Erosion Wear Mechanisms of B4C/(W,Ti)C Ceramic Nozzles

B_4C/(W,Ti)C ceramic nozzle was prepared by hot pressing. The erosion behaviors of the resulting ceramic nozzle abraded by SiC, white emery, and umber emery abrasives were investigated on a GS-6 sand blast machine. The erosion-wear mechanisms of the ceramic nozzle were discussed based on stress analysis at various locations of the nozzle using finite element method and morphology observation of the entry and middle of the nozzle using scanning electron microscopy. It was found that the erosion-wear behavior of the ceramic nozzle was closely related with the types and grit sizes of the abrasive particulates. Namely, the harder SiC abrasive led to a more severe erosion-wear of the nozzle, while the softer umber emery abrasive led to a minimized erosion mass loss of the tested nozzle. Moreover, the erosion-wear mass loss of the ceramic nozzle increased with increasing grit size of the same abrasive, which corresponded to the different stress levels, the same as that for different abrasives types. At the same time, the erosion-wear mechanisms of the ceramic nozzles also varied with the variation of the abrasive types and the grit size, and with the locations along the lateral direction of the nozzle as well. Therefore, the nozzle was dominated by brittle fracture at the entrance and by stress fatigue in the middle as it was eroded by SiC and white emery abrasives, while it was characterized by stress fatigue in the presence of the umber emery abrasives.