材料期刊网

目的 进一步提高以45#钢为基体的等离子喷涂Ni基WC金属陶瓷涂层综合性能.方法 采用不同激光重熔工艺参数对涂层进行处理,通过划痕实验测定涂层的内聚强度和与基体的结合强度,前者由划痕实验中的锥形投影面积确定,内聚强度与锥形投影面积成反比,后者根据划痕仪反馈数据临界载荷Lc确定.结果300 W激光重熔后,涂层锥形投影面积A为101,小于重熔前的276,即涂层内聚强度提高.激光重熔后的临界载荷Lc为68 N,大于重熔前的45 N,涂层与基体的结合强度增大.300、800、1200 W激光功率下,涂层锥形投影面积分别为101.6、56.7、198.0,临界强度分别为68、77、41 N.激光功率达到1500 W时,涂层脱落.即本试验数据中,激光功率为800 W时,涂层的内聚强度和结合强度最佳.结论激光重熔等离子喷涂Ni-WC金属陶瓷涂层后,涂层内聚强度和结合强度都有显著提高.不同的激光参数对涂层的性能有很大差别,适当的参数范围可达到理想效果,若激光功率参数取值过大,涂层产生的残余应力大于内聚力时会导致涂层脱落,反而降低涂层性能.

The work aims to further improve overall performance of plasma spraying Ni-based WC cermet coating on 45# steel substrate by treating the coating with different laser remelting process parameters. Cohesive strength of the coating and bonding strength with substrate were measured by conducting strength scratch test, the former was determined by cone projected area in the scratch test, the cohesive strength was inversely proportional to the cone projected area. The latter was determined based on critical loadLc in feedback data of scratch tester. After 300 W laser remelting, coating cone projected area A was 101 (less than 276 before remelting), cohesive strength of the coating has improved. After laser remelting, critical loadLc was 68 N, greater than 45 N before the remelting, bonding strength of the coating to substrate increased. The cone projected area was 101.6, 56.7 and 198.0 while critical strength was 68 N, 77 N and 41 N, respectively, at the laser power of 300 W, 800 W and 1200 W. The coating fell off at the laser power of 1500 W. Both cohesive strength and bonding strength of the coating improve significantly after laser remelting plasma sprayed Ni-WC cermet coating. In the test data, cohesive strength and bonding strength are the best at the laser power of 800 W. Performance of the coating varies greatly from different laser parameters, appropriate range of parameters can contribute to desired effect. Provided that the laser power parameter is too high, the coating falls off and coating performance decreases when residual stress produced by the coating is greater than cohesive force.