Corrosion-resistant silicon nitride ceramics
US7510785B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 15, 2005 |
| Grant date | Mar 31, 2009 |
| Priority date | — |
| Expiry date | May 19, 2027 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF05D2300/2283
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A corrosion-resistant silicon nitride ceramics in which an adhesion enhancing layer (3), a stress relaxing layer (4) and a crack extension preventing layer (5) are laminated in this order on a ceramic substrate (2) composed mainly of silicon nitride, and a surface corrosion-resistant layer (6) composed mainly of zirconium oxide stabilized by an element of the group 3a of the periodic table is laminated. The thermal expansion coefficient (α0) of the ceramic substrate (2), the thermal expansion coefficient(α1) of the adhesion enhancing layer (3), and the thermal expansion coefficient (α2) of the stress relaxing layer (4), the thermal expansion coefficient (α3) of the crack extension preventing layer (5), and the thermal expansion coefficient (α4) of the surface corrosion-resistant layer (6) satisfy the following relational expressions (I) to (III):α0≈α1 (I)α3<α2 (II)α3<α4 (III).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.