Damage caused by cavitation and erosion is observed on hydro-turbines, pumps, pipes, gates, draft tubes, and outlet conduits. Mitigating the effects of this degradation on metallic hydraulic steel structures will reduce downtime and costly repairs. Traditionally, stainless steel weld overlays are used for cavitation repairs on these structures. Welding stainless to mild steel creates a galvanic corrosion cell in immersion conditions, which can cause delamination of the stainless steel and subsequent loss of cavitation protection. Cavitation resistant coatings could be used in combination with stainless steel weld overlays to eliminate the galvanic corrosion cell, thus providing protection and extending the service life of the repairs. This paper investigates the cavitation resistance and material properties of polymeric elastomer coatings. Several elastomers were selected for testing based on their mechanical properties such as percent elongation, tensile strength, tear resistance, and Shore hardness. Findings include the results of laboratory testing of cavitation resistant coatings. Elastomers are shown to provide better cavitation and erosion resistance than ceramic filled epoxies.

Subject
Cavitation, Test methods, Zinc rich coatings, Materials, Erosion resistance, Polyurethanes, Epoxy coatings, Polyurethane coatings, Erosion, Steel, Elastomers, Stainless steel, Damage
Keywords:
cavitation, coatings, erosion, corrosion
Government work published by the Association for Materials Protection and Performance (AMPP) with permission of the author(s). Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2023
GOV
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