Ni-Co-Si_(3)N_(4)复合镀层表面激光加工微织构的形貌演化规律

Evolution Law of Laser-Textured Microstructure on Ni-Co-Si_(3)N_(4) Composite Coating Surface

为研究激光加工参数对镍基合金镀层表面微结构形貌的影响,采用电沉积法在45钢表面制备了Ni-Co-Si_(3)N_(4)复合镀层,使用波长为1070nm的光纤激光器对镀层表面进行加工。采用单因素法研究激光单脉冲能量密度、脉冲宽度和脉冲数量3个参数对微结构形貌的影响.得到微结构内径、外径、中心点高度、边缘高度和最低点高度等表征参数的演化规律。研究结果表明:激光与Ni-Co-Si_(3)N_(4)复合镀层相互作用.形成了球冠状凸包、W状凹坑、火山口凹坑、两个同轴火山口叠加状凹坑4种典型形貌;激光单脉冲能量密度增大,使得镀层表面微结构形貌由球冠状凸包向两个同轴火山口叠加状凹坑转变.脉冲宽度增加使得镀层表面微结构形貌由火山口凹坑向球冠状凸包转变,脉冲数量的增加可以增大火山口凹坑的深度与边缘凸起高度。

To study the effect of laser processing parameters on the surface texture morphology of Ni-Co-Si_(3)N_(4) composite coating,we used an electrodeposition technique to prepare the Ni-Co-Si_(3)N_(4) composite coating on the 45 steel surfaces and then processed the coating by optical fiber laser with 1070-nm wavelength.We studied the influence of pulse energy density,pulse width,and pulse number of laser on microstructure by single-factor method,obtaining the evolution law of characteristic parameters such as inside diameter,outside diameter,center point height,edge height,and nadir height of microstructure.The results showed that the laser interacts with the Ni-Co-Si_(3)N_(4) composite coating,forming four typical morphologies:spherical-cap-shaped bump,W-shaped pit,crater pit,and pit with double concentric holes.The surface microstructure changed from spherical-cap-shaped bump to pit with double concentric holes because of the increased pulse energy density and changed from crater pit to spherical-capshaped bump because of the increased pulse width.Besides,the depth and edge height of the surface microstructure increased because of the increased pulse number.