Shin-etsu Chemical Co., Ltd.

Takao Maeda

Toshihiko Tsukatani

Hajime Nakano

Yasushi Takai

Noriaki Hamaya

Masaru Konya

Kazuhiro Wataya

Satoshi Shima

Hirofumi Kawazoe

Junichi Nakayama

Masami Kaneyoshi

Naofumi Shinya

Yuuichi Makino

Ichiro Uehara

Yuko Shima, Legal Representative

A powder comprising rare earth element fluoride particles having an aspect ratio of up to 2, an average particle size of 10-100 &#x3bc;m, a bulk density of 0.8-1.5 g/cm, and a carbon content of 0.1-0.5 wt % is amenable to atmospheric plasma spraying. An article obtained by spraying the rare earth fluoride spray powder to a substrate undergoes few partial color changes and performs well even when used in a halogen gas plasma.

Rare earth fluoride spray powder and rare earth fluoride-sprayed article

A wafer has a rare earth oxide layer disposed, typically sprayed, on a substrate. It is useful as a dummy wafer in a plasma etching or deposition system.

Wafer

A corrosion resistant member to be exposed to a halogen-containing gas atmosphere or a halogen-containing gas plasma atmosphere, comprising a substrate and a plurality of layers deposited thereon including a layer of rare earth fluoride providing the outermost surface and a layer of rare earth oxide having a porosity of less than 5% underlying the rare earth fluoride layer.

Corrosion resistant multilayer member

A wafer has a rare earth fluoride coating disposed, typically sprayed on a substrate as an outermost layer, the rare earth fluoride being selected from lanthanoid fluorides, yttrium fluoride, and scandium fluoride. It is useful as a dummy wafer in a plasma etching or deposition system.

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.

Rare earth metal member and making method

An electrically conductive, plasma-resistant member adapted for exposure to a halogen-based gas plasma atmosphere includes a substrate having formed on at least part of a region thereof to be exposed to the plasma a thermal spray coating composed of yttrium metal or yttrium metal in admixture with yttrium oxide and/or yttrium fluoride so as to confer electrical conductivity. Because the member is conductive and has an improved erosion resistance to halogen-based corrosive gases or plasmas thereof, particle contamination due to plasma etching when used in semiconductor manufacturing equipment or flat panel display manufacturing equipment can be suppressed.

Conductive, plasma-resistant member

A Group IIIA element fluoride-containing coating comprising a Group IIIA element fluoride phase which contains at least 50% of a crystalline phase of the orthorhombic system belonging to space group Pnma is formed on a member for imparting corrosion resistance so that the member may be used in a corrosive halogen species-containing atmosphere. When the state of a crystalline phase is properly controlled, the coating experiences only a little color change by corrosion. A Group IIIA element fluoride-containing coating having a micro-Vickers hardness Hv of at least 100 is minimized in weight loss by-corrosion.

Fluoride-containing coating and coated member

An electrostatic chuck is provided in which a lower oxide coating, an electrode, and an upper oxide coating are formed on a substrate. The lower oxide coating is formed by spraying an oxide of Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu and has a dielectric strength of 15-50 kV/mm.

Electrostatic chuck

Spherical particles of a rare earth (inclusive of yttrium)-containing compound and having a breaking strength of 10-300 MPa and an average particle diameter of 10-80 &#x3bc;m are suitable for plasma spraying.

Thermal spray spherical particles, and sprayed components

A rare-earth oxide thermal spray coated article comprising a substrate and a coating layer formed by thermally spraying a rare-earth oxide thermal spraying powder onto a surface of the substrate, said coating layer being of a gray or black color having, in the L*a*b* color space, an L* value of up to 50, an a value of &#x2212;3.0 to +3.0, and a b* value of &#x2212;3.0 to +3.0.

Rare-earth oxide thermal spray coated articles and powders for thermal spraying

Rare earth oxide particles having an average particle diameter of 3-20 &mgr;m, a dispersion index of up to 0.4, and an aspect ratio of up to 2 are suitable for thermal spraying. Despite their high melting point, the rare earth oxide particles of high purity can form an adherent coating by thermal spraying.

Thermal spray rare earth oxide particles, sprayed components, and corrosion resistant components

An object of the present invention is to provide a hydrogen absorbing alloy which can improve a high rate discharge property while suppressing particle size reduction, exhibits cycle life characteristics equal to or higher than those of conventional alloys even when its cobalt content is decreased, and has a high capacity. Specifically, the present invention provides a hydrogen absorbing alloy having a CaCu type crystal structure in its principal phase, wherein the La content in the alloy is in the range of 24 to 33% by weight and the Mg or Ca content in the alloy is in the range of 0.1 to 1.0% by weight, as well as the aforesaid alloy wherein the Co content in the alloy is not greater than 9% by weight.

Hydrogen absorbing alloy and nickel-metal hydride rechargeable battery

The invention discloses an efficient method for the formation of a highly corrosion- or etching-resistant thermal spray coating layer of a rare earth oxide or rare earth-based composite oxide by a process of plasma thermal spray method by using a unique thermal spray powder consisting of granules of the oxide. The thermal spray granules are characterized by a specified average particle diameter of 5 to 80 &mgr;m with a specified dispersion index of 0.1 to 0.7 and a specified BET specific surface area of 1 to 5 m /g as well as a very low content of impurity iron not exceeding 5 ppm by weight as oxide. The flame spat powder used here is characterized by several other granulometric parameters including globular particle configuration, particle diameter D , bulk density and cumulative pore volume.

Method for thermal spray coating and rare earth oxide powder used therefor

The invention discloses a material and an efficient method for the formation of a thermal-spray coating layer of a rare earth fluoride by a process of thermal-spray coating by using a unique thermal spray powder consisting of granules of the rare earth fluoride having a specified average particle diameter. The thermal-spray granules are prepared by granulating primary particles of the rare earth fluoride having a specified average particle diameter from an aqueous slurry containing a binder resin and subjecting the granules to a calcination treatment at a temperature not higher than 600&deg; C.

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Takefu, Japan

Takao Maeda