电火花沉积Ni/Ti(C,N)金属陶瓷复合涂层的组织及性能研究

目的提高H13模具钢的表面耐磨性,探索金属陶瓷涂层的应用。方法分别用Ti(C,N)基金属陶瓷棒和纯镍棒作为电极,氩气为保护气体,在H13钢表面电火花沉积制备Ni/Ti(C,N)金属陶瓷复合涂层。使用X射线衍射仪对涂层的相组成进行了分析,并用扫描电子显微镜及能谱仪观察涂层的微观结构和元素分布情况,采用显微硬度计和CSM球盘式摩擦计对涂层的显微硬度和不同载荷下的耐磨性进行测试。结果涂层表面为单脉冲沉积斑点堆积而成的溅射状形貌,Fe和Ti元素整体上呈现出分区富集的特征,强化层主要物相包括TiC(0.7)N(0.3)、Ni(17)W3、Ni-Cr-Co-Mo和Fe3Ni2。涂层截面组织均匀,缺陷较少,厚度约为31μm,Fe、Ti和Ni元素均在界面处发生扩散,形成了良好的冶金结合,过渡层与基体相互混合,呈现出机械式的咬合结构。涂层的显微硬度实测最高值达1420HV,约为基体的5.4倍。涂层具有比基体更低的摩擦系数,且30 min内的磨损质量损失仅为基体的1/2,涂层磨损机理主要为粘着磨损和轻微的磨粒磨损。结论在H13钢表面电火花沉积制备的Ni/Ti(C,N)金属陶瓷复合涂层可提高其表面的硬度、耐磨性,且具有一定减摩性,可以起到延长模具寿命的作用。

Microstructures and Properties of Ni/Ti(C,N) Composite Cermet Coating Prepared by Electrospark Deposition

The work aims to improve the surface wear resistance of H13 die steel and explore the application of cermet composite coating.The Ni/Ti(C,N)composite cermet coating was prepared on the surface of H13 steel by electrospark deposition with Ti(C,N)-based cermet rods and pure nickel rods as electrode materials and argon gas as shielding gas.The phase composition of the coating was analyzed by X-ray diffraction(XRD).Scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)were used to study the surface and cross-section morphologies and elements distribution of the coating.The microhardness and wear resistance of the coating under different loads were measured with a microhardness tester and a CSM ball-on-disk tribometer.The surface of the coating was sputtered by single-pulse deposition spots.Fe and Ti elements exhibited the characteristics of partition enrichment.The main phases of the strengthening layer included TiC0.7N0.3,Ni17W3,Ni-Cr-Co-Mo and Fe3Ni2.The coating had a uniform cross-section structure with few defects and a thickness of about 31μm.Fe,Ti and Ni elements were all diffused at the interface to form a good metallurgical bond.The transition layer and the substrate were mixed with each other to present a mechanical occlusion structure.The measured microhardness of the coating was up to 1420 HV,which was about 5.4 times as much as that of the steel.The average friction coefficient of the coating was lower than that of the H13 steel substrate,and the wear weight loss within 30 min was only 1/2 of that of the substrate.The main wear mechanism of the coating was slight abrasive wear and adhesive wear.The Ni/Ti(C,N)composite cermet coating deposited on the surface of H13 steel can improve the hardness and wear resistance and has certain antifriction,which can play a role in prolonging the service life of the die.