Some conventional maintenance solutions can be used to solve erosion-corrosion problems on pumps or to enhance pump efficiency. The solutions most commonly used for this problem are the selection of a different material for a pump and/or the application of various coating technologies.

Selection of the Material

The materials that are most commonly chosen, due to the cost, are conventional materials such as cast iron and stainless steel. However, the resistance of cast iron to corrosion and erosion is relatively low, which means this material is easily degradable; in the case of stainless steel, localised corrosion occurs when its protective passivation film is damaged. It also requires manpower and time to achieve a smooth metal finish.

Coating Technologies

Another way to reduce erosion-corrosion and to improve efficiency is to isolate the metal surface from its contact environment; a wide range of factory coating technologies can be applied, including glass flake coating, thermosetting polyurethane coating, modified solvented epoxy, and modified solvent-free epoxy; these have good corrosion protection properties. Nevertheless, these coating technologies possess some disadvantages, such as:

• Presence of VOC’s that might cause health and safety issues and it is shrinkage.
• Relatively poor adhesion and resistance to erosion, cavitations and impact compared to conventional solvent- free epoxy systems.
• Brittle and easily damaged during routine maintenance.
• Hi-build that forms flow restriction.
• Limited storage stability
• Low reactivity at low temperatures

A coating system with high erosion-corrosion resistance and which meets international health and safety standard is therefore required.