Overview

The Basics of Erosion Corrosion

Erosion corrosion is a form of surface deterioration that occurs when the combined action of mechanical erosion and electrochemical corrosion leads to accelerated material loss and surface damage. This failure mode is commonly observed in systems exposed to aggressive and high-velocity fluid environments, such as pipes, pump impellers, and heat exchangers. The appearance of this metal failure mode is characterized by waves, grooves, valleys, and rounded holes that typically exhibit a directional pattern.

Erosion corrosion can be defined as the accelerated loss of material or alteration of surface morphology due to the synergistic action of mechanical erosion and electrochemical corrosion in the presence of a moving corrosive fluid. Some terms may be used interchangeably to describe the metal failure, such as flow-assisted corrosion, impingement corrosion, and combined corrosion-erosion.

Several factors influence the rapid progression of erosion corrosion in industrial applications. Some variables include:

Fluid Properties: The velocity, turbulence, particle content, and chemical composition of the fluid medium can affect the rate of mechanical erosion and electrochemical corrosion, influencing the extent of the metal failure mode.
Environment: The temperature, humidity, and presence of aggressive chemicals in the environment can impact the rate of electrochemical corrosion, affecting the speed of progression and severity of the metal failure mode.
Material Surface: The presence and stability of protective surface films, such as oxide layers, can affect the corrosion rate and the material’s overall resistance to corrosion and erosion.
Mechanical Stress: The presence of mechanical stress on the material can exacerbate this metal failure mode by promoting crack initiation and propagation, which in turn accelerates material degradation.

To minimize the occurrence and severity of the metal failure mode, employ a few strategies, such as:

Proper Fluid Management: Control fluid velocity, turbulence, and particle content to reduce mechanical erosion and slow the rate of the failure mode.
Surface Modification: Use functional coatings specifically engineered for harsh environments to improve the surface hardness, corrosion resistance, and wear resistance of the components, making them less susceptible to the rapid progression of the metal failure mode.
Preventative Maintenance: Establish a preventive maintenance program to regularly monitor and maintain the system, including cleaning, inspecting, and replacing worn components to avoid conditions that can lead to the metal failure mode taking over your systems.

Armoloy's Solution to Metal Failure

Armoloy offers multiple metal surface treatments with varying levels of protection from the common causes of metal failure modes. Offering both broad-spectrum and industry-specific applications, our protective metallic coatings add significant value through increased performance and decreased revenue losses from unplanned maintenance and downtime.

Our protective coatings ensure a thin, precise coat that won’t impact production, but will improve surface hardness and prevent environmental defects. Beyond increasing wear life, Armoloy tailors our metallic coatings based on the specific requirements of your application and industry.

The combined effects of erosion and corrosion presents a significant challenge for engineers in various mechanical systems exposed to aggressive and high-velocity fluid environments, and the failure mode progresses quite rapidly once identified. By understanding its key variables and implementing proactive mitigation steps, this metal failure mode can be effectively minimized from causing detrimental impact to industrial applications. Read Diagnosing Erosive vs. Corrosive Metal Failure for more details on metal failure modes.

Beyond the Lab: Metal Failures in Narrative Form

Other Metal Failure Modes

Other common metal failures include:

This metal failure can also result from, or be a precursor to, other potential metal failures

Eliminate metal failure from your operations. Meet our group of curious, innovative engineers and learn how we can help improve your industry with science-based solutions.

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Erosion-Corrosion