Samarium impurity systems

Lundin (1970), in an investigation of the formation of samarium-type structure in intra rare earth binary alloys included six compositions in the lanthanum-scandium system ranging from 10 to 85at% La. Lundin prepared his alloys using 99.8(wt )% pure lanthanum metal (major impurities, 330 ppm other rare earths, 510 ppm O, 50 ppm each Si, Mg and Zn) and 99 -F (wt )% pure scandium for which there were no details given on the impurities. Lundin found two-phase inuniscibility at low temperatures in the lanthanum-scandium system and, since no samarium-type structure was found, he concluded that scandium behaves more like the neighboring transition elements than it does as a rare earth metal. 

The samarium and gadolinium metals were reported to include no more than 0.1 wt% total impurities in either metal, but a detailed chemical analysis was not reported. Alloys were prepared by standard arc-melting techniques, and since samarium has a high vapor pressure, the alloys were analyzed by X-ray fluorescence to assess loss of samarium. Loss of gadolinium was not a problem in the alloy preparation since the vapor pressure of gadoUnium is at least four orders of magnitude less than that of samarium. The phase relations in this system were established by metallography. X-ray diffraction, thermal analysis, density and microhardness measurements and effusion experiments. 

---