| Chemical & Physical Properties |
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Crystal Form
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Alpha alumina trigonal system
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Chemical nature
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Amphoteric
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Reaction with acids
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Attck less than brown fused alumina
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Reaction with Alkalies
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Very slight with strong hot solution only
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Oxidation-reduction effects
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None
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True Density (g/cm3)
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3.96
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Hardness
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Knoop (kg/cm2)
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2000-2200
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Moh's
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9.0
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Color
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White
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Color after firing
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White
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Melting point
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2000oC
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Max usable temperature
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1900oC
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Specific heat (cal/g.oC )
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20oC
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100oC
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0.183
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0.217
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Coefficient of thermal conductivity (cal/cm2.secoC)
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Room temperature
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900oC
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0.047
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0.013
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Electrical resistivity (Wcm)
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30oC
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300oC
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900o C
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1600oC
|
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1016
|
1013
|
105
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104
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Coefficient of liner expansion (x10-6)
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25oC-500oC
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25oC-1000oC |
25oC-1500oC
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7.58
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8.52
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9.29
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| Chemical Composition |
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Grit
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12# - 90#
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100# - 220#
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230# - 400#
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500# - 1200#
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Al2O3
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98.5 min
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98.5 min
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98.0 min
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97.0 min
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0.5 max |
0.7 max |
0.8max |
0.8max |
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| Magnetic Material Content (% by weight) |
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Grit
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Magnetic Material Content
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16#-24#
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<0.0023
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30#-120#
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<0.0021
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150#-240#
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<0.0015
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| Available grain sizes |
| Grit No. |
Micron |
Grit No. |
Micron |
Grit No. |
Micron |
| 10 |
2360 ~ 2000 |
30 |
710 ~ 600 |
80 |
212 ~ 180 |
| 12 |
2000 ~ 1700 |
36 |
600 ~ 500 |
90 |
180 ~ 150 |
| 14 |
1700 ~ 1400 |
40 |
500 ~ 425 |
100 |
150 ~ 125 |
| 16 |
1400 ~ 1180 |
46 |
425 ~ 355 |
120 |
125 ~ 106 |
| 20 |
1180 ~ 1000 |
54 |
355 ~ 300 |
150 |
106 ~ 75 |
| 22 |
1000 ~ 850 |
60 |
300 ~ 250 |
180 |
90 ~ 63 |
| 24 |
850 ~ 710 |
70 |
250 ~ 212 |
220 |
75 ~ 53 |
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Standard werte der Mikro-F-Reihe
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