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在2024铝合金上采用了二次浸锌的预处理方法,以化学镀镍,电镀铜作为过渡层的特殊工艺,再利用磁过滤脉冲偏压电弧离子镀技术制备了Zn/Ni/Cu/Cr/CrN多层梯度膜。利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、显微硬度仪和腐蚀测量仪等测试手段分析薄膜的成分、结构、表面形貌、显微硬度、耐腐蚀性等特性。结果表明:多层膜性能梯度分布,结构交替变化,从而减少膜基的内应力,提高了铝合金上CrNx涂层的结合力,能够有效的解决铝合金上镀硬质陶瓷膜的热适配和晶格错配度大的难题。表面氮化物多层膜均匀致密,未出现龟裂,颗粒的数量和尺寸大大减少。氮化物以CrN(220)为主要相,氮化物膜层的显微硬度达到2600 HV,是镍磷层的3倍,与铝基体相比,其表面显微硬度提高了22倍多,耐腐蚀性提高了400 mV。这样的CrNx薄膜能使铝合金表面具有高硬度和良好的耐腐蚀性,对轻合金表面涂覆超厚硬质膜具有一定的研究意义。
In the 2024 aluminum alloy, the pretreatment method of secondary zinc immersion was adopted. The special process of electroless nickel plating and copper electroplating was used as the transition layer, and then Zn / Ni / Cu / Cr / CrN multilayer gradient film. The composition, structure, surface morphology, microhardness and corrosion resistance of the films were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness tester and corrosion tester. The results show that the gradient distribution and the structure of multi-layer films change alternately, so as to reduce the internal stress of the film base and improve the bonding strength of the CrNx coating on the aluminum alloy, which can effectively solve the thermal fit of the hard alloy film on the aluminum alloy And the degree of lattice mismatch problems. The surface nitride multilayer film is uniform and compact, no cracks appear, and the number and size of particles are greatly reduced. Nitride to CrN (220) as the main phase, the nitride layer hardness of 2600 HV, nickel-phosphorus layer is 3 times, compared with the aluminum matrix, the surface micro-hardness increased by 22 times, corrosion resistance Sex increased by 400 mV. Such CrNx film can make the aluminum alloy surface with high hardness and good corrosion resistance, light alloy surface coated with a thick hard film has some significance.