초록 ▼

Pressureless sintering of silicon carbide with fracture toughness in excess of about 4 MPa-m1/2 as measured by the single-edge precracked beam (SEPB) technique while maintaining a density greater than 3.1 g/cc for compositions with SiC greater than about 94 wt. % is made possible through the use of

Pressureless sintering of silicon carbide with fracture toughness in excess of about 4 MPa-m1/2 as measured by the single-edge precracked beam (SEPB) technique while maintaining a density greater than 3.1 g/cc for compositions with SiC greater than about 94 wt. % is made possible through the use of metallic Al to promote sintering and grain growth. Boron and carbon may be used as traditional sintering aids, with nitrogen to suppress grain growth, and additions of yttrium and/or lanthanide elements to promote intergranular fracture.

대표청구항 ▼

What is claimed is: 1. A method of forming a sintered ceramic body comprising predominantly by weight silicon carbide, the method comprising the steps of:a) forming a green body from a mixture comprising the components:SiC;aluminum in elemental form;a rare earth metal in elemental or combined form;b

What is claimed is: 1. A method of forming a sintered ceramic body comprising predominantly by weight silicon carbide, the method comprising the steps of:a) forming a green body from a mixture comprising the components:SiC;aluminum in elemental form;a rare earth metal in elemental or combined form;boron in elemental or combined form; andnitrogen; andb) heating the green body under conditions resulting in a sintered ceramic body comprising at least 94 wt. % SiC, having a density above about 3.1 g/cc, and exhibiting an intergranular fracture mechanism.