Electrocrystallization Mechanism、 Structure and Microhardness of Ni-W-P Alloy Eletrodeposits

Abstract

应用循环伏安、恒电位阶跃和 X射线衍射( XRD)等方法研究了 Ni-W-P合金电沉积特点和镀层结构与显微硬度 .结果表明,在以柠檬酸铵为配体的溶液中, Ni-W-P合金沉积层较 Ni-W合金有较低的电化学活性 .根据电位阶跃的 i~ t曲线分析表明,在玻碳电极上 Ni-W-P合金电结晶过程遵从扩散控制瞬时成核三维成长模式进行,随着过电位的增加,电极表面上晶核数增多 . XRD试验结果表明, Ni-W-P合金镀层呈现明显的非晶态特征 .所获得的 Ni-W-P合金电沉积层的显微硬度在 450 kg· mm- 2左右 .The electrodeposition characteristics,structure and microhardness of Ni-W-P alloy have been studied by the methods of cyclic voltammetry, potentiostatic step and X-ray diffraction(XRD). The results showed that Ni-W-P alloy electrodeposit obtained from the solution containing ammonium citrate as complexing agent presented lower electrochemical activity compared with Ni-W alloy electrodeposit. Based upon the i~ t curves of potentiostatic step, it was revealed that electrocrystallization of Ni-W-P alloy on glassy carbon electrode followed the mechanism of instantaneous nucleation and three dimensional growth with diffusion controll.The crystal nucleus number on the surface of electrode was raised by the increase of overpotential.XRD experimental results showed that the Ni-W-P alloy electrodeposits obtained were obviously of the amorphous structure, and the microhardness of the alloy was about 450 kg/mm2 at the stated plating solution and conditions.国家自然科学基金!(29773039

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