Diamondlike carbon hard multilayer film formed body and method for producing the same

Abstract

A diamondlike carbon hard multilayer formed film body comprises a substrate, a diamondlike carbon film mainly composed of diamondlike carbon, and an intermediate layer between the substrate and the diamondlike carbon film. The diamondlike carbon film is composed of, in order from the substrate side, a first diamondlike carbon film and a second diamondlike carbon film. The surface hardness of the first diamondlike carbon film is within the range from not less than 10 GPa to not more than 40 GPa based on nanoindentation test, and the surface hardness of the second diamondlike carbon film is within the range from more than 40 GPa to not more than 90 GPa based on nanoindentation test. According to such a structure, even if a DLC multilayer containing high-hardness DLC film on the outermost surface side is formed in a thickness of not less than about 3 μm on a substrate of a wide range extending from a material with high hardness such as cemented carbide to an iron-based material with low hardness, excellent adhesion to both the substrate and the DLC film can be ensured in addition to excellent wear resistance.

1 . A diamondlike carbon hard multilayer film formed body, comprising: 
 a substrate;    a diamondlike carbon film mainly composed of diamond like carbon; and    an intermediate layer between said substrate and said diamondlike carbon film,    said diamondlike carbon film being composed of, in order from said substrate side, a first diamondlike carbon film and a second diamondlike carbon film,    the surface hardness of said first diamondlike carbon film being within the range from not less than 10 GPa to not more than 40 GPa based on nano indentation test, and    the surface hardness of said second diamondlike carbon film being within the range from more than 40 GPa to not more than 90 GPa based on nanoindentation test.    
     
     
         2 . The diamondlike carbon hard multilayer film formed body according to  claim 1 , wherein the surface hardness of said second diamondlike carbon film increases stepwise or continuously from the interface side between said first diamondlike carbon film and said second diamondlike carbon film toward the outermost layer side of said second diamondlike carbon film.  
     
     
         3 . The diamondlike carbon hard multilayer film formed body according to  claim 1 , wherein said substrate is composed of a cemented carbide material, and said intermediate layer is composed of, in order from said substrate side: 
 a first metal layer comprising at least one metal selected from the group consisting of W, Ta, Mo and Nb; and    an amorphous layer containing at least one metal selected from the group consisting of W, Ta, Mo and Nb, and C.    
     
     
         4 . The diamondlike carbon hard multilayer film formed body according to  claim 1 , wherein said substrate is composed of an iron-based substrate, and said intermediate layer is composed of, in order from said substrate side: 
 a second metal layer composed of at least one metal of Cr and Al;    a composite metal layer composed of at least one metal of Cr and Al and at least one metal selected from the group consisting of W, Ta, Mo and Nb;    a first metal layer composed of at least one metal selected from the group consisting of W, Ta, Mo and Nb; and    an amorphous layer containing at least one metal selected from the group consisting of W, Ta, Mo and Nb, and C.    
     
     
         5 . The diamondlike carbon hard multilayer film formed body according to  claim 1 , wherein the thickness of said intermediate layer is within the range from not less than 10% to not more than 50% relative to the total thickness of said diamondlike carbon hard multilayer film formed body, and the thickness of said second diamondlike carbon film is within the range from not less than 50% to not more than 90% relative to the total thickness of said diamondlike carbon hard multilayer film formed body except said intermediate layer.  
     
     
         6 . A method for producing a diamondlike carbon hard multilayer film formed body according to  claim 1 , comprising the steps of: 
 preparing a substrate;    forming an intermediate layer on said substrate by sputtering;    forming a first diamondlike carbon film on said intermediate layer by sputtering; and    forming a second diamondlike carbon film on said first diamondlike carbon film by cathode discharge type arc ion plating.    
     
     
         7 . The method for producing a diamondlike carbon hard multilayer film formed body according to  claim 6 , wherein a composite type coating device having a sputtering evaporation source and a cathode discharge type arc ion plating evaporation source provided within one vacuum chamber is used in the step of forming said intermediate layer by sputtering, the step of forming said first diamondlike carbon film by sputtering, and the step of forming said second diamondlike carbon film by cathode discharge type arc ion plating.  
     
     
         8 . The method for producing a diamondlike carbon hard multilayer film formed body according to  claim 6 , wherein the step of forming said intermediate layer by sputtering includes a forming process by unbalanced magnetron sputtering.  
     
     
         9 . The method for producing a diamondlike carbon hard multilayer film formed body according to  claim 6 , wherein the step of forming said first diamondlike carbon film by sputtering includes a forming process by unbalanced magnetron sputtering.  
     
     
         10 . The method for producing a diamondlike carbon hard multilayer film formed body according to  claim 7 , wherein said composite type coating device comprises an unbalanced magnetron type sputtering evaporation source.