Fe-Ni-Al mixtures as hot-pressing sintering additive to Titanium diboride (TiB2) were studied. It is found that liquid alloy formed under high temperature hardly has effects on the densification behaviors of TiB2-independent. Fe-Ni-Al additive just works as filler between TiB2 particles and does not change the TiB2-independent sintering behaviors. Pressing mode has a great effect on the liquid flowing between TiB2 particles. Multiple-steps pressing mode will give more time and space for the liquid flowing and improve the relative density of TiB2-Fe-Ni-Al cermet.
An ultra-fast densification method based on high heating rate from the combustion reaction for producing carbon nanotubes(CNTs) reinforced alumina ceramics is reported.The heat generated by combustion reaction is adopted to act as a high temperature source to the sample,which results in a heating rate of 1660°C/min of the sample.Then a great mechanical pressure is applied to the sample when the sample gets the expected temperature.The densification process is finished in several minutes.The results indicate that the densification method is beneficial to protect the CNTs from destruction and creates good interfacial combination between the nanotubes and the matrix.With the addition of 1 wt% CNTs,the fracture toughness of the ceramics prepared increases about 50%.
