Copper Thermal Spray Coating for Corrosion-Resistant Downhole Parts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermally sprayed alloys are not adequately resistant to corrosion in harsh downhole and marine environments, leading to equipment failure and production downtime due to corrosive substances like hydrogen sulfide, carbon dioxide, and biological growth.
Innovation Solution
A copper-based thermal spray alloy system with nickel, tin, boron, and carbon, which provides superior corrosion resistance and thermal conductivity, applied in thick deposits to downhole components and marine devices using a cored wire with a copper outer sheath, preventing micro-cracking and biological attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermally sprayed alloys are used, then wear resistance is improved, but corrosion resistance deteriorates in harsh downhole and marine environments
Solution Approach 1:
The patent applies composite materials by combining copper with nickel, tin, boron, and carbon in a cored wire configuration. The copper outer sheath provides corrosion resistance while the inner core contains nickel for wear resistance and boron/carbon for micro-crack prevention. This composite structure resolves the contradiction by integrating multiple materials with complementary properties into a single thermal spray coating system.
Solution Approach 2:
The patent changes the chemical composition parameters of the thermal spray alloy by specifying precise weight percentages: copper (50-90%), nickel (10-40%), tin (0-10%), boron (0-5%), and carbon (0-5%). This parameter optimization ensures the coating achieves both corrosion resistance from copper/nickel and wear resistance from the hardened microstructure created by boron and carbon, resolving the contradiction between these two properties.
2Strength
If thermal spray coatings are applied to downhole equipment, then wear conditions are mitigated, but equipment fails under corrosive conditions
Solution Approach 1:
The composite copper-nickel-tin-boron-carbon alloy creates a coating that simultaneously provides wear resistance and corrosion resistance, extending equipment service life in corrosive downhole environments. The copper matrix offers corrosion protection while nickel and tin enhance durability, and boron/carbon prevent micro-cracking that would otherwise limit service life.
Solution Approach 2:
The cored wire structure provides local quality by concentrating corrosion-resistant copper in the outer sheath that contacts the corrosive environment, while placing wear-resistant nickel and hardening boron/carbon in the inner core. This spatial distribution of properties optimizes both wear and corrosion resistance throughout the coating thickness, extending equipment life.
3Ease of manufacture
If conventional alloys are used, then manufacturing is simpler, but micro-cracking occurs reducing coating reliability
Solution Approach 1:
The patent changes the chemical composition by adding boron (0-5%) and carbon (0-5%) to the copper-nickel alloy. These elements modify the solidification behavior and microstructure of the thermal spray coating, preventing micro-crack formation during cooling. This compositional parameter change maintains coating integrity without complicating the thermal spray manufacturing process.
Solution Approach 2:
The composite alloy system with boron and carbon creates a more ductile and crack-resistant microstructure. The boron forms hard particles that reinforce the matrix while preventing crack propagation, and carbon provides similar benefits. This composite approach maintains coating reliability without requiring complex manufacturing procedures.
4Reliability
If copper-based alloy is used, then corrosion resistance and thermal conductivity are improved, but material cost increases
Solution Approach 1:
The patent optimizes the copper content to 50-90% and nickel to 10-40%, creating a cost-effective balance. The copper provides the primary corrosion resistance and thermal conductivity at lower cost, while nickel (10-40%) provides enhanced corrosion and wear resistance. This parameter range achieves superior performance without excessive material cost by avoiding high nickel content (>40%) or pure copper formulations.
Solution Approach 2:
The composite copper-nickel-tin-boron-carbon alloy distributes cost across multiple elements with complementary functions. Copper provides the base corrosion resistance and thermal conductivity, nickel enhances protection, and small amounts of tin, boron, and carbon provide specialized benefits. This composite approach achieves superior overall performance at moderate cost by leveraging the strengths of each element rather than relying on expensive single-element solutions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The copper-based alloy system significantly enhances corrosion resistance and thermal conductivity, preventing micro-cracking and biological growth, thus extending equipment life and reducing maintenance costs in corrosive environments.
Implementation Method 1
the term 'thermal spray' is a generic term for a group of processes in which metallic, ceramic, cermet, and some polymeric materials in the form of powder, wire, or rod are fed to a torch or gun with which they are heated to near or somewhat above their melting point. The resulting molten or nearly molten droplets of materials are projected against the surface to be coated.
Implementation Method 2
heated to near or somewhat above their melting point. The resulting molten or nearly molten droplets of materials are projected against the surface
Implementation Method 3
The copper-based alloy system significantly enhances corrosion resistance and thermal conductivity
Data Source
AI summary
The present disclosure provides a thermal spray alloy system that is more resistant to corrosion than conventional alloy compositions. The disclosed alloy comprises copper as the main component and also potentially nickel, tin, boron, and/or carbon as other principle elements. The alloy composition may utilize a cored wire, and an outer sheath of the cored wire may comprise unalloyed copper. The alloy has superior corrosion resistance to a wide number of corrosive materials, such as hydrogen sulfide, carbon dioxide/carbonic acid, sodium chloride/potassium chloride (salts), bio-fouling, and micro-biologicals. The alloy demonstrates superior thermal conductivity compared to nickel based alloys and stainless steels. The alloy may form an anti-corrosive coating that may be applied to any number of substrates. The disclosed alloy may be applied to a substrate in thick layers, such as between 0.100 inches and 3.0 inches, and may be used to form shapes, such as centralizers.