Patent ID: 11964329
Assignee: TUNGALOY CORPORATION
Field: Surface technology, coating (Chemistry)
Classification: CPC B  C | IPC B  C

Claim 0:
1. A coated cutting tool comprising:
a substrate and a coating layer formed on a surface of the substrate, wherein
the coating layer includes a lower layer and an upper layer in this order from the substrate side toward a surface side of the coating layer,
the lower layer includes one or two or more Ti compound layers composed of a Ti compound of Ti and an element of at least one kind selected from the group consisting of C, N and O,
the upper layer includes an a type α-Al2O3 layer composed of α-Al2O3,
an average thickness of the lower layer is 2.0 μm or more and 15.0 μm or less,
an average thickness of the upper layer is 3.5 μm or more and 15.0 μm or less,
in the upper layer, a ratio of a length of Σ3 grain boundaries to a total length of 100% of a total grain boundary is more than 50% and 80% or less, and a ratio of the length of Σ3 grain boundaries to a total length of 100% of coincidence site lattice (CSL) grain boundaries is 70% or more, and
in the upper layer,
a texture coefficient TC(0,0,12) of a (0,0,12) plane of the a type α-Al2O3 layer represented by a following formula (1) is 8.0 or more and 8.9 or less:, TC
      ⁡
      (
      
       0
       ,
       0
       ,
       12
      
      )
     
     =
     
      
       
        I
        ⁡
        (
        
         0
         ,
         0
         ,
         12
        
        )
       
       
        
         I
         0
        
        (
        
         0
         ,
         0
         ,
         12
        
        )
       
      
      ⁢
      
       
        {
        
         
          1
          9
         
         ⁢
         
          ∑
          
           
            I
            ⁡
            (
            
             h
             ,
             k
             ,
             l
            
            )
           
           
            
             I
             0
            
            (
            
             h
             ,
             k
             ,
             l
            
            )
           
          
         
        
        }
       
       
        -
        1
       
      
     
    
   
   
    
     (
     1
     )
    
   
  
 

(in the formula (1), I(h,k,l) is a peak intensity obtained by X-ray diffraction measured on an (h,k,l) plane of the a type α-Al2O3 layer, I0(h,k,l) is a standard diffraction intensity of the (h,k,l) plane of α-Al2O3 according to JCPDS card number 10-0173, and (h,k,l) represents nine crystal planes: (0,1,2), (1,0,4), (1,1,3), (0,2,4), (1,1,6), (2,1,4), (3,0,0), (0,2,10), and (0,0,12)).