Crucibles serve both the scientific and industrial sectors by melting or otherwise processing materials at very high temperatures. So, crucibles themselves are constructed from materials with extremely high melting points, like alumina or silicon carbide. There are also quartz crucibles and ceramic crucibles. The ones used in laboratories are much smaller than the industrial varieties used for large scale metal processing.

Besides the distinction between the low profile, wide opening shapes of wide (or low) form crucibles and the tall, often tapering shapes of high (or tall) form crucibles, there are three typical designs:

1. Barrel-shaped crucibles, which are wider in the middle than at the opening or base.

2. Conical crucibles, which have wider openings than bases.

3. Cylindrical crucibles, which either have a consistent diameter from top to bottom or a slight outward taper from top to bottom.

Action Steps
The best contacts and resources to help you get it done

Buy a crucible with the right specifications

Pay attention to the inner atmosphere type of a crucible, which may simply be air, or it may be inert gas or a vacuum. The eating method also makes a big difference. Some of the many options include electron beam, plasma arc or the simple gas-fired furnace. There are also induction, evaporator and other types. The most important thing to keep in mind, however, is your particular application. There are industrial crucibles for metal casting, and there are industrial crucibles for smelting gold. Then there are laboratory crucibles, which are altogether different.

I recommend: For a huge selection of electron beam crucibles, take a look at International Advanced Materials. They will manufacture for nearly any specs. Zircoa sells alumina crucibles for induction melting at low rates. They offer products suitable for vacuum or oxidizing atmospheres.

Locate crucible suppliers that carry industrial crucibles made of your preferred material

As already mentioned, there are quartz, silicon carbide and alumina industrial crucibles. However, there are also graphite crucibles. Also, there's the copper crucible, which is usually cooled with water or salt.

I recommend: Zak Incorporated carries large copper crucibles, in addition to hearths and molds. For smaller applications, check out GraphiteStore.com. They have crucibles smaller than a foot in diameter, all the way down to 4 inches.

Purchase a laboratory crucible

Applications for lab crucibles are quite different than those for industrial settings. Common applications include chemical analysis and detection of ash content. Laboratory crucibles are commonly made from ceramics or porcelains, quartz, glass and clay.

I recommend: Technical Glass Products, Inc. carries low-form glass and quartz-fused crucibles with anywhere from 10 to 100 cc capacities. Alternatively, Quartz Scientific, Inc. carries both low and tall form crucibles.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  If you want to avoid oxidization and scaling, a ceramic crucible is a good option.