标题：Layered structures in ceramic nozzles for improved erosion wear resistance in industrial coal-water-slurry boilers
作者：Deng Jianxin;Yun Dongling;Zhou Houmin
作者机构：[Deng, J] School of Mechanical Engineering, Shandong University, Jinan, 250061 Shandong Province, China;[ Yun, D] School of Mechanical Engineering, Sh 更多
通讯作者地址：[Deng, JX]Shandong Univ, Sch Mech Engn, Jinan 250061, Shandong, Peoples R China.
关键词：Nozzles;Ceramic materials;Residual stress;Layered materials;Slurry erosion
摘要：The nozzle is the most critical part in the coal-water-slurry (CWS) boilers. Ceramics being highly wear resistant have great potential as CWS nozzle materials. In this paper, Al_2O_3/(W,Ti)C + Al_2O_3/TiC layered ceramics (LN1, LN2, and LN3) with different thickness ratios among constituent layers were developed to be used as nozzles in CWS boilers. CWS burning tests in a boiler with these nozzles were carried out. The erosion wear behavior of the layered nozzles was investigated and compared with an unstressed reference nozzle (N5). Results showed that the layered ceramic nozzles exhibited an apparent increase in erosion wear resistance over the unstressed reference one. The mechanisms responsible were found to be that layered structure in the CWS nozzles can improve the hardness and fracture toughness of the external layer, and reduce the temperature gradients and the thermal stresses at the exit of the nozzle during CWS burning processes. It is suggested that layered structures in ceramic nozzles is an effective way to improve the erosion wear resistance over the stress-free ceramic nozzles in industrial CWS boilers.