Experimental investigation of cavitation erosion-induced surface damage and particle shedding from PTFE

• PTFE particles exhibit two distinct micro-morphologies of brittle and ductile, corresponding to cavitation sites. • Cavitation particles are negative replicas of cavitated surfaces, which is clarified from a more microscopic perspective. • Crystallinity of PTFE is reduced after cavitation erosion, accompanied by oxidation reactions. Under ultra-clean operating conditions, cavitation, combined with shear forces and fluctuating pressures, can cause surface damage and generate wear particles. Polytetrafluoroethylene (PTFE), widely used in ultra-clean flow control due to its excellent corrosion resistance, is also susceptible to erosion under cavitation. This study investigates cavitation-induced erosion of PTFE using an ultrasonic cavitation test bench. A comprehensive characterization and analysis of the eroded surfaces and released particles were performed. Results revealed that PTFE particles exhibit two distinct morphologies—brittle and ductile—on the micrometer scale, corresponding to cavitation sites. Moreover, cavitation was found to decrease PTFE crystallinity, with evidence suggesting that particle release may be accompanied by chemical reactions. These findings provide valuable insights into PTFE behavior under cavitation conditions.