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US 8,298,333 B2Granted
Crucible for the crystallization of silicon and process for making the same
AssigneeVesuvius Crucible Company
InventorGilbert Rancoule
Life of this patent
Estimating the term…
Abstract
A protective coating is prepared for, and applied to, crucibles used in the handling of molten materials that are solidified in the crucible and then removed as ingots. Crucibles containing this protective coating may be used for the solidification of silicon. The coating has a specified oxygen content and contains a mineral binder and silicon nitride or silicon oxynitride.
Claims16
A crucible for the crystallization of silicon comprising:
- a) a base body comprising a bottom surface and side walls defining an inner volume;
- b) a silicon nitride based protective coating facing the inner volume;
- wherein said protective coating comprises from 80 to 95 wt. % of silicon nitride and from 5 to 20 wt. % of a low temperature mineral binder, and a total oxygen content from 5 to 15% by weight.
Process for the preparation of a crucible for the crystallization of silicon comprising the steps of:
- a) providing a base body comprising a bottom surface and side walls defining an inner volume;
- and
- b) applying a protective coating comprising 80 to 95 wt. % of silicon nitride and 5 to 20 wt. % of a low temperature mineral binder, wherein the total oxygen content is higher than 5% by weight at the surface of the side walls facing the inner volume.
Dependencies are inferred from the claim text.