Composite bodies and methods of forming the same

Abstract

A composite body is provided that can include abrasive grains and at least one pore within a bond matrix, the abrasive grains including cubic boron nitride (cBN) and the bond matrix including a polycrystalline ceramic phase. The bonded abrasive may have a Modulus of Rupture (MOR) of not less than about 40 MPa. Certain embodiments may have porosity, such as, greater than about 5.0 vol %.

What is claimed is: 
     
         1 . A composite body comprising:
 a bond material comprising a ceramic material; and   a pore within the ceramic material;   wherein a region of the bond material at a surface of the pore defines a first pore defining composition distinct from a composition of the ceramic material, the first pore defining composition having a melting point not less than a melting point of the composition of the ceramic material.   
     
     
         2 . The composite body of  claim 1 , wherein the ceramic material comprises a material selected from the group consisting of an amorphous phase, a polycrystalline phase, and a combination thereof. 
     
     
         3 . The composite body of  claim 1 , wherein the first pore defining composition comprises a first crystalline content (C1) and the ceramic material comprises a second crystalline content (C2), wherein the first crystalline content is different than the second crystalline content 
     
     
         4 . The composite body of  claim 1 , wherein the first pore defining composition comprises a first amorphous content (A1) and the ceramic material comprises a second amorphous content (A2), wherein the first amorphous content is different than the second amorphous content. 
     
     
         5 . The composite body of  claim 1 , wherein a peripheral region of the bond material defined by at least a portion of a surface defining the opening and extending for a depth into the bond material has a first pore defining composition distinct from a composition of the ceramic material, the first pore defining composition having a melting point not less than a melting point of the composition of the ceramic material. 
     
     
         6 . The composite body of  claim 5 , wherein the depth is not greater than a diameter of the pore. 
     
     
         7 . The composite body of  claim 1 , wherein the first pore defining composition has a first hardness (H1) and the composition of the ceramic material has a second hardness (H2), and wherein first hardness is not less than the second hardness. 
     
     
         8 . The composite body of  claim 7 , wherein the first hardness is different from the second hardness by at least about 1% based on the equation [|(H1−H2)|/(0.5*(H1+H2))]*100%. 
     
     
         9 . The composite body of  claim 1 , wherein the first pore defining composition comprises a crystalline phase selected from the group consisting of cordierite, indialite, enstatite, sapphirine, anorthite, celsian, diopside, spinel, beta-spodumene, and a combination thereof. 
     
     
         10 . The composite body of  claim 1 , wherein the first pore defining composition is formed from a mixture comprising at least about 30 wt % and not greater than about 50 wt % silicon dioxide (SiO 2 ) for a total weight of the mixture. 
     
     
         11 . The composite body of  claim 1 , wherein the first pore defining composition is formed from a mixture comprising at least about 20 wt % and not greater than about 38 wt % aluminum oxide (Al 3 O 2 ) for a total weight of the mixture. 
     
     
         12 . A composite body comprising:
 a bond material comprising a ceramic material; and   a pore within the ceramic material;   wherein a region of the bond material at a surface of the pore defines a first pore defining composition distinct from a composition of the ceramic material;   wherein the first composition has a first hardness (H1) and the composition of the ceramic material has a second hardness (H2); and   wherein the first hardness is not less than the second hardness.   
     
     
         13 . The composite body of  claim 12 , wherein the first pore defining composition comprises a first crystalline content (C1) and the ceramic material comprises a second crystalline content (C2), wherein the first crystalline content is different than the second crystalline content 
     
     
         14 . The composite body of  claim 12 , wherein the first pore defining composition comprises a first amorphous content (A1) and the ceramic material comprises a second amorphous content (A2), wherein the first amorphous content is different than the second amorphous content. 
     
     
         15 . The composite body of  claim 12 , wherein the first pore defining composition comprises a crystalline phase selected from the group consisting of cordierite, indialite, enstatite, sapphirine, anorthite, celsian, diopside, spinel, beta-spodumene, and a combination thereof. 
     
     
         16 . The composite body of  claim 12 , wherein the first pore defining composition is formed from a mixture comprising at least about 30 wt % and not greater than about 50 wt % silicon dioxide (SiO 2 ) for a total weight of the mixture. 
     
     
         17 . The composite body of  claim 12 , wherein the first pore defining composition is formed from a mixture comprising at least about 20 wt % and not greater than about 38 wt % aluminum oxide (Al 3 O 2 ) for a total weight of the mixture. 
     
     
         18 . A method of forming a composite body comprising:
 providing a mixture comprising:
 a bond material precursor powder; and 
 a pore former comprising a first pore former composition; 
   forming the mixture into a composite body comprising a bond material including a ceramic material and a region surrounding a pore in the bond material,   wherein the ceramic material comprises a composition and the region surrounding the pore comprises a first pore defining composition, and   wherein the first pore defining composition has a melting point not less than a melting point of a composition of the ceramic material.   
     
     
         19 . The method of  claim 18 , wherein the wall has an average thickness of not greater than about 200 microns and at least about 1 micron. 
     
     
         20 . The method of  claim 18 , wherein the first pore former composition has a first hardness (H1) and the composition of the ceramic material has a second hardness (H2), and wherein first hardness is not less than the second hardness.