Thermal de-binding kinetics of injection molded W-8%Ni-2%Cu

The pre-mixed W-8%Ni-2%Cu with 50 vol% AIT binder specimens were fabricated by powder injection molding machine. The injected specimens were solvent de-waxed by dipping in n-heptane. Solvent de-waxed specimens were used to investigate thermal degradation of backbone at different heating rates by the mean of nano-balance coupled with mass spectrometry. The evolved products were captured and analyzed online by TG/MS. The heavy alloy shows catalytic effect on thermal decomposition of backbone binder. To investigate this catalytic effect, different metals feedstock were also analyzed and different mass loss behaviors were obtained. Studies show that tungsten metal has pronounced catalytic effect on backbone decomposition. By the help of degradation mechanism, the kinetic analysis was accomplished. Smooth thermal de-binding temperature–time profile was calculated under rate controlled de-binding conditions. The comparison was made between experiment and prediction in Elnik production furnace.

► TG/MS technique provides sufficient knowledge to understand backbone removal process in heavy alloy.
► Heavy alloy shows catalytic effect on thermal decomposition of binder.
► Tungsten metal has significant effect on backbone pyrolysis which may be caused by finer W.
► The kinetic analysis enables to optimize the thermal de-binding process to avoid sudden decomposition of backbone binder.
► Satisfactory agreement between prediction and experimental run was obtained in production furnace.