Protective Coating Options
Many down hole applications are in non-standard environments, where abrasion, corrosion or erosion characteristics might be present. Three of the most common options for protecting oilfield tools from these environments are: BorFusion™, Polymer Coatings or Electroless Nickel Plating.
Each of these options have their advantages.
Boronizing, processes such as BorFusion™: (Abrasion, Corrosion, Erosion Resistant)
The BorFusion™ process creates a bond between the material substrate and the boron agent, this chemical reaction changes the composition on the surface of the steel resulting in an extremely hard surface layer. The benefits to BorFusion™ are highlighted when dealing with any amount of solids, corrosive gasses and/or erosive environments.
- The boronized surface has a hardness reading between 76 – 80+ Rockwell C.
- Hardened layer is EXTREMELY resistant to solids varying from sand production to dissolved solids.
- The boronized layer is diffused into the substrate, not sprayed on, providing resistance to erosive scale environments as well as gassy applications such as CO2 or H2S.
- Case thickness is approximately 4 -6 thou thick, with only 20% surface growth, allowing parts with tight tolerances to stay in spec.
Polymer Coating: (Corrosion Resistant, Non-Stick)
Polymer coatings’ main advantages are corrosion resistance in water injection, water producing and chloride or disposal wells and for its non-stick/high release properties. The spray-on application of polymer coatings is cured into a rubber like material providing excellent resistance against H2S, Chlorides, and scale build up. Due to its relatively soft layer, polymer coatings are not recommended in highly abrasive applications.
- Polymer coatings are typically applied at a thickness between .0008" to .0015"
- The coated layer is entirely built up on top of the original substrate, it is not diffused into the substrate.
- The polymer PTFE binder is very durable against corrosive gasses.
- Recommended in chloride applications and water injection/producing and disposal wells.
- Non-stick properties allow for high release of scale and protection against galling.
Electroless Nickel Coating (ENC): (Corrosion Resistant)
High phosphorous Electroless Nickel offers maximum resistance in strongly acidic corrosive environments – ENC is most commonly used to protect against CO2 gasses and CO2 Injection wells in the Oil & Gas Industry. The auto-catalytic reaction causes the nickel coating to deposit onto the substrate, creating a uniform coating throughout the entire tool. With a plated hardness of 45 Rockwell C, along with great adhesion to the substrate, EN plating also offers better wear resistant properties than Polymer Coatings.
- Withstands over 1000hrs of salt spray exposure test with no rust (Excellent corrosion resistance).
- Uniform plating procedure, even on complex parts.
- Very low porosity in deposits provides an excellent barrier for corrosion protection.
- Recommended in highly acidic corrosive environments
- Great protection against CO2.