The naturally occurring α-type alumina crystals are called corundum, and they often show different colors due to different impurities. Corundum is generally bluish or yellowish gray, with glass or diamond luster, and its density is 3.9-4.1g/cm3. The hardness is 8.8, second only to diamond and silicon carbide, and it can withstand high temperatures. The corundum sand containing iron oxides is called emery, which is dark gray and dark black. It is often used as abrasive material for making various abrasive papers, grinding wheels, and abrasive stones. It is also used to produce optical instruments and certain metal products.
In the large family of fine alumina, alumina as a grinding and polishing material is roughly divided into two categories: fused corundum (such as white corundum, brown corundum, etc.) and sintered corundum. Sintered corundum is a type of alumina in which aluminum hydroxide and aluminum oxide are converted into α-phase after high-temperature calcination. It is called α-alumina in China, and it is also called high-temperature alumina in the industry.
Specification
item |
impurity content≤(%) |
ΑL2O3≥(%) |
LOI≤ |
α- ΑL2O3
≥(%) |
True Density≥(g/cm3) |
| |
Nα2O |
SiO2 |
Fe2O3 |
|
|
|
|
| AT-A |
0.2 |
0.03 |
0.02 |
99.5 |
0.10 |
94 |
3.94 |
| AT-A |
0.3 |
0.04 |
0.03 |
99.3 |
0.10 |
93 |
3.93 |
| Particle Size (D50μm): it can be adjusted appropriately according to your needs |
FAQ
Q: Are you factory?
A: Yes, we are factory.
Q: How is your quality?
A: We have top grade production equipment and precision measuring instruments and we also have engineers and technicians carry out quality control.
Q: Can you supply free samples?
A: 1kgs free sample is available, but freight charges will be at your account, The charges will be return to you or deduct from your order in the future.
Q: What about the payment?
100% T/T in advance, 30% T/T in advance, the balance 70% against the B/L copy, Irrevocable L/C at sight
Q: The MOQ is?
A: MOQ is usually 1 ton, special products can be coordinuted with each other.
Q: Can I visit your factory?
A: Yes, we welcome you to visit our factory at anytime
Q: How about your delivery time?
A: Usually the shipment is within 15 days after confirming receipt of your payment, some products maybe need longer time.
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