Cermets from molten metal infiltration processing
View Patent ↗New cermets with improved properties and applications are provided. These new cermets have lower density and/or higher hardness than B4C cermet. By incorporating other new ceramics into B4C powders or as a substitute for B4C, lower densities and/or higher hardness cermets result. The ceramic powders have much finer particle size than those previously used which significantly reduces grain size of the cermet microstructure and improves the cermet properties.
1. A cermet, comprising:
a porous ceramic preform matrix comprising ceramic powder that includes nano-powder size particles, wherein said ceramic powder comprises a blend of boron carbide, aluminum boride and magnesium boride, wherein said material comprises a density that is greater than 55%; and
metal alloy located in the pores of said porous ceramic perform matrix.
2. The cermet of claim 1 , wherein said nano-powder size particles comprise a particle size within a range from about 40 nm to about 900 nm.
3. The cermet of claim 1 , wherein said matrix comprises porosity within a range from about 20% to about 50%.
4. The cermet of claim 1 , wherein said ceramic powder comprises a nitride.
5. The cermet of claim 1 , wherein said alloy comprises a combination of elements selected from the group consisting of Al, Mg, Be, Li, Ti and V.
6. The cermet of claim 1 , wherein said alloy comprises a density of less than 2.8 gm/cc.
7. The cermet of claim 1 , wherein said size of each particle of said particles is about the same as that of all other said particles.
8. The cermet of claim 1 , wherein said alloy is able to wet said matrix at a temperature of less than 1150° C.
9. The cermet of claim 1 , wherein said alloy is able to wet said matrix at a temperature of less than 1150° C. within an infiltration period of less than 3 hours.
10. The cermet of claim 1 , wherein said matrix has been cold pressed to comprise said density that is greater than 55%.
11. The cermet of claim 1 , wherein said matrix is infiltrated with said metal alloy to greater than 98%.
12. The cermet of claim 1 , wherein said cermet has been heat treated to adjust the properties of said cermet for a specific application.
13. The cermet of claim 1 , wherein said ceramic powder blend has been pre-sintered to produce said density that is greater than 55%.