Destruction mechanisms of epoxybased composite filled with metal powder under cavitation attack

Abstract

The samples of epoxy compound with a powder filler and without it are tested on cavitation wear. The powder of aluminum bronze BrAZhNMts9–4–4–1 is used as a filler. The powder is obtained by filing the rod of the bronze. The composition of the epoxy compound is 100 parts of the resin K‑153 plus 12 parts of the hardener (polyethylene epolyamine). The distribution of the bronze particles in the epoxy compound follows the law close to the exponential one, the average particle size is equal to approximately 27 μm, and the volume fraction of the bronze powder in the compound is about 9,5 percent. The tests are conducted using the ultrasonic magnetostrictve vibrator UZDN‑2T in fresh water of room temperature, the frequency and amplitude of the vibrator horn end equal to 22 kHz and 28 µm respectively. The distance between the horn end and the sample surface is 0,5 mm. During the experiments the wear of the samples is evaluated by their weighting on analytical scales with step-type indication of 0,1 mg, measuring the surface roughness and the microhardness of the bronze particles in the composite is carried out as well. It has been shown that the addition of the bronze particles into the epoxy compound not only changes the kinetics of cavitation wear of the polymer but also decreases its cavitation resistance. The decrease in cavitation resistance caused by bronze particles addition is attributed to the fact, that the boundary between a metal particle and epoxy matrix is a «weak» spot, and the destruction of polymer begins from this boundary area under cavitation attack.