
1. Description
Al2O3 is an electrical insulator but has a relatively high thermal conductivity (30 Wm−1K−1) for a ceramic material. Aluminium oxide is insoluble in water. In its most commonly occurring crystalline form, called corundum or α-aluminium oxide, its hardness makes it suitable for use as an abrasive and as a component in cutting tools.
Aluminium oxide is responsible for the resistance of metallic aluminium to weathering. Metallic aluminium is very reactive with atmospheric oxygen, and a thin passivation layer of aluminium oxide (4 nm thickness) forms on any exposed aluminium surface. This layer protects the metal from further oxidation. The thickness and properties of this oxide layer can be enhanced using a process called anodising. A number of alloys, such as aluminium bronzes, exploit this property by including a proportion of aluminium in the alloy to enhance corrosion resistance. The aluminium oxide generated by anodising is typically amorphous, but discharge assisted oxidation processes such as plasma electrolytic oxidation result in a significant proportion of crystalline aluminium oxide in the coating, enhancing its hardness.
Aluminium oxide was taken off the United States Environmental Protection Agency's chemicals lists in 1988. Aluminium oxide is on EPA's Toxics Release Inventory list if it is a fibrous form.
The applications for alumina advanced ceramics are heavy-duty forming tools, substrates and resistor cores in the electronics industry, tiles for wear protection and ballistics, thread guides in textile engineering, seal and regulator discs for valves, heat-sinks for lighting systems, protection tubes in thermal processes or catalyst carriers for the chemicals industry.
2. Technical Property
Property | Units | ||||
Al2O3 Content | % | 96 | 98 | 99.5 | 99.7 |
Density | g / cm3 | 3.70 | 3.80 | 3.90 | 3.92 |
Color | - | White | White | Ivory | Ivory |
Compressive Strength @ 25 C | Mpa | 2229 | 2091 | 2512 | 2350 |
Tensile Strength @ 25 C | MPa | 200 | 200 | 248 | 252 |
Flexural Strength @ 25 C | MPa | 331 | 276 | 324 | 320 |
Elastic Modulus @ 25 C | GPa | 290 | 331 | 366 | 380 |
Hardness : Knoop Rockwell | (Gpa) Kg/mm2 R45N | (11.7) 1196 79 | (12.5) 1276 77 | (14) 1428 85 | (15) 1510 90 |
Thermal Conductivity @ 25 C | W / m-Deg K | 20.8 | 28.1 | 30.7 | 31.6 |
Coefficient of Thermal Expansion @ 25-1000 C | 1 X 10-6 / Deg C | 7.9 | 8.5 | 8.1 | 8.0 |
Specific Heat @ 25 C | cal / g / Deg C | .184 | .184 | .182 | .180 |
Maximum Working Temp. | Deg C | 1650 | 1650 | 1700 | 1700 |
VolumeResitivity @25C @700 C | ohm-cm ohm-cm | 1 X 10-13 1 X 10-8 | 1X 10-13 2.2 X 10-9 | 1 X 10-13 6 x 10-7 | 1 X 10-13 6 x 10-7 |
Dielectric Strength (@Thickness) 100Mils | ac volts per mil | 350 | 340 | 335 | 330 |
Dielectric Constant 1Mhz @25C | e' / eo | 8.6 | 9.4 | 9.7 | 10.0 |
Dissipation Factor 1 Mhz @25C | Tan Delta | .0004 | .0003 | .0003 | .0002 |
Yixing City Kam Tai Refractories Co.,ltd
Yixing City Kam Tai Refractories Co.,ltd is located in Yixing, the
Pottery capital of China. Our company is founded in 2006, it is a
professional refractory and ceramic company which cover research,
production, sales and after-sales service. Since establishment, we
adhere to principle of “Technological Innovation, Never Stop”,
continuously improve R&D and production process and equipment.
Moreover, we cooperate with famous university such like Liaoning
University of Science and Technology, Beijing University of Science
and Technology.
Main Products
We mainly manufacture industry furnace refractory material such as
Sic PLATE,Setter plate, Push plate, Pillar,Sagger, Technical
Ceramic, Furnace material and so on. Our product is widely used to
sinter Magnetic Material, Electronic Ceramic, Daily Ceramic, Powder
Metallurgy, Rare Earth Battery Material and so on. Our sandwich
setter plate, electronic ceramic used sagger, Lithium battery
cathode material sintering sagger are very good , and they have
been leader products in our field .
Company Vision
Since our establishment, we insist on “No best , Just Better” , aimed to be the top Supplier of Refractory material and Technical Ceramic in the world.