A small sealed Ta crucible for thermal analysis of volatile metallic samples

摘要

Differential thermal analysis on metallic alloys containing volatile elementscan be highly problematic. Here we show how measurements can be performed incommercial, small-sample, equipment without modification. This is achieved byusing a sealed Ta crucible, easily fabricated from Ta tubing and sealed in astandard arc furnace. The crucible performance is demonstrated by measurementson a mixture of Mg and MgB$_2$, after heating up to 1470$^{\circ}{\rm C}$. Wealso show data, measured on an alloy with composition Gd$_{40}$Mg$_{60}$, thatclearly shows both the liquidus and a peritectic, and is consistent withpublished phase diagram data.