Why does the graphite crucible used for molten gold add a quartz coat?
The melting point of gold is 1063 degrees Celsius. At this temperature, graphite reacts with oxygen in the air to produce carbon dioxide. The quartz coat may be used to prevent leakage of graphite crucibles
Graphite crucible is afraid of high temperature, but high temperature oxidation, Shi Huang coat is not oxidized to protect the crucible.
