The operation of modern fluid machinery demands for low costs, reliability, longevity and no loss of fluid containment. All these can be achieved by minimising the material damage caused by the combined attack of solid particle or cavitation impingement and corrosion. This paper will cover the rationale behind the selection of erosion resistance surfaces for fluid machinery and highlight the complexities encountered when these surfaces are exposed to environments which contain sand particles or cavitation in a corrosive medium. The erosion and erosion-corrosion performance of a variety of coatings and bulk surfaces will be discussed using volume loss rate versus sand impact energy maps. The results show that polymeric coatings, in general, exhibited greater erosion rates than ceramic and metallic coatings. This difference in behaviour was probably accentuated by the jet angle selected (30 degree), since, for ductile materials (28), a maximum erosion rate occurs at oblique impact angles, whereas it is closer to 90 degree for brittle materials. Research into experimental HVOF aluminium bronze and aluminium alloys coatings shows synergy between erosion and corrosion processes on these passivating coatings is sensitive to sand loading, sand impact angle and sand energy. These coatings show good erosion-corrosion resistance at low impact energies with surface films formed by coating-electrolyte contact reducing the contact mechanics (or erosivity) of sand impingement. Although the performance of polymeric coatings can offer good erosion-corrosion resistance but their erosion resistance is not as good as carbon or stainless steel, however, bulk MDPE does offer improved resistance over steels and could be considered as a lining material for fluid machinery.
Challenges of living with erosion-corrosion
2004
20 Seiten, 12 Bilder, 5 Tabellen, 28 Quellen
Aufsatz (Konferenz)
Englisch
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