Cavitation demage morphology of glass-ceramics based on basalt

Abstract

Cavitation is a kind of wear and represents formation, growth and collaps of steam or vapor gas bubbles in a flowing fluid. Collaps of the bubble creates shock waves and micro–jet that are damaging materials in contact with the fluid that flows. It has been shown that the impact formed by collapsing cavitation bubbles cause damage and mass loss of the material, i.e., cavitation erosion. Basalt–based glass ceramics obtained by processes of melting, casting and thermal treatment of the basalt aggregate proved to be suitable for use in conditions of high cavitation loads. The experiment was conducted using an ultrasonic vibration method with stationary sample (ASTM G32 standard). A change in the sample mass in function of the cavitation time was monitored for the evaluation of cavitation resistance. The level of degradation of the sample surface was quantified using the image analysis. The change in the morphology of the sample surface with the test time was followed by scanning electron microscopy. Analyzing the progression of erosion samples of glass-ceramics, it can be concluded that the mass loss is small, for 120 min exposure is 3.53 mg, with a cavitation rate of 0.03 mg/min and total surface damage of the sample of 12%. This technical ceramics shows high resistance to the effect of the cavitation.