Ceramics with high toughness, strength and hardness
US5002911A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1989 |
| Grant date | Mar 26, 1991 |
| Priority date | — |
| Expiry date | Apr 7, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2235/96
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A ceramic comprising a matrix of Al.sub.2 O.sub.3, ZrO.sub.2 (partially or fully stabilized) or mixtures of Al.sub.2 O.sub.3 and ZrO.sub.2 with strontium aluminate plate-shaped grains distributed throughout the matrix results in a ceramic with high toughness, high strength and good hardness. SrO/Al.sub.2 O.sub.3 molar ratios between 0.02 and 0.20 result in in-situ formation of plate-shaped grains approximately 0.5 .mu.m in thickness and 5.0 .mu.m in breadth in tetragonal zirconia polycrystalline ceramic matrices. The in-situ formation of strontium aluminates allows high volume loading of platelets to occur and high toughness is achieved without the loss of strength. High alumina compositions have the added benefit of higher strength, lower thermal expansion, higher modulus and higher thermal conductivity than zirconia ceramics with comparable toughness.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.