Structural Design of Symmetric Laminated Ceramic Nozzle and Study on it ˉs Erosion Behavior

Al2O3+(W,Ti)C/Al2O3+TiC symmetric laminated ceramic materials and nozzles were produced by hot pressing in order to reduce the tensile stress at the entry and the exit region of nozzles and improve their erosion wear resistance. The test results show that both hardness and toughness of laminated ceramic materials are improved than the simple materials. Under same erosion conditions, the laminated ceramic nozzles have superior erosion wear resistance to that of the common ceramic nozzle; the experimental value of optimal layer thickness ratio is 2. In addition, the residual thermal stress generated in the preparation of laminated ceramic materials is analyzed by finite element method (FEM). Relationship between stress distribution and layer thickness ratio is obtained. It is suggested that the residual thermal stress lead to grain refining mechanical properties strengthening, and improve the erosion wear resistance of laminated ceramic nozzles improving. The theoretical value of optimal layer thickness ratio is 2, the experimental results are consistent with the theoretical prediction.