Boron Aluminum Magnesium Coating for Earth-Boring Bit

Abstract

A rotatable cone earth boring bit has a bearing system with at least on the surfaces being AlMgB14 alloy material. The alloy material also contains an alloying agent, which may be titanium boride (TiB2); titanium carbide (TiC) plus iron, nickel and carbon; silicon nitride (Si3N4) powder; whiskered silicon nitride (Si3N4); boron carbide (B4C); titanium boride (TiB2); or tungsten boride (W2B4). The surface containing the AlMgB14 alloy material may be a journal surface or thrust face on the bearing pin. The surface containing the AlMgB14 alloy material may also be a seal surface, either on a metal face seal or a gland on the bearing pin engaged by an elastomeric ring. The AlMgB14 alloy material may a coating or it may be a free-standing structural member within the bearing system.

1 . A downhole well tool having at least one rotatable member, a bearing system including a bearing member having bearing surfaces on which the rotatable member rotates and a seal having a seal surface in sliding engagement with a mating seal surface to retain lubricant within the bearing system, the improvement comprising:
 at least one of the surfaces comprising an AlMgB14 alloy material.   
     
     
         2 . The well tool according to  claim 1 , wherein the alloy material further comprises a dopant selected from a group consisting of: titanium boride (TiB2); titanium carbide (TiC) plus iron, nickel and carbon; silicon nitride (Si3N4) powder; whiskered silicon nitride (Si3N4); boron carbide (B4C); titanium boride (TiB2); and tungsten boride (W2B4). 
     
     
         3 . The well tool according to  claim 2 , wherein the dopant creates a phase within the alloy material that has a grain size less than 100 nanometers. 
     
     
         4 . The well tool according to  claim 2 , wherein the whiskered silicon nitride comprise fibers having diameters less than 100 nanometers. 
     
     
         5 . The well tool according to  claim 1 , wherein the AlMgB14 alloy material comprises a coating on said at least one of the surfaces. 
     
     
         6 . The well tool according to  claim 1 , wherein the AlMgB14 alloy material comprises a free-standing structure bonded to said at least one of the surfaces. 
     
     
         7 . The well tool according to  claim 1 , wherein said at least one of the surfaces is at least one of the bearing surfaces and which comprises:
 a cylindrical journal surface on the bearing member.   
     
     
         8 . The well tool according to  claim 1 , wherein said at least one of the surface is at least one of the bearing surfaces and which comprises:
 a fiat circular thrust face on the bearing member.   
     
     
         9 . The well tool according to  claim 1 , wherein said at least one of the surface is at least one of the bearing surfaces and which comprises:
 cylindrical surfaces of roller bearings.   
     
     
         10 . The well tool according to  claim 1 , wherein said at least one of the surfaces is at least one of the seal surfaces and which comprises a seal face of a rigid face seal assembly. 
     
     
         11 . The well tool according to  claim 1 , wherein said at least one of the surface is the mating seal surface and which comprises an annular seal gland on the bearing member that is slidingly engaged by an elastomeric seal ring. 
     
     
         12 . An earth boring bit, comprising:
 at least one rotatable cone with external cutting elements;   a bearing system comprising:   a bearing pin having bearing surfaces on which the cone rotates;   a seal having a seal surface in sliding engagement with a mating seal surface to retain lubricant within the bearing system;   at least one of the surfaces comprising an AlMgB14 alloy material; and   
       the AlMgB14 bearing material having an alloying agent selected from a group consisting of: titanium boride (TiB2); titanium carbide (TiC) plus iron, nickel and carbon; silicon nitride (Si3N4) powder; whiskered silicon nitride (Si3N4); boron carbide (B4C); titanium boride (TiB2); and tungsten boride (W2B4). 
     
     
         13 . The bit according to  claim 12 , wherein said at least one of the surfaces is at least one of the bearing surfaces and which comprises:
 an exterior surface of a bearing ring stationarily mounted on the bearing pin and defining a bearing journal.   
     
     
         14 . The bit according to  claim 12 , wherein said at least one of the surface is at least one of the bearing surfaces and which comprises:
 a flat circular disk stationarily mounted on a thrust face of the bearing pin.   
     
     
         15 . The bit according to  claim 12 , wherein said at least one of the surface is at least one of the bearing surfaces and which comprises:
 cylindrical surfaces of roller bearings.   
     
     
         16 . The bit according to  claim 12 , wherein said at least one of the surfaces is at least one of the seal surfaces and which comprises a rigid seal face of a rigid face seal assembly. 
     
     
         17 . The bit according to  claim 12 , wherein said at least one of the surface is the mating seal surface and which comprises a sleeve mounted around the bearing pin and slidingly engaged by an elastomeric seal ring. 
     
     
         18 . The bit according to  claim 12 , wherein the AlMgB14 alloy material comprises a coating on said at least one of the surfaces. 
     
     
         19 . The bit according to  claim 12 , wherein the AlMgB14 alloy material comprises a free-standing structure bonded to said at least one of the surfaces. 
     
     
         20 . An earth boring bit, comprising:
 at least one rotatable cone with external cutting elements, the cone having a cavity with a bearing surface;   a bearing pin having a bearing surfaces on which the bearing surface of the cone rotates;   at least one of the bearing surfaces comprising an AlMgB14 alloy coating; and   
       the AlMgB14 bearing coating having an alloying agent selected from a group consisting of: titanium boride (TiB2); titanium carbide (TiC) plus iron, nickel and carbon; silicon nitride (Si3N4) powder; whiskered silicon nitride (Si3N4); boron carbide (B4C); titanium boride (TiB2); and tungsten boride (W2B4). 
     
     
         21 . The bit according to  claim 20 , wherein:
 the bearing surface of the bearing pin comprises an exterior surface of a bearing ring stationarily mounted on the bearing pin and defining a bearing journal; and   the coating is located on the exterior surface of the bearing ring.