超临界技术在石墨烯量子点脉冲复合镀镍中的应用研究

Application of Supercritical Technology in Pulse Composite Nickel Plating of Graphene Quantum Dots

为了适应目前航空航天、汽车以及高端设备制造业迅速发展的环境,以具有独特性能的石墨烯量子点(GQDs)作为第二相添加物,采用超临界脉冲电沉积技术制备Ni基纳米复合镀层,探究了超临界条件下脉冲频率对复合镀层的微观结构和耐腐蚀性、显微硬度、耐磨性等性能的影响。结果表明:在超临界条件下脉冲频率为2000 Hz时,所制备镀层的微观结构呈致密化和均匀化,并且呈现出更好的球状度。XRD检测显示,超临界条件可以改变结晶的择优取向,合适的脉冲频率可以细化镀层晶粒,减小晶粒尺寸。当在超临界条件下脉冲频率为2 000 Hz时,所制备镀层各项性能更为优异。电化学试验研究表明,其容抗弧半径最大、自腐蚀电位最高、腐蚀电流密度最低以及容抗模量最大,耐腐蚀性最为优异。2000 Hz脉冲频率所制备镀层其显微硬度最高,达到835.4 HV2 N,且具有最优的耐磨性,磨痕截面积为1 582μm^(2),显微硬度和磨痕截面积分别为脉冲频率为100,1 000,3 000 Hz和常温常压所制备镀层的126%、107%、121%和134%以及47.6%、57.1%、71.5%和44.3%。在超临界条件下,2 000 Hz脉冲频率所制备的石墨烯量子点复合镀层具有较为优异的耐腐蚀性和耐磨性。

In order to adapt to the current rapid development of aerospace,automotive,and high⁃end equipment manufacturing industries,using graphene quantum dots(GQDs)with unique properties as the second phase additive,Ni⁃based nanocomposite coatings were prepared by supercritical pulse electrodeposition technology.The effect of pulse frequency on the microstructure,corrosion resistance,microhardness,wear resistance and other properties of composite coatings under supercritical conditions was investigated.Results showed that when the pulse frequency was 2000 Hz under supercritical conditions,the microstructure of the prepared coating was densified and uniform,with better sphericity.XRD results showed that supercritical conditions could change the preferred orientation of crystallization and the appropriate pulse frequency could refine the coating grains and reduce the grain size.At a pulse frequency of 2000 Hz under supercritical conditions,the proper⁃ties of the prepared coating were more excellent.Electrochemical experiments showed that it had the largest capacitive arc radius,the highest self⁃corrosion potential,the lowest corrosion current density,and the largest capacitive modulus,so the coating had the most excellent corro⁃sion resistance.The coating prepared at 2000 Hz pulse frequency had the highest microhardness,reaching 835.4 HV_(2N),and had the best wear resistance with a wear scar cross⁃sectional area of the coating of 1582μm^( 2).The microhardness and wear scar cross⁃sectional area were 126%,107%,121%and 134%,and 47.6%,57.1%,71.5%and 44.3%of the coatings prepared with pulse frequencies of 100,1000,3000 Hz and under room temperature and pressure,respectively.Under supercritical conditions,the graphene quantum dot composite coating prepared at a pulse frequency of 2000 Hz had excellent corrosion resistance and wear resistance.