【摘要】 利用粉末冶金法制备TiB2和TiC复合材料熔敷棒,并通过电火花沉积在点焊镀锌钢板用电极的表面制备TiB2和TiC复合涂层。利用SEM和XRD分析涂层的微观结构和物相,运用点焊实验测试涂层电极的使用寿命。结果表明:复合材料熔敷棒中TiB2和TiC颗粒细小均匀,电火花涂层致密无分层,涂层物相为Cu、TiB2和TiC;Cu从基体扩散到涂层表面,涂层表面Cu含量(原子分数)达到28%,过渡层出现Cu和Ti的梯度分布,涂层与基体间为牢固的冶金结合;复合涂层存在少量裂纹,其显微硬度达到850HV,高于TiB2涂层和TiC涂层硬度;点焊时电极头部的平均磨损率大大降低,电极的点焊寿命比无涂层电极提高4倍。更多还原

【Abstract】 TiB2 and TiC composite rod was prepared by compacting and sintering,and the TiB2/TiC coating was deposited by electrosparking onto the surface of cupper alloy electrode used for spot welding of zinc-coated steel plate. Then the coating structure and phase compositions were characterized by SEM and XRD,and lifespan was examined by spot-welding test. The results suggest the TiB2 and TiC particles are fine and dispersive distributed,the TiB2 and TiC composite coating is free from pore and delamilation and a few cracks are spotted. Major phases of the coating are Cu,TiC and TiB2 and Cu diffuses from the substrate into the top surface of the coating during electrosparking,reaching a concentration of 28% atomic fraction and forming an atomic bonding between the coatings and the substrate. The microhardness of TiB2 and TiC composite coating reaches 850HV,which is much larger than that of TiB2 coating and TiC coating. The electrode is hardened by TiB2 and TiC composite coatings so that the wear of the electrode during welding is reduced significantly. As a result,the spot-welding life of TiC and TiB2 coated electrode is prolonged by four times.更多还原