In-Situ Monitoring of Gas Atmospheres During Debinding and Sin-tering of PM Steel Components

摘要

Processing of powder metallurgical components is related to high specific surfaces, in particular in the first stages of the process. Thus, high specific surfaces give rise to carbonization and oxidation during debinding and sintering due to reactions with degradation products of binders and additives. Since measurements in the furnace exhaust system may lead to ambiguous results, the objective of the present work is to observe reactions of PM components with the process atmosphere directly in the furnace. Therefore, in-situ FTIR gas phase measurements of the debinding and sintering of PM steel components were performed in reducing atmospheres. The results show the composition of the degradation products in the low temperature region <450 °C as well as carbothermic reactions and methane formation at temperatures >500 °C. With such informations, temperature and dwell time schedules may be optimized. As a conclusion, it is shown that in-situ monitoring of the gas phase composition in sintering furnaces is a strong instrument for the improvement of PM processes.