Rare earth metal member and making method
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsToshihiko Tsukatani, Hajime Nakano, Takao Maeda
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Abstract
By using a rare earth metal having a minimal content of impurity metal element, machining it into a member and cleaning with an organic acid-base capping agent, there is obtained a rare earth metal member composed entirely of a rare earth metal and containing not more than 100 ppm of impurity metal element in a sub-surface zone, which member is characterized by a high surface purity, a large grain size, minimized grain boundaries, and improved halogen resistance or corrosion resistance.
Claims11
A polycrystalline rare earth metal member consisting essentially of a rare earth metal and having an outermost surface, said member containing not more than 100 ppm of at least one metal element selected from the group consisting of Na, K, Ca, Mg, Fe, Cr, Cu, Ni, Zn and Al in a zone extending from the outermost surface to a depth of 2 μm,
- wherein the polycrystalline rare earth metal member comprises grains having a grain size of at least 3 mm.
Dependencies are inferred from the claim text.