The use of metals is of great importance for social progress. However, native oxide layers on metal surfaces, typically formed in the ambient atmosphere, often have a negative influence on the properties and performance of materials in metal joining operations. Thus, the reduction of oxide layers, referred to as surface deoxidation, is an important part of current research efforts, and its successful implementation could offer a range of benefits to the metalworking industry. Conventional methods of deoxidation, such as chemical treatment or grinding, while partially effective, pose challenges due to potential alteration of surface properties. In contrast, the use of non-thermal plasmas in hydrogen-containing atmospheres represents a promising alternative. In particular, dielectric barrier discharge (DBD) appears to be one of the most advantageous candidates, as it is effective at atmospheric pressure and has a relatively simple design that can be scaled up to industrial applications. Nevertheless, despite the high potential of the method, the deoxidation effect and mechanisms of the process on various metal surfaces have not been properly investigated. The work reveals the efficiency and possible mechanisms of deoxidation of copper and iron oxidized surfaces in a non-thermal DBD plasma. The effect of a DBD plasma was examined at 1000 hPa in different atmospheres such as industry-relevant Ar and Ar/H2 as well as promising oxygen-free Ar/SiH4. By varying the operating parameters of the process, such as treatment time and surface temperature, the optimal conditions for the complete reduction of copper and iron surface oxides were identified. As a result, a possible model for surface oxide reduction under DBD plasma in hydrogen-containing gases was proposed.weiterlesen