Effect of rare-earth chromites on sintering of magnesia

The effect of neodymium, cerium, lanthanum, and yttrium chromites, added in amounts of not more than 8%, on the sintering of magnesia in air and in vacuum has been studied. On addition of rare-earth chromites, the initial magnesia is sintered to a density of 0.98. By their sintering action, these chromites fall into the following sequence: neodymium chromite — lanthanum chromite — yttrium chromite — cerium chromite. The highest density (0.98 – 0.99) and the lowest porosity (1–2%) are obtained on addition of 2% of neodymium chromite to magnesia. The process of sintering of magnesia is accompanied by an increase in the size of periclase crystals from 12 to 38–56 µm.Translated from Ogneupory, No. 1, pp. 2–4, January, 1994.