10 to 500 μm on the substrate, and
- chemically cleaning a surface of the yttrium-base sprayed coating with a cleaning liquid composed of an organic acid aqueous solution so as to reduce a number of particles with a size of up to 300 nm which exist on the surface of the coating to not more than 5 particles per square millimeters, wherein
- the organic acid aqueous solution is an aqueous solution of at least one selected from the group consisting of a monofunctional carboxylic acid, a difunctional carboxylic acid, a trifunctional carboxylic acid and a hydroxy acid, or an aqueous solution of a mixture of at least two thereof.
Dependencies are inferred from the claim text.