脉冲电沉积Ni-W基复合镀层的制备及其性能研究

发布时间：2018-03-14 06:37

  本文选题：复合镀层　切入点：纳米颗粒　出处：《中国石油大学(华东)》2015年硕士论文　论文类型：学位论文

【摘要】：电沉积技术经过几十年的发展,即满足了装饰上的需要,也对材料表面进行保护作用,成为工业上不可缺少的技术手段。近年来,由于复合电沉积技术制备的镀层具有优异的力学、热学、光学及电磁学性能,以及耐腐蚀、硬度高、抗高温氧化和耐磨等性能,所以,复合镀层成为研究的热点,引起了人们的普遍关注。本论文结合相关的研究,以Ni-W为基体金属制备含有LaCl_3、Al_2O_3的复合镀层,采用SEM、XRD等分析手段,确定复合镀层的最佳工艺条件,考察了工艺参数对复合镀层的影响;制备Ni-W/LaCl_3复合镀层,研究复合镀层的结构和耐腐蚀性能;制备Ni-W/LaCl_3-Al_2O_3复合镀层,并研究其高温氧化性能;分析了Ni-W、Ni-W/LaCl_3、Ni-W/Al_2O_3、Ni-W/LaCl_3-Al_2O_3不同镀层的耐腐蚀性能。具体的研究内容如下:通过设计正交实验确定Ni-W电沉积的优化参数,在此基础上,研究了单个的工艺参数对复合镀层性能的影响。结果表明,优化工艺为:硫酸镍50g/L,钨酸钠60g/L,柠檬酸钠100g/L,次亚磷酸钠40g/L,pH值为9,电流密度为40mA/cm2,温度为60℃。最佳工艺条件下,复合镀层更均匀平整,具有良好的硬度,耐高温、耐腐蚀性能;随着电流密度和电镀时间的增加,Ni-W镀层的硬度呈现先增大,后减小的变化规律。在优化的工艺条件下,研究添加稀土化合物LaCl_3制备Ni-W/LaCl_3复合镀层,结果发现:稀土化合物LaCl_3的最佳浓度为1g/L,此浓度下的Ni-W/LaCl_3复合镀层具有最大的厚度;比Ni-W镀层的表面致密,耐腐蚀性好。在Ni-W/LaCl_3复合镀层的基础上,制备和研究Ni-W/Al_2O_3-LaCl_3复合镀层,确定了Al_2O_3纳米粒子的最佳含量为20g/L;通过热处理的手段,进行高温氧化实验,采用XRD和SEM分析纳米粒子含量、氧化温度对氧化前后的复合镀层组的组织结构和表面形貌的影响。纳米粒子的加入提高了镀层硬度,细化晶粒;经过800℃,120min热处理之后,Ni-W/Al_2O_3-LaCl_3复合镀层比Ni-W/La Cl_3复合镀层氧化增重低42%,Al_2O_3纳米粒子可以提高镀层的抗高温氧化性能,但没有改变镀层的氧化机制。镀层600℃以前仍具有较好的性能,高温氧化以后,镀层由非晶态转变为晶态。最后采用电化学工作站测定了Ni-W、Ni-W/LaCl_3、Ni-W/Al_2O_3、Ni-W/LaCl_3-Al_2O_3镀层在3.5%NaCl溶液中的极化曲线和交流阻抗谱。结果表明:Al_2O_3纳米颗粒和稀土化合物LaCl_3的加入优化了镀层的表面形态,提高了镀层的致密性,提高了复合镀层的耐腐蚀性能;比较Ni-W、Ni-W/LaCl_3复合镀层、Ni-W/Al_2O_3复合镀层,Ni-W/LaCl_3-Al_2O_3复合镀层的耐蚀性,结果发现Ni-W/LaCl_3-Al_2O_3复合镀层具有最好的耐腐蚀性能。
[Abstract]:After decades of development, electrodeposition technology has met the need of decoration and protected the surface of materials. It has become an indispensable technical means in industry in recent years. Because of the excellent mechanical, thermal, optical and electromagnetic properties, corrosion resistance, high hardness, high temperature oxidation resistance and wear resistance, the composite coating has become a hot research topic, because of its excellent mechanical, thermal, optical and electromagnetic properties, such as high temperature oxidation resistance, high hardness, high temperature oxidation resistance and wear resistance. In this paper, the composite coating containing LaClS3Al2O3 was prepared with Ni-W as the base metal, and the optimum technological conditions of the composite coating were determined by means of SEM, XRD and other analytical methods. The influence of process parameters on the composite coating was investigated, the structure and corrosion resistance of the composite coating were studied by preparing Ni-W/LaCl_3 composite coating, and the oxidation performance of Ni-W/LaCl_3-Al_2O_3 composite coating at high temperature was studied. The corrosion resistance of Ni-WN / LaCl3-Al2O3 coating is analyzed. The specific contents are as follows: the optimum parameters of Ni-W electrodeposition are determined by orthogonal design. On this basis, the effects of single process parameters on the properties of composite coatings are studied. The optimized process is: nickel sulfate 50 g / L, sodium tungstate 60 g / L, sodium citrate 100 g / L, sodium hypophosphite 40 g / L, pH 9, current density 40 Ma / cm 2, temperature 60 鈩，

本文编号：1610083