Product Item: Small Capacity High Density & Purity Graphite Crucible Metal Graphite
Feature
1. Spalling resistance
2. Corrosion resistance
3. Mechanical shock resistance
4. Oxidation resistance
5. Higher thermal conductivity
6. No metal inclusion
7. Product reliability
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Apparent porosity (%)
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18~24
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Bulk specific gravity
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1.80~2.10
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Thermal conductivity(°C)
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17~45
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Electric resistance(cm)
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1.5~6x10-3
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Modulus of rupture(kg/cm2)
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70~180
50~135
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Wt.loss by oxidation (%)
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< 1.0
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Thermal expansion(%)
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0.25~0.35
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Fixed carbon (%)
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30~55
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SIC (%)
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32~50
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Both the Budget Graphite and Premium Graphite crucibles are high quality melting crucibles. They can be used at temperatures up to 1600C (3000oF)and are suitable for melting and refining precious metals, base metals, and other products.
Use proper flux, and be sure to preheat the crucible prior to the first use to drive off any residual or accumulated moisture.
Notes regarding pre-treating crucibles for refining. Do they need to be pre-fired with flux to "coat" the inside?
Coating the inside of the crucible probably does not help. If you want to coat the inside of the crucible with borax, go ahead as it probably will not hurt anything. But, the borax is a low melting temperature component so the coating will not form much of a barrier after you start heating things up. And, it may "cost" you one of the fires.
Some people do some refining in assay crucibles. The fire clay used in assay crucibles is not rated for nearly as high of temperatures as graphite or silicon carbide, and this is not really recommended. But, if you have had success doing this, make sure and preheat the crucible before use (as mentioned above).
Preheating can be done by placing the crucible on top of the furnace, or on a hot plate, or by putting them in the furnace and raising the temperature slowly.
If need open new mould, please send us detail specification and design drawing firstly, we'll reply you in 24 hours. Contact email: info@csceramic.com
