Lanthanum carbide-based porous materials from carburization of lanthanum oxide and lanthanum oxalate mixtures

Porous lanthanum carbide (LaC2) based materials were prepared from lanthanum oxalate (La-2(C2O4)(3)), lanthanum oxide (La2O3) and graphite mixtures. The molar ratio between La2O3 and La-2(C2O4)(3) was varied in order to detect the effect of starting mixtures on the porosity of the products. Samples structure and morphology were investigated by means of scanning electron microscopy, equipped with the probe for elemental analysis, (SEM-EDS) and X-ray diffraction spectrometry (XRD). As for the porosity characterization, the amount of total porosity was derived from the comparison between the theoretical and the measured density values, whereas a thorough investigation on the amount of open porosity and pore size distribution was carried out by means of Mercury Intrusion Porosimetry, after carburization and sintering. Emissivity measurements were performed upon carburization and sintering in order to verify the effect of porosity on emissivity values. (C) 2008 Elsevier B.V. All rights reserved.