Noun
English Wikipedia has an article on:zone meltingWikipedia
zone melting (uncountable)
(physics, chemistry) A technique used to purify a metal, semiconductor or other solid in which a heating system slowly causes a series of molten zones to traverse the solid, leaving purer material behind it.
For semiconductor use, it is further purified with zone melting or single-crystal extraction from a melt ( Czochralski process ). Source: Internet
The powder can be converted into larger crystals of a certain samarium boride using arc melting or zone melting techniques, relying on the different melting/crystallization temperature of SmB 6 (2580 °C), SmB 4 (about 2300 °C) and SmB 66 (2150 °C). Source: Internet