Nickel based wear and corrosion protected shank adapter

Abstract

A shank adapter forming part of a drilling assembly includes a longitudinal axis, an external surface, an internal surface, a threaded part provided at a forward end and a plurality of splines provided at a rearward end. A machine part extends axially between the threaded part and the splines, wherein at least a part of the external surface is coated with a first corrosion protection layer of nickel and at least part of the first corrosion protection layer is coated with a polymer based sealant top layer.

1 . A shank adapter arranged to form part of a drilling assembly, the shank adapter comprising:
 a longitudinal axis;   an external surface;   an internal surface;   a threaded part provided at a forward end and a plurality of splines provided at a rearward end; and   a machine part extending axially between the threaded part and the plurality of splines, wherein at least part of the external surface is coated with a first corrosion protection layer comprising nickel, and wherein at least part of the first corrosion protection layer is coated with a polymer based sealant top layer.   
     
     
         2 . The shank adapter according to  claim 1 , wherein additionally at least part of the internal surface is coated with the first corrosion protection layer and/or the polymer based sealant top layer. 
     
     
         3 . The shank adapter according to  claim 1 , wherein a thickness of the first corrosion protection layer is between 5-200 μm. 
     
     
         4 . The shank adapter according to  any of the previous claim 1 , wherein a thickness of the polymer based sealant top layer is between 0.5-10 μm. 
     
     
         5 . The shank adapter according to  claim 1 , wherein the first corrosion protection layer is a nickel phosphorous alloy. 
     
     
         6 . The shank adapter according to  claim 5 , wherein the phosphorus content of the nickel phosphorus alloy is 6-9 wt %. 
     
     
         7 . The shank adapter according to  any of the previous claim 1 , wherein the polymer based sealant top layer comprises is a polymer having a friction coefficient of between 0.05-0.15. 
     
     
         8 . The shank adapter according to  any of the previous claim 1 , wherein the first corrosion protection layer and the polymer based sealant top layer are located on the machine part. 
     
     
         9 . The shank adapter according to  any of the previous claim 1 , wherein the first corrosion protection layer and the polymer based sealant top layer are located on all parts of the shank adapter. 
     
     
         10 . The shank adapter according any of claims to  claim 1 , wherein the rearward end of the shank adapter is uncoated. 
     
     
         11 . A method for providing corrosion protection on a shank adapter according to any of  claim 1 , the method comprising the steps of:
 depositing a first corrosion protection layer comprising including nickel on at least part of the external surface of the shank adapter;   depositing a polymer based sealant top layer on top of the first corrosion protection layer; and   heat treating the coated shank adapter.   
     
     
         12 . The method according to  claim 11 , wherein the first corrosion protection layer is applied using an electroless nickel bath. 
     
     
         13 . The method according to  claim 11 , wherein the polymer based sealant top layer is sprayed on. 
     
     
         14 . The method according to  claim 11 , wherein the heat treating is conducted at a temperature of between 150-300° C. for 30-120 minutes. 
     
     
         15 . The method according to  claim 11 , wherein the external surface of the shank adapter is shot peened or blasted before the nickel based corrosion protection layer is applied.