Causes of Corrosion
Corrosion is the deterioration of a material, typically a metal, due to its reaction with its environment. There are several main culprits behind this breakdown:
- Electrochemical Reactions: This is the most common cause. When a metal comes into contact with a corrosive electrolyte (like salt water), an electrical current is generated. This current causes the metal to dissolve at the anode (positively charged) and new compounds to form at the cathode (negatively charged).
- Gases and Chemicals: Exposure to aggressive gases like oxygen, sulfur dioxide, or chlorine can directly attack the metal surface, forming oxides, sulfides, or chlorides.
- Stress: Mechanical stress on a metal can exacerbate corrosion, especially in corrosive environments. Cracks and imperfections can act as starting points for further deterioration.
- Stray Currents: Leakage currents from electrical systems can accelerate corrosion on nearby metallic components.
Overcoming Corrosion with Thermal Spray
Thermal spraying is a powerful technique for combating corrosion. It involves melting a coating material (usually metal, ceramic, or a composite) and spraying it at high velocity onto the surface of a substrate. This creates a new, corrosion-resistant barrier that protects the underlying material.
Here’s how thermal spraying overcomes corrosion:
- Barrier Effect: The coating acts as a physical barrier, isolating the substrate from the corrosive environment.
- Sacrificial Protection: Some coatings, like zinc, are more susceptible to corrosion than the substrate. They corrode first, protecting the substrate beneath.
- Improved Resistance: Coatings can be chosen for their inherent resistance to specific corrosive agents. For example, aluminum coatings can resist oxidation at high temperatures.
- Rehabilitation: Thermal spraying can be used to restore corroded components, extending their service life.
Thermal spraying offers a versatile and cost-effective solution for corrosion control across various industries, including
- Aerospace
- Power Generation
- Oil and Gas
- Steel
- Pump
- Valve
- Air & Gas Compressor
- Hydraulic
- Plastic
- Boiler