2-STEP SINTERING OF A TIB2NI CERMET

The effect of atmosphere control on the sintering behaviour of TiB2-20 wt % Ni ceramics was investigated. Sintering was performed at 1700 de grees C for 1 h with commercial TiB2 powders produced by the carbother mic reaction. Under a fixed single atmosphere such as vacuum or Ar, de nsification was limited and large pores remained. However, a sintered density above 99% of theoretical could be achieved by a two-step sinte ring procedure in which the atmosphere was changed from vacuum to Ar a t 1600 degrees C during the heat-up with subsequent isothermal sinteri ng being performed at 1700 degrees C for 1 h. Qualitative consideratio ns about these phenomena are discussed.