High quality alpha/gamma aluminum oxide powder,al2o3 powder,China Baorui price supplier

 

Aluminium oxide is an electrical insulator but has relatively high thermal conductivity (35 W/m K).In its most commonly occurring crystalline form, called corundum or a-aluminium oxide, its hardness makes it suitable for use as an abrasive and as a component in cutting tools.

 

Aluminium oxide is responsible for metallic aluminium's resistance to weathering.Metallic aluminium is very reactive with atmospheric oxygen, and a thin passivation layer of alumina quickly 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 alumina generated by anodising is typically amorphous, but discharge assisted oxidation processes such as plasma electrolytic oxidation result in a significant proportion of crystalline alumina in the coating, enhancing its hardness.

 

Alumina's combination of hardness, high temperature operation and good electrical insulation makes it useful for a wide range of applications.Alumina is the most commonly used type of ceramic and is available in purities up to 99.99%.

 

Different types aluminium oxide ceramics:

 

- 94% min Al2O3

- 96% min Al2O3

- 97% min Al2O3

- 99% min Al2O3

- Single Crystal Alumina:Synthetic Ruby, Synthetic Sapphire

- Other:ZTA, Zr, others upon request

 

Applications:

 

High Temperature and Aggressive Environments

Its high free energy of formation makes alumina chemically stable and refractory, and hence it finds uses in containment of aggressive and high temperature environments.

 

Wear and Corrosion Resistance

The high hardness of alumina imparts wear and abrasion resistance and hence it is used in diverse applications such as wear resistant linings for pipes and vessels, pump and faucet seals, thread and wire guides etc.

 

Biomedical

High purity aluminas are also used as orthopaedic implants particularly in hip replacement surgery.

 

Metal Cutting Tools

The high "hot" hardness of alumina have led to applications as tool tips for metal cutting (though in this instance alumina matrix composites with even higher properties are more common) and abrasives.

 

Milling Media

Alumina is used as milling media in a wide range of particle size reduction processes.

 

Microwave Components

The high dielectric constant coupled with low dielectric loss particularly at high frequencies leads to a number of microwave applications including windows for high power devices and waveguides.

 

Electrical Insulation

The high volume resistivity and dielectric strength make alumina an excellent electrical insulator which leads to applications in electronics as substrates and connectors, and in lower duty applications such as insulators for automotive spark plugs

 

Characteristics	Unit	95 Al2O3	99 Al2O3	ZrO2	GPSi3N4	BN	Glass Ceramic
Crystal Structure	-	hexagonal	hexagonal	tetragonal	hexagonal	hexagonal	-
Color	-	white	ivory	white	gray	white	white
Density	g/cm³	3.65	3.88	5.95	3.22	2.26	2.55
Water Absorption	%	0	0	0	0	0.0-1.0	0
Young's Modulus	Gpa	280	350	205	295	670	65
Vickers Hardness	Gpa	14	20	12	18-20	-	-
Flexural Strength	Mpa	280	300	900	650	51	100
Compressive Strength	Mpa	2000	2500	2200	2200	23	500
Thermal Conductivity	W/(m•K)	18-25	30	2.2	25	20	1.70
Thermal shock resistance	ΔT(C°)	220	180-200	280-350	450-650	>1500	25-100
Max. Working Temperature	C°	1500	1700	850	1200	960	800
Volume Resistivity	Ω . cm	>10^15	>10^14	>10^12	>10^14	10^13	10^16
Dielectric Constant	-	9.50	9.80	26	8.20	4.08	6.02
Dielectric Strength	kV/mm	16	22	-	16	375	40