Papers by Author: Hong Yuan Xu

Abstract: Slurry pumps are used to transport the liquid fluids with solid particles in the industries. The materials of flow passage in a slurry pump are subjected to severe damage due to abrasive erosion. This paper compares the abrasive erosion for an engineering ceramics i.e. hot pressed Si3N4 ceramics and a high chrome cast iron i.e. Cr26 by laboratory test and industrial operation. The results indicate that the erosion rate of Cr26 is much larger than that of hot pressed Si3N4 ceramics under the same test conditions. That indicates that the engineering ceramics is a promising alternation of the expensive material such as Cr26 in the application of slurry pumps. It is noted that the erosion pattern such as scale ripple has the similar features for both materials, even the hardness of hot pressed Si3N4 ceramics is much higher than Cr26. Further, the scale ripple is suspected to be originated from the relatively weak grain boundary and enhanced by cavitation.

Abstract: A slurry pot tester was used to evaluate the erosion behavior of alumina (Al2O3), zirconia toughened alumina (ZTA), and silicon nitride ceramics. The eroded surface of sample was studied by scanning electronic microscope and the primary erosion wear mechanisms for ceramic materials were analyzed. On the same experimental condition, erosion wear resistance of materials follows this rule: Si3N4>ZTA>Al2O3. The key factor affecting erosive wear performance of ceramics is their microstructure. The primary erosive wear mechanisms for Al2O3, ZTA and Si3N4 ceramics are lateral crack propagation, whole grains pulled out and plastic deformation. The erosive wear performance of Si3N4 ceramic is the best in this experiment, due to their microstructure morphology with elongated grains.

Abstract: Engineering ceramics have a high application potential for wear-protection of different equipment used for electric power generating, mining and mineral industries. The ZTA (zirconia toughened alumina) and alumina (92%, 95%) have been prepared. Effects of varying the impact velocity and volume content of erodent particle and erosive time are investigated. Scanning electron microscopic examination of the eroded ceramic surfaces provides insights into the erosive wear mechanisms. The material removal processes include chipping out of lateral cracks caused by impact of the erodent particles, grain boundary cracking and grain pull out, as well as plastic deformation caused by the repeated sliding and impact of the particles.