Emissions in Thermal Spraying - Development of aSuitable Test Method and Evaluation of Measurementsin Laboratory as well as in Industrial Scale

In comparison to associated technologies e.g. welding, only limited knowledge exists concerning health related aspects of thermal spray emissions. Furthermore thermal spraying is known as a versatile technique which is employed in multiple applications and industries utilizing various feedstock materials as well as technologies. This vast diversity results in a complex situation in order to assess possible health hazards as well as to comply with future legal regulations. Within this work the development of a universal test method, adapted to the requirements of thermal spraying, as well as measurements of thermal spray emissions in laboratory and industrial scale are presented. Requirements for a test method are the ability to characterize the particulate load as well as the chemical composition of the particulate matter. Analysis of the chemical composition includes the differentiation of the oxidation state for Chromium, which is motivated by significant differences in toxicity between Cr(III) as well as the carcinogenic Cr(VI). The developed method based on HPLC/ICP-MS as well as laser photometry was used to perform emission measurements. Within these tests different processes (HVOF, APS, EAW) as well as feedstock materials containing Cr, Ni, WC and/or Co were examined in different situations as well as measurement positions, in order to assess possible treats.