Construction Productivity Advancement Research (CPAR) Program: Cavitation- and Erosion-Resistant Thermal Spray Coatings
CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL
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This study demonstrated the effectiveness of thermal spray cavitation and erosion-resistant metal coatings for hydroelectric and utility plant turbines and pumps. Of 21 thermal spray coatings tested, Stellitetrade name 6 applied by the high-velocity oxyfuel HVOF process had the lowest cavitation rate 11.7 mgh. This was higher than the corresponding rate of 3.2 mgh for 308 stainless steel weld reference. In slurry erosion wear testing, the volume loss for HVOF-applied Stellitetrade name 6 was 5.33 mm3h, much lower than volume losses for 304 stainless steel and A572 carbon steel. The field applicability of Stellitetrade name 6 was successfully demonstrated on a hydroelectric pumpturbine. Stellitetrade name 6 deposited by the HVOF process should be considered for repair of damage resulting from erosion and subsequent cavitation caused by surface roughening. Stellitetrade name 6 coatings should also be considered for the mitigation of galvanic corrosion. Damage caused by direct cavitation should be repaired by welding. Advanced iron-based alloys such as NOREMtrade name, D-CAVtrade name, CaviTectrade name, and Hydroloytrade name should be considered for use due to their superior cavitation resistance. The use of thermal spray coatings such as HVOF-applied Stellitetrade name 6 should also be considered for repair of pumps subjected to erosion and subsequent cavitation caused by surface roughening.
- Coatings, Colorants and Finishes