Effect of thermal cycling to the strength and fracture of SiC-based candle filters

In order to model the long-term durability and reliability of SiC-based, clay-bonded ceramic candle filters at complex service environments, it is first necessary to understand the mechanisms responsible for their failure in a manner that is scientifically and technologically tractable, i.e.- through experiments at the laboratory scale. In this work, the strength and fracture behavior of commercial SiC-based candle filter material were studied. The effect of thermal cycling between 150°C and 400°C on the strength and fracture toughness of the material was investigated. The behavior of as received material was used as reference for room temperature hoop and tensile strengths and for high temperature tensile stress-strain response. The microstructure and fracture surfaces of the test specimens were characterized using conventional techniques. It was found that thermal cycling increased both the tensile hoop and tensile axial strength of the material. It was also found that thermal cycling modified the path of crack propagation between the binder phase and the SiC-grains.