Toughness enhanced silicon-containing composite bodies, and methods for making same
US6995103B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 15, 2002 |
| Grant date | Feb 7, 2006 |
| Priority date | — |
| Expiry date | Oct 15, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2237/365
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A silicon-containing composite body that would otherwise be brittle can be engineered to exhibit enhanced fracture toughness. Specifically, a silicon-ceramic composite body is produced, preferably by a reactive infiltration technique. The ceramic is selected such that it has a higher coefficient of thermal expansion (CTE) than does the silicon phase. At least at some point during processing, the silicon phase is at a temperature above its normal ductile/brittle transition temperature of about 500° C., and preferably above its melting point. The formed composite body containing the silicon phase is then cooled below its ductile/brittle transition. During cooling, the ceramic phase shrinks more than does the silicon phase, thereby placing the latter in a state of compressive stress. By the time the composite body has cooled to substantially ambient temperature, the induced compressive stress in the silicon phase is sufficient as to impart a measurable degree of semi-ductile character to the silicon phase. This pseudo-ductility manifests itself in the composite body as a significant increase in the fracture toughness of the body. For example, when the ceramic reinforcement was boron c…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.