Method for producing pressurelessly sintered zirconium diboride/silicon carbide composite bodies

Abstract

A method of sintering a ZrB 2 —SiC composite body at ambient pressures, including blending a first predetermined amount of ZrB 2 powder with a second predetermined amount of SiC powder, wherein both powders are characterized by the presence of surface oxide impurities. Next the blended powders are mixed to yield a substantially homogeneous powder mixture and a portion of the substantially homogeneous powder mixture is formed into a green body. The body is fired to a first temperature, wherein substantially all surface oxide impurities are reduced and/or volatilized to substantially eliminate oxides from the green body, and the body is heated to a second temperature and sintered to yield a composite body of at least about 99 percent theoretical density and characterized by SiC whisker-like inclusions distributed substantially evenly in a ZrB 2 matrix.

1 . A pressurelessly sintered ZrB 2  composite body, comprising from about 1 weight percent to about 25 weight percent SiC with the rest being substantially ZrB 2 , wherein the composite material is substantially free of oxide impurities and wherein SiC is present as a substantially uniformly distributed whisker-like phase in a ZrB 2  matrix. 
     
     
         2 . The pressurelessly sintered ZrB 2  composite body of  claim 1  wherein the body is about 99 percent theoretically dense. 
     
     
         3 . The pressurelessly sintered ZrB 2  composite body of  claim 1  wherein body has a porosity of no more than 1 percent. 
     
     
         4 . The pressurelessly sintered ZrB 2  composite body of  claim 1  wherein the SiC whiskers are generally between about 10 and about 20 μm in length. 
     
     
         5 - 27 . (canceled) 
     
     
         28 . The pressurelessly sintered ZrB 2  composite body of  claim 1  wherein body has a porosity of no more than 0.5 percent. 
     
     
         29 . The pressurelessly sintered ZrB 2  composite body of  claim 1  wherein the body is at least about 99.5 percent theoretically dense. 
     
     
         30 . A ZrB 2  composite body, comprising from about 75 weight percent to about 99 weight percent ZrB 2  with the rest being substantially SiC, wherein the composite material is substantially free of oxide impurities, wherein SiC is present as a distributed particulate phase in a ZrB 2  matrix, and wherein the composite body has a density greater than 99.5 percent theoretically dense. 
     
     
         31 . The ZrB 2  composite body of  claim 30  wherein the SiC phase particles are substantially acicular. 
     
     
         32 . The ZrB 2  composite body of  claim 30  wherein the SiC phase particles are substantially equiaxial. 
     
     
         32 . The ZrB 2  composite body of  claim 30  wherein the composite material is substantially free of oxide impurities. 
     
     
         33 . A refractory body, comprising a composite material defining a first ZrB 2  matrix phase and a second dispersed phase of SiC, wherein the ZrB 2  matrix phase is present in between about 75 weight percent to about 99 weight percent of the composite material with the rest being SiC, wherein the composite material is substantially free of oxides, wherein the SiC phase is present as a distributed particulate phase in the ZrB 2  matrix, and wherein the composite body has a density greater than 99.5 percent of theoretical density.