초록

A method for synthesizing low density cermets of boron carbide and a metal binder, using decomposition of a metallic compound at controlled temperature and pressure.

대표청구항 ▼

A method for preparation of boron carbide cermet material, the method comprising the steps of: providing boron carbide particles of representative diameter in the range 100 um or higher; providing particles of a predetermined metal hydride of a representative diameter no more than 10 um; mixing the

A method for preparation of boron carbide cermet material, the method comprising the steps of: providing boron carbide particles of representative diameter in the range 100 um or higher; providing particles of a predetermined metal hydride of a representative diameter no more than 10 um; mixing the boron carbide and metal hydride particles so that the metal hydride particles coat the surfaces of the boron carbide particles; placing the mixture in a metal container that is relatively inert with respect to chemical reactions with the metal hydride or with the boron carbide; providing an air-tight seal for the container; heating the container and mixture to a temperature T1 sufficient to decompose the metal hydride and release the hydrogen as a gas, and maintaining this temperature for a time period of at most 24 hours; imposing a vacuum of pressure at most 10-4 Torr on the contents of the heated container and removing the hydrogen gas from the container; increasing the temperature of the container contents to a predetermined temperature T2, which lies substantially between room temperature and 700°C., and imposing a predetermined static pressure p of substantially one kilobar or greater on the exterior walls of the container and maintaining this temperature and pressure for a time period of at least three hours, where this temperature and pressure are sufficient to deform the container walls and to cause the metal contained in the container to flow into and substantially fill all interstitial regions between adjacent boron carbide particles, and maintaining this temperature and pressure for at least one hour; lowering the temperature and pressure imposed on the container and its contents to room temperature and pressure, respectively; and removing the mixture of boron carbide and metal from the container.