A mechanism for low-temperature sintering

We explain the basic mechanism of the low-temperature sintering called reactive liquid-phase sintering. The mechanism involves the presence of a low-temperature liquid phase that must be able to directly or indirectly accelerate a reaction with the matrix phase. The mechanism is explained in details for the case of the low-temperature sintering of BaTiO3, which was sintered to more than 95% of relative density in 15 min at 820 °C. We have applied reactive liquid-phase sintering to a number of different compounds with very different crystal-chemistry characteristics, and managed to sinter them as much as 400 °C below their original sintering temperatures. A thorough understanding of this sintering mechanism makes it possible to closely control the sintering behavior.