Q235钢表面电火花沉积铁基非晶改性层及其性能

Electrospark deposition of amorphous Fe-based modified layer on surface of Q235 steel and its properties

采用电火花沉积技术在Q235钢表面制备了Fe基改性层,以提高Q235钢的硬度、耐磨性和抗高温氧化性。通过X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)和高温循环氧化试验对比了基体和改性层的微观结构及抗高温氧化性能。结果表明,所得改性层为非晶态结构,在700℃退火6 h能实现晶化转变;改性层厚度约为12.5μm,表面呈现丘陵状形貌,与基体之间存在很好的冶金结合;电极成分中的Al、Cu和Sn分布于改性层整个表面,并且在凸起和凹陷处的含量更高;相对于基体,改性层具有更好的抗高温氧化性能。改性层的显微硬度为265.90 HV,高于基体和晶化转变改性层,耐磨性也更优。

A Fe-based modified layer was formed on the surface of Q235 steel by electrospark deposition to improve its hardness, wear resistance, and high-temperature oxidation resistance. The microstructure and high-temperature oxidation resistance of the substrate and the modified layer were compared by X-ray diffraction(XRD), scanning electron spectroscopy(SEM), energy-dispersive spectroscopy(EDS), and high-temperature cyclic oxidation testing. The results showed that the Fe-based modified layer is amorphous and transfers to be crystalline after being annealed at 700 ℃ for 6 hours. The modified layer was 12.5 μm thick with a hilly surface morphology and a good metallurgical bonding to the substrate. The elements i.e.Al, Cu, and Sn from the electrodes were distributed over the surface of modified layer, and their contents at the convex and concave positions were higher than elsewhere. The high-temperature oxidation resistance of the modified layer was better than that of Q235 steel substrate. The modified layer had a higher microhardness(265.90 HV) than the substrate and the crystallized one(that is the modified layer after being annealed at 700 ℃ for 6 hours), and better wear resistance than the other two.