초록 ▼

The invention provides composite materials comprising eucryptite particles distributed in a matrix material other than eucryptite. The matrix material may be a ceramic material such as an oxide ceramic. In an embodiment, the eucryptite particles are transformed from the β-phase to the ε-

The invention provides composite materials comprising eucryptite particles distributed in a matrix material other than eucryptite. The matrix material may be a ceramic material such as an oxide ceramic. In an embodiment, the eucryptite particles are transformed from the β-phase to the ε-phase during fabrication of the composite. This phase transformation can enable a eucryptite-based transformation toughening mechanism.

대표청구항 ▼

We claim: 1. A ceramic composite material consisting essentially of: a. a crystalline ceramic matrix material having a porosity less than 10%, the ceramic material being other than eucryptite; and b. eucryptite particles dispersed in the matrix material, the particles having a size between 0.1 and

We claim: 1. A ceramic composite material consisting essentially of: a. a crystalline ceramic matrix material having a porosity less than 10%, the ceramic material being other than eucryptite; and b. eucryptite particles dispersed in the matrix material, the particles having a size between 0.1 and 10 microns and the volume fraction of the particles being between 5 and 20 volume percent, wherein at least some of the eucryptite particles are ε-eucryptite particles wherein the ceramic composite material is made by forming a mixture comprising particles of β-eucryptite and particles of the non-eucryptite ceramic material, sintering the mixture to form a precursor composite material having β-eucryptite particles dispersed in the non-eucryptite ceramic matrix material, and cooling the precursor composite material, the non-eucryptite ceramic material being selected so that the cooling process leads to compressive stresses in the vicinity of the β-eucryptite particles sufficient to transform at least some of the β-eucryptite particles to ε-eucryptite particles. 2. The composite material of claim 1, wherein the matrix material is zirconia. 3. The composite material of claim 1, wherein the size of the eucryptite particles is between 1 micron and 10 microns. 4. The composite material of claim 1, wherein the matrix material is titania. 5. The composite material of claim 1, wherein the ceramic matrix is not significantly microcracked. 6. The composite material of claim 1, wherein the porosity of the ceramic matrix is less than 5%. 7. A ceramic composite material consisting essentially of: a. a crystalline matrix material selected from the group consisting of alumina and zirconia, the matrix material having a porosity less than 5%, and b. eucryptite particles dispersed in the matrix material, the particles having a size between 0.1 and 10 microns and the volume fraction of the particles being between 5 and 20 volume percent, wherein at least some of the eucryptite particles are ε-eucryptite particles wherein the ceramic composite material is made by forming a mixture comprising particles of β-eucryptite and particles of alumina or zirconia, sintering the mixture to form a precursor composite material having β-eucryptite particles dispersed in the alumina or zirconia matrix material, and cooling the precursor composite material such that the cooling process leads to compressive stresses in the vicinity of the β-eucryptite particles sufficient to transform at least some of the β-eucryptite particles to ε-eucryptite particles. 8. The composite material of claim 7, wherein the eucryptite particles are between 1 microns and 10 microns. 9. The composite material of claim 7, wherein the matrix material is alumina. 10. The composite material of claim 7, wherein the matrix material is not significantly microcracked. 11. The composite material of claim 7, wherein the matrix material is zirconia. 12. The composite material of claim 1, wherein the matrix material is magnesia. 13. The composite material of claim 1, wherein the matrix material is alumina.