直流电沉积法制备纳米晶体镍镀层及其热稳定性的研究

Synthesis and Thermal Stability of Nanocrystalline Nickel Coatings by Direct Current Electrodeposition

摘要:

利用直流电沉积技术，系统分析电流密度和镀液糖精浓度对纳米晶体镍性能的影响。电流密度在0.5-1.5 A/dm2 范围内时，可调节糖精浓度制备出415-603Hv的显微硬度宽分布的纳米晶镀层。小电流密度0.5 A/dm2 时，随糖精浓度增大，镀层(200) 面衍射强度增强，结构由(111), (200)双织构向(200)面转变，且镀层内应力值降低，增大到1.2g/L时，内应力降为0MPa。镀层晶粒尺寸为28~98nm时，直到600℃晶粒才开始长大，结构稳定性较好；晶粒尺寸为10nm时，晶粒在317℃异常长大，其结构稳定性显著下降。

Abstract:

The influence of current density and saccharin concentration on nanocrystalline nickel coatings synthesized by direct current electrodeposition was systematically analyzed. For current densities ranging from 0.5 A/dm2 to 1.5 A/dm2, nanocrystalline nickel with broad microhardness distribution ranging from 415 Hv to 603 Hv could be synthesized by adjusting saccharin concentration. The preferred orientation in the deposits existed at 0.5 A/dm2 and changed progressively from a (111), (200) double orientation texture to a (200) orientation texture as saccharin concentration increased. The internal stresses of the samples at 0.5 A/dm2 decreased to nearly 0 MPa as saccharin concentration increased to 1.2 g/L. The results of DSC curves show that the samples grew until 600 癈 and were stable near to bulk nickel when grain size ranged from 28 nm to 98 nm. However, when grain size was 10 nm, the samples initially grew abnormally at 317 癈. Moreover, thermal stability decreased sharply.