Gas Athmosphere Analyses during Debinding and Sintering of Powder Injection Molding Components

Sintering is the major cost factor in Powder Injection Molding. Companies are interested in reducing the cost while keeping on improving quality of sintering. It is well known that the atmosphere surrounding the samples in the furnace has pronounced effects on the sintered parts and thereby, know-how about it may allow streamlining the process. In this study, gas atmosphere analyses were carried out in order to identify the gas species created during debinding and sintering of PIM components. The intervals of occurrence and the thermochemical reactions leading to the degassed substances were determined, while varying powder, binder and process gas. The experiments were carried out with a mass spectrometer connected on-line to an industrial batch PIM furnace. Powder and process gas had a clear effect on the outgassing and final properties of the sintered parts. On the other hand, the exact nature of binder decomposition was not easily identified via mass spectrometry. It was found that methane production controls the final carbon content of the sintered parts and that this can be influenced by powder, gas atmosphere and sintering program. In general, mass spectrometry allowed learning much about sintering and will certainly help to improve processing of PIM parts in batch and continuous furnaces.