Cutting elements and bits incorporating the same

Abstract

Cutting elements and bits incorporating such cutting elements are provided. The cutting elements have a substrate, a first ultra hard material layer formed over the substrate, and a second ultra hard material layer formed over the first ultra hard material layer. The second ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm.

1 . A cutting element comprising:
 a substrate;   a first ultra hard material layer formed over the substrate; and   a second ultra hard material layer formed over the first ultra hard material layer, wherein the second ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm, wherein both layers comprise PCD.   
   
   
       2 . A cutting element as recited in  claim 1  wherein the second ultra hard material layer has a higher abrasion resistance than an first ultra hard material layer. 
   
   
       3 . A cutting element as recited in  claim 1  wherein the second ultra hard material layer comprises an average ultra hard material particle size that is smaller than an average ultra hard material particle size of the first ultra hard material layer. 
   
   
       4 . A cutting element as recited in  claim 1  wherein the second ultra hard material layer is a TSP material layer. 
   
   
       5 . A cutting element as recited in  claim 1  wherein the second ultra hard material layer encapsulates the first ultra hard material layer. 
   
   
       6 . A cutting element as recited in  claim 1  wherein the second ultra hard material layer is formed over only a portion of the first ultra hard material layer. 
   
   
       7 . A cutting element as recited in  claim 1  wherein the first ultra hard material layer has an upper surface and a peripheral surface having a height and wherein the second ultra hard material layer covers between 50% to 100% of the height of the peripheral surface. 
   
   
       8 . A cutting element as recited in  claim 1  wherein the thickness of the second ultra hard material layer is not constant. 
   
   
       9 . A cutting element as recited in  claim 1  wherein a surface of the second ultra hard material layer interfacing with the first ultra hard material layer is non-uniform. 
   
   
       10 . A cutting element as recited in  claim 1  wherein the first and second ultra hard material layers comprise the same type of ultra hard material. 
   
   
       11 . A cutting element as recited in  claim 1  wherein the first and second ultra hard material layers are different types of ultra hard material layers. 
   
   
       12 . A cutting element as recited in  claim 1  wherein the first ultra hard material layer comprises a non-uniform outer surface. 
   
   
       13 . A cutting element as recited in  claim 1  wherein the first ultra hard material layer comprises a depression and wherein the second ultra hard material layer is within the depression. 
   
   
       14 . A cutting element as recited in  claim 1  further comprising a third ultra hard material layer formed over the first ultra hard material layer and spaced apart from the second ultra hard material layer, wherein the third ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm. 
   
   
       15 . A cutting element as recited in  claim 1  wherein the second ultra hard material layer defines a cutting edge of the cutting element to be used for cutting. 
   
   
       16 . A cutting element as recited in  claim 1  wherein when the second ultra hard material layer wears it forms a scar exposing the first ultra hard material layer and said second ultra hard material layer defines at least a lip having a sharp edge surrounding said scar, wherein the first ultra hard material layer wears faster than the second ultra hard material layer. 
   
   
       17 . A bit comprising a body and a cutting element as recited in  claim 1  mounted on said body. 
   
   
       18 . A bit comprising:
 a body; and   a cutting element mounted on the body, the cutting element comprising,
 a substrate, and 
 a cutting layer formed over the substrate, the cutting layer comprising,
 a first ultra hard material layer formed over the substrate, and 
 a second ultra hard material layer formed over the first ultra hard material layer, wherein the second ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm, wherein both layers comprise PCD, and wherein said second ultra hard material layer is oriented for making contact with an object to be drilled by said bit. 
 
   
   
   
       19 . A drill bit as recited in  claim 18  wherein the cutting element cutting layer further comprises a third ultra hard material layer formed over the first ultra hard material layer and spaced apart from the second ultra hard material layer, wherein the third ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm. 
   
   
       20 . A drill bit as recited in  claim 18  wherein the second ultra hard material layer covers the entire first ultra hard material layer.