The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 21, 2014
Filed:
Jul. 09, 2007
Yoshiaki Hirose, Mitoyo, JP;
Tetsuya Yuki, Mitoyo, JP;
Yoshiaki Hirose, Mitoyo, JP;
Tetsuya Yuki, Mitoyo, JP;
Toyo Tanso Co., Ltd., Osaka-shi, JP;
Abstract
A crucible protection sheet is provided that can prevent damages to an inner crucible, hinder an outer crucible from silicon-carbidization, and transmit heat from the outer crucible to the inner crucible uniformly. In a crucible having an inner crucibleand an outer crucible, the crucible protection sheet is arranged between the two crucibles and is made of expanded graphite. The planar thermal conductivity is 120 W/(m·K) or higher, the gas permeability is less than 1.0×10cm/s, and the compression ratio is 20% or higher when the sheet is compressed in a thickness direction at a pressure of 34.3 MPa. Since the compression ratio is high, the effect of preventing breakage is great when inserting the inner crucible, improving workability and preventing the inner crucible from tilting inside the outer crucible. In addition, even though the compression ratio is high, the thermal conductivity is kept to such a degree that the inner crucible can be heated uniformly, and the gas shielding capability is also ensured. As a result, the outer crucible is prevented from silicon-carbidization and thickness decrease.