论文部分内容阅读
本文用ＳＥＭ、ＥＤＡＸ、ＸＲＤ和显微硬度计分析了４５钢表面激光熔覆Ｎｉ基ＺｒＯ_２（４Ｙ）陶瓷层的组织结构与性能。结果表明：激光熔覆的Ｎｉ基ＺｒＯ_２（４Ｙ）陶瓷层出现分层现象，表层为致密的ＺｒＯ_２陶瓷层，与钢基体结合的中间层为Ｎｉ基合金；陶瓷层主要由ｔ－ＺｒＯ_２相与少量Ｎｉ基γ固溶体组成，激光的快速熔凝过程抑制了ＺｒＯ_２的ｔ→ｍ相转变；在最优激光参数条件下，可获得与钢基结合良好的致密ＺｒＯ_２陶瓷熔覆层，其硬度值达到ＨＶ_（０．２）１７２０；激光参数偏离最优值时，熔覆的陶瓷层出现微孔、裂纹，且硬度大幅度下降。
In this paper, the microstructure and properties of Ni-based ZrO_2 (4Y) ceramic coatings on 45 steel were analyzed by SEM, EDAX, XRD and microhardness tester. The results show that the laser cladding ZrO_2 (4Y) ceramic layer appears delamination, the surface is dense ZrO_2 ceramic layer, the intermediate layer combined with the steel substrate is Ni-based alloy; the ceramic layer is mainly composed of t-ZrO_2 phase and a small amount Ni-based γ solid solution. The laser rapid solidification process retards the t → m transformation of ZrO_2. Under the optimal laser parameters, a dense ZrO_2 ceramic cladding layer with good bonding with the steel matrix can be obtained. The hardness reaches HV_ (0.2) 1720. When the laser parameters deviate from the optimal value, the micro-cracks and cracks appear on the cladded ceramic layer, and the hardness decreases greatly.