Hard coating film and method for forming the same

Abstract

A hard coating film to be applied to the surface of a tool, which has a composition of (Cr 1-a-b Al a Si b ) (B x C y N 1-x-y ) with atomic ratios specified below. 0<a≦0.4 0.05≦b≦0.35 0.25≦1−a−b≦0.9 0≦x≦0.15 0≦y≦0.5 or a composition of (M 1-a-b Al a Si b ) (B x C y N 1-x-y ) with atomic ratios specified below. 0.05≦a≦0.5 0.1<b≦0.35 0≦x≦0.15 0≦y≦0.5 where M denotes Ti and Cr. The hard coating film for cutting tools has better wear resistance than conventional ones.

What is claimed is: 
     
       1. A hard coating film to be applied to the surface of a tool, wherein the hard coating film has comprising at least one first layer having a composition of (Cr 1-a-b Al a Si b ) (B x C y N 1-x-y ), where a, b, x and y are atomic ratios and
   0<a≦0.4,   0.05≦b≦0.35,   0.25≦1−a−b≦0.9,   0.03≦x≦0.15, and   0≦y≦0.5; and   
 the hard coating film has the a crystal structure of rock salt and does not include an amorphous phase. 
 
     
     
       2. A hard coating film to be applied to the surface of a tool, wherein the hard coating film comprises a single comprising at least one first layer having a composition of (M 1-a-b Al a Si b ) (B x C y N 1-x-y ), where a, b, x and y are atomic ratios and
   0.05≦a≦0.3,   0.1<b≦0.35,   0≦x≦0.15,   0≦y≦0.5,   M denotes the presence of both Ti and Cr, and   an atomic ratio of Ti in (M 1-a-b Al a Si b ) is in a range of from 0.03 to 0.43.   
 
     
     
       3. The hard coating film defined in  claim 1 , which contains wherein the at least one first layer comprises oxygen. 
     
     
       4. The hard coating film defined in  claim 2 , which contains wherein the at least one first layer comprises oxygen. 
     
     
       5. The hard coating film defined in  claim 3 , which has the wherein the at least one first layer comprises a moiety of (B x C y N 1-x-y-z O z ), where
 0.03≦x≦0.15, 
 0≦y≦0.5, 
 0<z≦0.5, and 
 0.35≦1−x−y−z<1. 
 
     
     
       6. The hard coating film defined in  claim 4 , which has the wherein the at least one first layer comprises a moiety of (B x C y N 1-x-y O z ) (B x C y N 1-x-y-z O z ), where
 0≦x≦0.15, 
 0≦y≦0.5, 
 0<z≦0.5, and 
 0.35≦1−x−y−z<1. 
 
     
     
       7. The hard coating film defined in  claim 1 , which wherein the at least one first layer comprises two or more first layers differing in composition within the specified range. 
     
     
       8. The hard coating film defined in  claim 2 , which wherein the at least one first layer comprises two or more first layers differing in composition within the specified range. 
     
     
       9. The hard coating film defined in  claim 3 , which wherein the at least one first layer comprises two or more first layers differing in composition within the specified range. 
     
     
       10. The hard coating film defined in  claim 4 , which wherein the at least one first layer comprises two or more first layers differing in composition within the specified range. 
     
     
       11. The hard coating film defined in  claim 1 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       12. The hard coating film defined in  claim 2 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       13. The hard coating film defined in  claim 3 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       14. The hard coating film defined in  claim 4 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       15. The hard coating film defined in  claim 5 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       16. The hard coating film defined in  claim 6 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       17. The hard coating film defined in  claim 7 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       18. The hard coating film defined in  claim 8 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       19. The hard coating film defined in  claim 9 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       20. The hard coating film defined in  claim 10 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being formed from comprising any of nitride, carbide, boride, carbonitride, carboboride, boronitride, and carboboronitride of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si, with their a composition differing from that the composition of the at least one first layer of the hard coating film defined above. 
     
     
       21. The hard coating film defined in  claim 1 , which has further comprising an additional at least one second layer on one side or both sides thereof of the at least one first layer, the additional at least one second layer being a metal layer or an alloy layer containing comprising at least one species of a metal selected from the group consisting of Groups  4 A,  5 A, and  6 A, Al, and Si. 
     
     
       22. The hard coating film defined in  claim 11 , which has wherein the at least one second layer comprises two or more additional second layers. 
     
     
       23. The hard coating film defined in  claim 21 , which has wherein the at least one second layer comprises two or more additional second layers. 
     
     
       24. A method for forming a hard coating film, the method comprising coating on a work the hard coating film defined in  claim 1  by an unbalanced magnetron sputtering method or a cathodic arc ion plating method that employs a mechanism to apply a magnetic field. 
     
     
       25. A method for forming a hard coating film, the method comprising coating on a work the hard coating film defined in  claim 21  by an unbalanced magnetron sputtering method or a cathodic arc ion plating method that employs a mechanism to apply a magnetic field. 
     
     
       26. The method defined in  claim 24 , the method further comprising generating a line of magnetic force which is approximately normal to a target's an evaporating surface of a target and is parallel or extends slightly outward with respect to a perpendicular line of the target's evaporating surface of the target, the magnetic force readily converting a film-forming gas into plasma in a neighborhood of the work being coated. 
     
     
       27. The method defined in  claim 25 , the method further comprising generating a line of magnetic force which is approximately normal to a target's an evaporating surface of a target and is parallel or extends slightly outward with respect to a perpendicular line of the target's evaporating surface of the target, the magnetic force readily converting a film-forming gas into plasma in a neighborhood of the work being coated. 
     
     
       28. A hard coating film to be applied to the surface of a tool, wherein the hard coating film has comprising at least one layer having a composition of (M 1-a-b Al a Si b ) (B x C y N 1-x-y ), where a, b, x and y are atomic ratios and
   0.05≦a≦0.5,   0.1<b≦0.35,   0.035≦x≦0.15,   0≦y≦0.5, and   M denotes Ti and Cr; and   
 the hard coating film has the a crystal structure of rock salt and does not include an amorphous phase. 
 
     
     
       29. A hard coating film to be applied to the surface of a tool, wherein the hard coating film comprises comprising at least one first layer and at least one second layer laminated alternatively; alternately, wherein 
 the first layer has a composition including Ti, Cr, Al and N; and 
 the second layer has a composition of (M 1-a-b Al a Si b ) (B x C y N 1-x-y ), where a, b, x and y are atomic ratios and
 0.05≦a≦0.3, 
 0.1<b≦0.35, 
 0≦x≦0.15, 
 0≦y≦0.5, 
 M denotes Ti and Cr, and 
 
 an atomic ratio of Ti in (M 1-a-b Al a Si b ) is in a range of from 0.03 to 0.43. 
 
     
     
       30. A hard coating film comprising at least one first layer and at least one second layer laminated alternately, wherein
 the first layer has a composition including Ti, Cr, Al and N; and   the second layer has a composition of (M 1-a-b Al a Si b ) (B x C y N 1-x-y ), where a, b, x and y are atomic ratios and   0.05≦a≦0.5,   0.1<b≦0.35,   0≦x≦0.15,   0≦y≦0.5,   M denotes Ti and Cr, and   an atomic ratio of Ti in (M 1-a-b Al a Si b ) is in a range of from 0.03 to 0.43.