Sand erosion performance of B4C based ceramic nozzles

Abstract

B4C/Al2O3/TiC ceramic composites with different content of TiC were produced by hot pressing. The effect of TiC content on the microstructure and mechanical properties of this composite has been studied. The sand erosion performance of the nozzles made from this composite was examined with an abrasive air-jet. Results showed that chemical reaction took place for the system during hot pressing, and resulted in a B4C/Al2O3/TiB2 composite with high density and improved mechanical properties compared to B4C/Al2O3 composite. The sintering temperature was lowered from 2150 °C for B4C/Al2O3 to 1950 °C for B4C/Al2O3/TiC composite. The hardness of B4C/Al2O3/TiC ceramic nozzles had an important influence on the erosion rate in abrasive air-jet machining. The nozzle materials with high hardness showed lower erosion rate. Analysis of the B4C/Al2O3/TiC nozzle eroded bore surfaces showed that the entry bore surface exhibited a brittle fracture induced removal process, while the center bore surface showed plowing and polishing type of material removal mode. Both types (fracture and plowing) of material removal model seem to be occurred at the exit bore surface.