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Electroless Ni-P and Ni-P composite Coating on Stainless Steel Sand Screens

IP.com Disclosure Number: IPCOM000249834D
Publication Date: 2017-Apr-12
Document File: 3 page(s) / 15K

Publishing Venue

The IP.com Prior Art Database

Abstract

Screens used for sand control in Oil and Gas industry are typically made up of corrosion resistant alloys; primarily stainless steel (304 or 316 L) and for sour environments Inconel or other nickel alloys are recommended. Erosive wear caused by the impingement of sand on the surface of the sand control equipment is a primary reason for failure of such equipment. Thus, a protective coating is beneficial to extend the lifetime of the tools. The invention proposed here describes a method for enabling an electroless Ni or Ni alloy composite coating to be deposited on stainless steel work pieces (as well as other alloys that have a native strong oxide layer) without sacrifice of the adhesion. The area of application envisioned here comprise completions equipment for the downhole environment, and with the main purpose of improving erosion resistance. Electroless Ni coatings have been successfully used in a number of industrial applications to improve the resistance to corrosion and to wear. Deposition of these coatings rely on the auto-catalytic reduction of Nin+ solutions on an electrical conductive surface capable of providing electrons to the reaction. For many industrially relevant metals and alloys and on parts of simple geometries and small dimensions, a good chemical wash or pickling treatment suffices to create a surface that is conducive to electroless deposition. This however is not the case for Stainless Steels or Aluminum alloys where a very dense and resilient passive layer forms when immersed in aqueous solution or exposed to air. In addition to inhibiting the auto-catalytic deposition reaction, presence of the oxide layer severely hinders the adhesion between the work piece and the coating. Screens used for sand control in Oil and Gas industry are typically made up of corrosion resistant alloys; primarily stainless steel (304 or 316 L) and for sour environments Inconel or other nickel alloys are recommended. Erosive wear caused by the impingement of sand on the surface of the sand control equipment is a primary reason for failure of such equipment. Thus, a protective coating is beneficial to extend the lifetime of the tools. The invention proposed here describes a method for enabling an electroless Ni or Ni alloy composite coating to be deposited on stainless steel work pieces (as well as other alloys that have a native strong oxide layer) without sacrifice of the adhesion. The area of application envisioned here comprise completions equipment for the downhole environment, and with the main purpose of improving erosion resistance. Detailed Description of method: As indicated previously the main challenge encountered in the plating of electroless Ni-P or Ni-B or Ni alloy onto stainless steel is the presence of a strongly adherent oxide layer formed primarily of chromium oxide. This imparts a dielectric nature to the surface that prevents the auto-catalytic reaction of Ni plating from taking place. Two methods are proposed here to achieve this deposition. The first one is good for the case when line-of-sight process is acceptable, and the second one is suitable for the case were non-line-of-sight coatings are required. The method #1 proposed here for the fabrication of said coatings comprise of the following steps: 1. Degreasing of surface with detergent solution & rinsing with distilled water 2. Surface cleaning with an acid solution (HNO3 & HCl) to dissolve the native chromium oxide protective layer 3. Electroplating of a thin Ni layer on the cleaned surface to a thickness of 1 to 10 um 4. Rapid thermal annealing to promote partial inter-diffusion between the electro-deposited Ni and the SS workpiece. The duration of this heat treatment is short (of the order of a few seconds), so that only the surface of the workpiece is heated, and there is no alteration of the alloy of the workpiece 5. Electroless deposition of Ni-P or Ni-P composites till final desired thickness The method #2 propsed here for the fabrication of said coatings comprise the following steps: 1. Degreasing of surface with detergent solution & rinsing with distilled water 2. Surface cleaning with an acid solution (e.g. HNO3 & HCl) to dissolve the native chromium oxide protective layer 3. Surface activation with PdCl2 & HCl 4. Treating in NaH2PO2 5. Rapid thermal annealing to promote partial inter-diffusion between Pd and Fe (Optional). The duration of this heat treatment is short (of the order of a few seconds), so that only the surface of the work piece is heated, and there is no alteration of the alloy of the work piece 6. Electroless deposition of Ni-P or Ni-P composites till final desired thickness.

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Electroless Ni-P and Ni-P composite Coating on Stainless Steel Sand Screens

Screens used for sand control in Oil and Gas industry are typically made up of corrosion resistant alloys; primarily stainless steel (304 or 316 L) and for sour environments Inconel or other nickel alloys are recommended. Erosive wear caused by the  impingement of sand on the surface of the sand control equipment is a primary reason for failure of such equipment. Thus, a protective coating is beneficial to extend the lifetime of the tools. The invention proposed here describes a method for enabling an electroless Ni or Ni alloy composite coating to be

deposited on stainless steel work pieces (as well as other alloys that have a native strong oxide layer) without sacrifice of the adhesion. The area of application envisioned here comprise completions equipment for the downhole environment, and with the main purpose of improving erosion resistance.

Electroless Ni coatings have been successfully used in a number of industrial applications to improve the resistance to corrosion and to wear. Deposition of these coatings rely on the auto-catalytic reduction of Nin+ solutions on an electrical conductive surface capable of providing electrons to the reaction. For many industrially relevant metals and alloys and on parts of simple geometries and small dimensions, a good chemical wash or pickling treatment suffices to create a surface that is conducive to electroless deposition. This however is not the case for Stainless Steels or Aluminum alloys where a very dense and resilient passive layer forms when immersed in aqueous solution or exposed to air. In addition to inhibiting the auto-catalytic deposition reaction, presence of the oxide layer severely

hinders the adhesion between the work piece and the coating. Screens used for sand control in Oil and Gas industry are typically made up of corrosion resistant alloys; primarily stainless steel (304 or 316 L) and for sour environments Inconel or other nickel alloys are recommended. Erosive wear caused by the impingement of sand on the surface of the sand control equipment is a primary reason for failure of such equipment. Thus, a protective coating is beneficial to extend the lifetime of the tools. The invention proposed here describes

a method for enabling an electroless Ni or Ni alloy composite coating to be deposited on stainless steel work pieces (as well as other alloys that...