Drastic enhancement of mechanical properties of Ca3Co4O9 by B4C addition

Ca3Co4O9 with B4C additions in different proportions (0, 0.10, 0.25, 0.5, and 0.75 wt.%) have been fabricated using the classical solid-state method. Powder XRD patterns displayed that phase is major one all samples. Microstructural observations showed has superficially oxidized, producing liquid B2O3 during sintering, reacting grains to produce bridges between them. In spite of increase porosity, these led an important raise (more than two times) mechanical properties when compared pristine materials. On other hand, while addition not influenced S values, it decreased electrical resistivity, thermal conductivity, expansion. Consequently, ZT values also increased, reaching 0.24 at 800 °C 0.25 wt.% containing samples, which very close best reported literature, times higher obtained pure materials this work.