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Crucibles used in Czochralski method Melting gold in a graphite crucible Three crucibles used by Thomas Edison. Crucibles are used in the laboratory to contain chemical compounds when they are heated to extremely high temperatures. Crucibles are available in several sizes and typically come with a correspondingly-sized lid. [20]
It was invented to solve the problem of cubic zirconia's melting-point being too high for even platinum crucibles. In essence, by heating only the center of a volume of cubic zirconia, the material forms its own "crucible" from its cooler outer layers. The term "skull" refers to these outer layers forming a shell enclosing the molten volume.
16th century cupellation furnaces (per Agricola). Cupellation is a refining process in metallurgy in which ores or alloyed metals are treated under very high temperatures and subjected to controlled operations to separate noble metals, like gold and silver, from base metals, like lead, copper, zinc, arsenic, antimony, or bismuth, present in the ore.
When silicon is grown by the Czochralski method, the melt is contained in a silica crucible. During growth, the walls of the crucible dissolve into the melt and Czochralski silicon therefore contains oxygen at a typical concentration of 10 18 cm −3. Oxygen impurities can have beneficial or detrimental effects.
The flux lowers the melting point of the desired compound, analogous to a wet chemistry recrystallization. [1] The flux is molten in a highly stable crucible that does not react with the flux. Metal crucibles, such as platinum , titanium , and niobium are used for the growth of oxide crystals.
Ceramic BN crucible. Hexagonal BN (h-BN) is the most widely used polymorph. It is a good lubricant at both low and high temperatures (up to 900 °C, even in an oxidizing atmosphere). h-BN lubricant is particularly useful when the electrical conductivity or chemical reactivity of graphite (alternative lubricant) would be problematic.