Protective Coatings

Protective Coatings for Corrosion Control

Protective coatings for corrosion control

The industrial, commercial, and architectural markets rely heavily on coatings for the protection of assets. In a general sense, coatings are defined as a thin layer of solid material on a surface that provides improved protective, decorative, or functional properties. More specifically, they are a liquid, liquefiable, or mastic composition that, after application to a surface, is converted into a solid protective, decorative, or functional adherent film. Protective coatings are applied to a surface to protect the substrate from corrosion. An effective way in which to protect metal from corrosion is by physical isolating a substrate from its environment by applying protective coatings.

Coatings protect against corrosion through one of the following ways: they block necessary elements from coming to together to start the corrosion process, actively prevent the electrochemical reaction from occurring, or steer the corrosion process in a direction that is will not harm the asset.

Quick Facts

Types of coating protection include: 

  • Barrier -- Protect by preventing water, oxygen, and electrolytes from contact with an underlying metal
  • Inhibitive -- Coatings that contain chemicals that work to hinder corrosion
  • Sacrificial -- Thin metal layers that have lower electrode potential values or those having higher levels in the electrochemical series are applied
  • Combination

Materials typically used in protective coatings are:

  • polymers, epoxies, and polyurethanes for non-metallic coatings
  • zinc, aluminum, and chromium for metallic coatings 

Application

Coatings, which includes paints, can be:

  • sprayed
  • welded
  • plated, or
  • applied with hand tools (specific to the surface, environment, and application goals)

The process for applying protective coatings involves:

  • surface preparation
  • application of a primer
  • a full coating
  • use of a sealant

For information specific to “Coatings Inspection” see section titled Measurement and Inspection

Standards

NACE/SSPC Joint Surface Preparation Standards Package (NACE No 1, 2, 3, 4, 5, 6, 8)

Paint and Coatings Selection

Paint Application

ANSI/NACE No. 13/SSPC-ASC-1-2016, Industrial Coating and Lining Application Specialist Qualification and Certification

SP0108, Corrosion Control of Offshore Structures by Protective Coatings

SP0892-2007-SG (formerly RP0892), Coatings and Linings over Concrete for Chemical Immersion and Containment Service

SP0490-2007 (formerly RP0490), Holiday Detection of Fusion-Bonded Epoxy External Pipeline Coating of 250 to 760 µm (10 to 30 mil)

TM0104-2004, Offshore Platform Ballast Water Tank Coating System Evaluation

NACE No. 6/SSPC-SP 13-2018, Surface Preparation of Concrete

Metallic and Ceramic Thermal Spray Coatings For Oil and Gas Production Equipment

Standards Development Committees

AMPP SC 02 External Coatings - Atmospheric
Develops and maintains standards, guides, and reports for coatings utilized in environments exposed to the atmosphere.

AMPP SC 03 External Coatings - Buried & Immersed
Develops and maintains standards, guides, and reports for external coatings of materials, equipment, and structures in direct contact with salt water, fresh water, or soil environments.

AMPP SC 04Linings & Internal Coatings
Develops and maintains standards, guides and reports for linings and internal coatings commonly used in specialized internal environments such as steel tanks, pipelines, and vessels to protect from corrosion and/or chemical attack.

AMPP SC 05 Surface Preparation
Develops and maintains standards, guides, and reports for preparing surfaces in order to increase adhesion to coatings and linings.

AMPP SC 12 Concrete Infrastructure
Develops and maintains standards, guides, and reports to disseminate information on the effectiveness of various corrosion protection systems for construction and rehabilitation of reinforced concrete infrastructure, and on the methodology for the evaluation of reinforced and pre-stressed structures.

AMPP SC 23 Coating System Application, Maintenance, and Inspection
Develops and maintains standards, guides, and reports related to coating application, maintenance, and inspection processes and procedures.

Also, AMPP Technical Communities of Interest - Surface Preparation, Atmospheric Coatings, Concrete, Immersion & Buried Service, and Linings (Coatings Technical Subcommittee)