Super-abrasive grain and super-abrasive grinding wheel

Abstract

There is provided a super-abrasive grain including: a body composed of cubic boron nitride or diamond; and a ceramic coating film coating at least a portion of a surface of the body.

1 . A super-abrasive grain comprising:
 a body composed of cubic boron nitride or diamond; and   a ceramic coating film coating at least a portion of a surface of the body.   
     
     
         2 . The super-abrasive grain according to  claim 1 , wherein the body has a single-crystal structure. 
     
     
         3 . The super-abrasive grain according to  claim 1 , wherein the body has a polycrystalline structure. 
     
     
         4 . The super-abrasive grain according to  claim 1 , wherein the coating film has an average crystal grain size of 500 nm or less. 
     
     
         5 . The super-abrasive grain according to  claim 4 , wherein the coating film has an average crystal grain size of 50 nm or less. 
     
     
         6 . The super-abrasive grain according to  claim 1 , wherein the coating film contains one selected from the following (a) and (b):
 (a) a nitride, a carbide, a carbonitride, an oxide, or an oxynitride containing one or more elements selected from group 4 elements, group 5 elements and group 6 elements in the periodic table, Al, Si, Y, Mg, and Ca; and   (b) diamond-like carbon or diamond.   
     
     
         7 . The super-abrasive grain according to  claim 1 , wherein the coating film is composed of (Ti 1-xb1-yb1 Si xb1 M1 yb1 ) (C 1-zb1 N zb1 ), or (Al 1-xb2 M2 xb2 ) (C 1-zb2 N zb2 ), where
 M1=one or more elements selected from group 4 elements, group 5 elements and group 6 elements in the periodic table, and Al (Note that Ti is excluded),   xb1=0 or more and 0.45 or less,   yb1=0 or more and 0.5 or less,   zb1=0.2 or more and 0.5 or less, and   M2=one or more elements selected from group 4 elements, group 5 elements and group 6 elements in the periodic table, and Si,   xb2=0.025 or more and 0.475 or less,   zb2=0.2 or more and 0.5 or less.   
     
     
         8 . The super-abrasive grain according to  claim 1 , wherein the coating film has a thickness of 1 nm or more and 5000 nm or less. 
     
     
         9 . The super-abrasive grain according to  claim 1 , wherein the coating film has a multilayer structure composed of a plurality of stacked ceramic layers. 
     
     
         10 . The super-abrasive grain according to  claim 1 , further comprising an insulating film covering an outer surface of the coating film. 
     
     
         11 . The super-abrasive grain according to  claim 10 , wherein the insulating film includes a compound of any one of an oxide and an oxynitride containing one or more elements selected from Al, Si, Zr, and Ti. 
     
     
         12 . The super-abrasive grain according  claim 10 , wherein the insulating film has a thickness of 1 nm or more and 5000 nm or less. 
     
     
         13 . The super-abrasive grain according to  claim 1 , wherein the body has a grain size of 1 μm or more and 600 μm or less. 
     
     
         14 . A super-abrasive grinding wheel comprising:
 a disk-shaped substrate; and   a super-abrasive grain layer covering at least an outer peripheral surface of the substrate,   the super-abrasive grain layer having the super-abrasive grain according to  claim 1 .