Nonthermal Plasma Reduction of Nickel Oxide Layers by Atmospheric Pressure Dielectric Barrier Discharge in Argon/Hydrogen

In this work, the reduction kinetics of nickel oxide layers were investigated using dielectric barrier discharge plasma (DBD) in an argon–hydrogen atmosphere at 1000 mbar. The aim was to analyze the reduction behavior of thermally oxidized thick oxide layers as a function of treatment temperature and duration. To characterize the chemical composition and reduction progress, X‐ray photoelectron spectrocopy (XPS) measurements were performed at two analysis angles (80° and 30°). Additionally, morphological investigations using atomic force microscopy (AFM) and an analysis of the gaseous reaction products by mass spectrometry (MGA) were performed. The results show that the reduction of nickel oxide is highly dependent on the temperature. At room temperature, only partial reduction occurs near the surface, while at 100°C, significant but incomplete deoxidation is observed. Complete reduction of thick oxide layers is only achieved at 200°C within 90 s. Native oxide layers, on the other hand, can be completely reduced after just 10 s at 100°C. Mass spectrometry confirmed water, molecular oxygen, and carbon monoxide as the main reaction products. Overall, the results show that DBD plasma treatment is a fast, energy efficient, and surface‐preserving alternative to conventional thermal hydrogen reduction and enables complete reduction at significantly lower temperatures.