High‐Temperature Methods

Abstract

The synthesis of ceramics and intermetallics, especially when starting from oxidic precursors and refractory metals, requires high temperatures. This chapter describes most of the high‐temperature techniques and discusses standard commercially available and self‐constructed furnace types. The use of high‐temperature synthesis techniques readily calls for suitable crucible materials that resist the synthesis conditions. Important parameters for a suitable crucible material are the melting temperature, the oxidation stability, the surface wetting, and the machinability. While solar heating can be used for large‐area materials processing, mirror furnaces are employed for selective heating, for example, crystal growth. Solar furnaces produce powers up to 1000 kW, which is large compared to CO2or Nd‐YAG lasers with powers of 2–5 and 0.5 kW, respectively. The generation of very high temperatures (up to 4000 K) is possible by arc melting, where a plasma volume is heated by an electron beam between two electrodes, similar to the well‐known welding techniques.

Unprecedented Deep-Red Ce3+ Luminescence of the Nitridolithosilicates Li38.7RE3.3Ca5.7[Li2Si30N59]O2F (RE = La, Ce, Y)

“…Starting materials were ground in an agate mortar and then transferred into tantalum crucibles. The crucibles were welded shut using the tungsten inert gas (TIG) welding method . Water-cooling was applied during welding to prevent any chemical reactions.…”