Radio-Frequency linear plasma process for heating of metallic surfaces

Innovative plasma processing provides localized heating of grounded metallic surfaces under low pressure. Here we exploit a specifically designed Cylindrical Capacitive Coupled Discharge (CCCD), Radio-Frequency (RF) powering the inner cylinder and keeping the outer one grounded. Both cylinders have a longitudinal slit. These slits are aligned to each other and faced to a grounded metallic plate (target) placed underneath. When RF power is applied, the plasma glows inside the inner tube cavity, but it leaks out through the slits and spreads onto the surface of the target as a linear slab of plasma. The parametric study of the process focuses on the nature of gas (Argon and Nitrogen), the pressure range (0.8-50 mbar), the RF power (100-1800 W), and the cylinders/plate gap distance (1 or 8 mm). The optimized operation of the plasma system provides the highest ion production in front of the plate. The fastest heating condition increases the target temperature to 614 degrees C within 1s exposure to plasma. Furthermore, simulations using the PlasimoTM software package gives several other essential parameters such as the ion flux and their energy carried to the plate. Experimental and numerical results are in good agreement. This device has demonstrated the proof-of-principle for plasma heating of metallic surfaces.