Sand erosion performance of B_4C/(W, Ti)c ceramic blasting nozzles

摘要

B_4C/(W, Ti)C ceramic composites with different contents of (W,Ti)C solid solution were produced by hot pressing for use in blasting nozzles. The effects of (W,Ti)C content on the microstructure and mechanical properties of this composite have been studied. The sand erosion performance of nozzles made from this material was examined with an abrasive air jet. Results show that fracture toughness, flexural strength and relative density continuously increase with increasing (W,Ti)C content up to 50 wt- percent for B_4C/(W,Ti)C composite, while hardness decreases with increasing (W,Ti)C content. The-sintering temperature was lowered from 2150 deg C for monolithic B_4C to 1850 deg C for B_4C/(W,Ti)C composite. The hardness of B_4C/(W,Ti)C ceramic nozzles had an important influence on erosion rate in sand blasting. Nozzle materials with high hardness showed a lower erosion rate. Analysis of eroded bore surfaces from B_4C/(W,Ti)C nozzles showed that the entry surface exhibited a brittle fracture induced removal process, while the centre bore surface showed a ploughing type material removal mode. Both material removal modes seem to occur at the exit bore surface.