Rare earth can significantly reduce the inclusion quantity of two reasons

(1) the characteristics of rare earth oxides with high melting point, than the major, the proportion of about 2.5 times higher than pure aluminum powders. The greater the proportion of oxide, in the process of let stand, the more you will sink of inclusions, thus the remnants of the inclusions in aluminum liquid quantity the less;
(2) rare earth to join aluminium alloy liquid, liquid aluminum is smooth, does not like other refining agent boiling violently, secondary oxidation in the melting process, thus incorporated into the regenerative oxidation film (Al2O3) few in number. Deoxidization Sic Refractory of rare earth elements than deoxidizer Al, Mg, Ti, trace rare earth can make [O] strip to < 1 x 10-4%. Rare earth desulfurization ability is strong, can generate RES or RE2S3, products mainly depends on the activity of rare earth with sulfur or solubility. Rare earth elements in the fluid of the metal, also can react with O and S at the same time generate RE2O2S type sulfide. Rare earth elements can also with low melting point metal such As P, Sn, As elements combined, generate REP, RESn, REAs compounds. These rare earth compounds have the characteristics of high melting point, the proportion of light, when they are higher than the melting point of metal smelting temperature, can rise of slag. Their tiny particle becomes aluminum heterogeneous nucleation crystallization process, the removal of impurities in aluminum and its alloys. So, rare earth can make aluminum impurities redistribution, bulky compound glomeration, purification and grain boundary, improve the deformation, plastic processing of aluminum and its alloys.