CeO_(2)添加量对激光熔覆TiB_(2)-TiC/Ni复合涂层组织和性能的影响

Effect of CeO_(2) Addition Amount on Microstructure and Properties of Laser Cladded TiB_2-TiC/Ni Composite Coating

利用激光熔覆技术在TC4钛合金表面制备了添加质量分数1.0%,1.5%,2.0%CeO_(2)的TiB_(2)-TiC/Ni复合涂层,研究了复合涂层的物相组成、显微组织和硬度,讨论了搭接率(30%,40%,50%)对最佳CeO_(2)含量条件下复合涂层试样摩擦磨损性能的影响。结果表明:复合涂层均由TiB_(2)、TiB、α-Ti、TiC、Ni_(3)Ti、Cr_(23)C_(6)、Ti_(2)Ni、Cr_(3)C_(2)、γ-Ni等相组成;添加质量分数1.5%CeO_(2)复合涂层的组织最为均匀致密,细化效果明显;随着CeO_(2)添加量的增加,复合涂层的硬度先增后降,添加质量分数1.5%CeO_(2)复合涂层的硬度最高,约为1 015 HV。CeO_(2)的最佳添加质量分数为1.5%,在此条件下随着搭接率的增加,试样的磨损质量损失先减小后增大,当搭接率为40%时,磨损质量损失最小,磨损机理为磨粒磨损。

The TiB_2-TiC/Ni composite coating added with 1wt%,1.5wt% and 2wt% CeO_(2) was prepared on the surface of TC4 titanium alloy by laser cladding technique.The phase composition,microstructure,and hardness of the composite coating were studied,and the effect of lapping rate(30%,40%,50%) on the friction and wear properties of the composite coating sample under the optimal CeO_(2) content condition was discussed.The results show that the composite coating consisted of TiB_2,TiB,α-Ti,TiC,Ni_3Ti,Cr_(23)C_6,Ti_2Ni,Cr_3C_(2) and γ-Ni phases.The microstructure of the composite coating added with 1.5wt% CeO_(2) was the most uniform and dense,and the refinement effect was obvious.With the increase of CeO_(2) addition amount,the hardness of the composite coating increased first and then decreased.The hardness of the composite coating added with 1.5wt% CeO_(2) was the highest of about 1 015 HV.The optimal mass fraction of CeO_(2) was 1.5%;under this condition,the wear mass loss of the sample decreased first and then increased with the increase of lapping rate.When the lapping rate was 40%,the wear mass loss was the smallest,and the wear mechanism was abrasive wear.