稀土掺杂的钛合金表面镍-氧化石墨烯镀层微观结构及摩擦行为研究

Study on microstructure and friction behavior of nickel-graphene oxide coating on rare earth doped titanium alloy surface

  • 摘要: 在瓦特镍型电镀液中掺入一定量稀土氧化铈(CeO2)和氧化石墨烯(GO),实现了TC4钛合金基体上Ni-GO-CeO2镀层制备,重点研究了稀土CeO2对复合镀层微观结构、晶粒尺寸、显微硬度和摩擦磨损性能的影响。结果表明,随CeO2掺入增加,镀层中孔洞和裂纹显著减少,且发现CeO2含量为3wt%时,镀层孔洞完全消失,但当CeO2含量超过3wt%时,镀层中CeO2将发生团聚,导致镀层再次出现孔洞和裂纹。XRD分析和显微硬度检测结果表明,CeO2含量为3wt%时,复合镀层Ni晶粒尺寸最小(42 nm),较未掺杂CeO2的镀层减小了28%,显微硬度最高(384.84 HV),较未掺杂CeO2的镀层提高了15.83%,但当CeO2含量超过3wt%时,镀层Ni晶粒尺寸增大,显微硬度下降。复合镀层摩擦特性研究表明,CeO2含量为3wt%时,镀层摩擦性能最优,摩擦系数最小(0.225),较未掺杂CeO2的镀层降低了24.24%,且磨损机制为轻微的磨粒磨损,但当CeO2含量超过3wt%,镀层摩擦性能降低,镀层表面磨粒磨损程度显著提高。

     

    Abstract: A specified amount of rare earth cerium oxide (CeO2) and graphene oxide (GO) was incorporated into the Watts nickel-type plating solution to facilitate the preparation of a Ni-GO-CeO2 plating on the TC4 titanium alloy substrate. The study focused on the influence of rare earth CeO2 on the microstructure, grain size, microhardness, and friction and wear properties of the composite plating layer. The findings indicate that as the concentration of CeO2 increases, the presence of holes and cracks in the plating layer significantly decreases. Notably, the imperfections in the plating layer were completely eliminated when the CeO2 content reached 3wt%. However, further increasing the CeO2 content beyond 3wt% leads to the agglomeration of CeO2 within the plating layer, which subsequently results in the reappearance of holes and cracks. XRD analysis and microhardness test results indicated that when the CeO2 content was 3wt%, the composite plating exhibited the smallest Ni grain size at 42 nm, which is 28% smaller than that of the undoped CeO2 layer. Correspondingly, the microhardness peaked at 384.84 HV, marking a 15.83% increase compared to the undoped CeO2 layer. However, with further CeO2 doping beyond 3wt%, there was an increase in Ni grain size and a decrease in microhardness. The friction characteristics of the composite plating revealed optimal performance when the CeO2 content was 3wt%. At this concentration, the friction coefficient reached its lowest value at 0.225, which is 24.24% lower than that of the undoped CeO2 plating, with only slight abrasive wear observed. However, increasing the CeO2 content beyond 3wt% led to a deterioration in the friction performance of the plating.

     

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