Impurity Characterization by LA-ICP-MS in Terbium Metal after Solid State Electrotransport Purification

Abstract

Terbium metal rod with the dimension of 6.8mm in diameter and 150mm in length has been purified by solid state electrotransport (SSE) at 1050°C under a pressure of 10-5Pa for 50h, and the impurity distribution has been determined by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The research results indicate that, the rare earth impurity migrates from cathode to anode of the rod, and the impurity distribution is relatively uniform in the longitudinal section; low melting point impurity of Al migrates from cathode to anode and the impurity concentration distribution is relatively uniform in the longitudinal section, the segregation degree is about 10% in each sample; the impurity with high melting point, Ta, W, Mo, etc., the distribution of above impurity is very non-uniform, for the impurity of Ta, the mean concentration of sample 7 is only 8.75 ppm, but the local concentration is up to 350 ppm, and it exists in an elementary substance form in the Tb; non-rare earth impurity in Tb metal, such as Ni, Si and Ti, migrates from cathode to anode of the rod significantly; the total impurity content in cathode end is lower than other posion, the impurty content of 22 imputies in sample 6 is 648.47 ppm, is the lowest in the Tb rod, except for the high melting point impurities, the lowest impurity content is 60.05ppm in sample 7.