Schwarz, V., Scagnetto, F., & Lengauer, W. (2019). Sintering of Ti(C,N)-WC/Mo₂C-(Ta,Nb)C-Co/Ni cermets investigated by CO and N₂ outgassing. Metals, 9(4), Article 427. https://doi.org/10.3390/met9040427
General Materials Science; mass spectrometry; sintering; cermets; titanium carbonitride; metal cutting; Metals and Alloys
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Abstract:
Cermets of the type Ti(C,N)-WC/Mo2C-(Ta,Nb)C-Co/Ni with changing [Mo]/([Mo] + [W])
ratio were subjected to an investigation of outgassing of CO and N2 upon sintering. Quantification
of CO and N2 was performed by gas calibration, measurement of masses 12 (12C), 14 (14N) and 28
(28CO and 28N2), as well as C, N, O analysis of the samples before and after sintering. The formation
of CO occurs at lower temperatures than that of N2, both gases being completely evolved already at
solid-state sintering conditions. If pre-alloyed powders are employed in the starting formulation,
the amount of evolved gases is substantially reduced, because part of the formation of mixed hard
phases is anticipated. Changing binder composition from Co:Ni = 1:1 to 2:1 and 3:1 does not change
the outgassing characteristics, while different batches of nominally the same Ti(C,N) powder can have
significant influence. Mass spectrometry is a most valuable in situ tool for getting insight into the
metallurgical reactions occurring upon sintering. These reactions result in the typical microstructure
and influence the properties of cermets.
