Brown Fused Aluminum Oxide
| Chemical & Physical Properties | ||||||
| Crystal Form | Alpha alumina trigonal system | |||||
| Chemical nature | Amphoteric | |||||
| Reaction with acids | Subject to mild attack by aqua and/or hydrofluoric acid | |||||
| Reaction with Alkalies | Very slight with strong hot solution only | |||||
| Oxidation-reduction effects | None | |||||
| True Density(g/cm3) | 3.97 | |||||
| Hardness | Knoop(kg/cm2) | 2000-2200 | ||||
| Moh's | 9.0 | |||||
| Color | Dark Brown | |||||
| Color after firing | Light blue | |||||
| Melting point | 2000°C | |||||
| Max Usable temperature | 1900°C | |||||
| Specific heat (cal/g.°C) | 0.26(20-29°C) | |||||
| Coefficient of thermal conductivity (cal/cm2.sec.°C) | Room temperature | 900°C | ||||
| 0.047 | 0.013 | |||||
| Electrical resistivity (Wcm) | 30°C | 300°C | 900°C | 1600°C | ||
| 1016 | 1013 | 105 | 104 | |||
| Coefficient of liner expansion (x10-6) | 7-9(0-1600°C) | |||||
| Chemical Composition (% by weight) | |||||
| Grit Item | 10 - 90 | 100 - 180 | 220 - 220 | 230-400 | 500-1200 |
| Al2O3 | 94.5 - 97.0 | 93.5 min | 92.5 min | 91.0 min | 89.0 min |
| TiO2 | 1.5 - 3.8 | 1.5 - 3.8 | 1.5 - 3.8 | 4.0 max | 4.0 max |
| Magnetic Matters Contents (% by weight) | |
| Grit No. | Magnetic Matters Content |
| 16#-30 | <0.0380 |
| 36#-60# | <0.0280 |
| 70-120# | <0.0230 |
| 150#-220# | <0.0170 |
| 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 |
| Available mircron powder sizes | ||||||||
| China GB 2477-83 | JIS | FEPA(84) / DIN(70) | ISO(77) | |||||
| Grit No. | Norminal size range (µm) | Grit No. | ds50 value (µm) | Grit No. | ds50 value (µm) | Grit No. | ds50 value (µm) | |
| Standard werte der Mikro-F-Reihe | Sedigraph 5000D | |||||||
| 240 | 60.0±4.0 | P240 | 58.5±2.0 | |||||
| 280 | 52.0±3.0 | P280 | 52.2±2.0 | |||||
| W63 | 63 - 50 | 320 | 46.0±2.5 | F230/53 | 53±3.0 | 50.0±3.0 | P320 | 46.2±1.5 |
| W50 | 50 - 40 | 360 | 40.0±2.0 | F240/45 | 44.5±2.0 | 42.0±2.0 | P360 | 40.5±1.5 |
| 400 | 34.0±2.0 | P400 | 35.0±1.5 | |||||
| W40 | 40 - 28 | 500 | 28.0±2.0 | F280/37 | 36.5±1.5 | 34.5±1.5 | P500 | 30.2±1.5 |
| 600 | 24.0±1.5 | F320/29 | 29.2±1.5 | 27.7±1.5 | P600 | 25.8±1.0 | ||
| W28 | 38 - 20 | 700 | 21.0±1.3 | F360/23 | 22.8±1.5 | 21.6±1.5 | P800 | 21.8±1.0 |
| Brown Fused Alumina Refractories (% by weight) | |||
| Group Sizes of BFA | Mixed Sizes of BFA | ||
| Sizes (mm) | Chemical Content | Sizes (mm) | Chemical Content |
| 8-5 5-3 | |||