Systematic investigation of the temperature field in atmospheric plasma processing (APP)

The application of functional layers has increased constantly over the last decades [1]. Coating processes like plasma spraying allow efficient processing of metal or oxide particles, and have already found their application in various sectors of industries. Ultra fine cleaning, surface activation or surface modification with the plasma arc are currently also under investigation. In the scope of this work the influence of four different main parameters - current, working distance, feed speed and gas flow - on the arc temperature field was investigated. Due to the complex and different interactions of these parameters on the temperature field, the temperature distribution in steel and aluminium sheets was systematically examined. Furthermore, the relationship between the measured surface temperatures and the wettability of the substrates is being discussed. To generate the required data, two different experimental setups were used. First, the spatial heat distribution of the plasma arc was measured with a special arrangement of thermocouples. Second, the temperature fields during the plasma surface treatment of DC01 and Al 6082 substrates was measured. In addition to measurements with NiCr-Ni thermocouples an investigation with an IRCamera was performed. After the plasma surface treatment, the resulting wettability was determined by contact angle measurement. The obtained results and especially the measured temperature fields will be used in a next step to validate numerical simulations with SYSWELD and ANSYS CFX, which will be used for process optimization.