About Alumina Ceramics

Alumina ceramics is the most common advanced ceramic material, and it is also a relatively traditional ceramic material. As an excellent ceramic material, high-purity alumina ceramics has been widely used in many industries. The material has excellent properties in terms of electrical insulation, high thermal conductivity, high chemical resistance, good wear resistance and low thermal expansion.
Alumina ceramics can be divided into multiple application grades according to their alumina content. Among them, 99% alumina ceramic materials are used to make high-temperature crucibles, refractory furnace tubes and special wear-resistant materials(such as ceramic bearings, ceramic seals, and water valve discs.); 95%-96% alumina porcelain is mainly used for corrosion-resistant, wear-resistant parts and circuit substrates.

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Our alumina ceramic services:

Great Ceramic is an expert in the production of technical ceramics. Since 2013, we have participated in and provided more than 3,000 types of precision ceramic products to hundreds of companies.
We can provide you with ceramic processing, ceramic raw materials, ceramic mold forming, surface metallization and other services, and we are committed to providing only products and services that meet or exceed customer quality requirements.

 

Machining

Materials

Mould

Metallization

Glazing

 

Available Grades Of Alumina

  • 95%-99.7%  high purity Alumina
  • High purity re-crystalized Alumina
  • Zirconia Toughened Alumina (ZTA)

Alumina Ceramic Products:

 

Why use alumina ceramics?

  • Relatively low density;
  • Extremely high operating temperature;
  • Very high hardness and compressive strength;
  • Excellent electrical insulation properties;
  • Corrosion and wear resistance;
  • Biologically inert, food compatibility。

Mechanical Properties

Properties Unit 95%Al2O3 99%Al2O3 99.5%Al2O3
Colour —— White Yellow Yellow
Density g/cm³ 3.7 3.85 3.9
Hardness GPa 13.7 15.2 15.7
Compressive Strength MPa 2000 2160 2350
Flexural Strength MPa 280 310 350
Fracture Toughness MPa・m1/2 3~4 3~4 4.5
Modulus of Elasticity GPa 320 360 370
Poissons Ratio —— 0.23 0.23 0.23

Thermal Properties

Properties Unit 95%Al2O3 99%Al2O3 99.5%Al2O3
Maximum Use Temperature ℃(No load) 1650 1650 1650
Thermal Conductivity @ 20°C W/(m・K) 24 29 32
Thermal Expansion a at 20–400°C 1 x 10-6/°C 7~8 7~8 7~8
Specific Heat J/(kg・K) 780 790 780
Thermal Shock Resistance ℃(Put in water) 200 200 200

Electrical Properties

Properties Unit 95%Al2O3 99%Al2O3 99.5%Al2O3
Dielectric Constant 1MHz 9.4 9.9 9.9
Dielectric Strength V/m 15 x 106 15 x 106 15 x 106
Dielectric Loss 1MHz 4 x 10-4 4 x 10-4 4 x 10-4
Volume Resistivity @ 25°C Ω・cm >1014 >1014 >1014
Volume Resistivity @ 500°C Ω・cm >108 >108 >1010

*The values are typical material properties and may vary according to products configuration and manufacturing process. For more details, Please feel free to contact us.

 

What can alumina ceramics be used for?

  • Wire and thread guides
  • Mechanical seals
    • Seal faces
    • Valve seats
  • Machine components
  • High temperature electrical insulators
  • High voltage insulators
  • Electronic components & substrates
  • Ballistic Armor
  • Roller & Ball Bearings
  • Wear resistant linings
  • Semiconductor parts
  • Laser cavities
  • Tap plates
  • Shot blast nozzles
  • Knife Sharpeners
  • Precision shafts and axles in high wear environments

Processing Of Alumina Ceramics

 

Alumina can be processed in green or fully dense state. In the green state, it can be processed into complex geometry relatively easily.However, the sintering process that is required to fully densify the material causes the alumiuna body to shrink approximately 20%. This shrinkage means that it is impossible to hold very tight tolerances when machining alumina pre-sintering. In order to achieve very tight tolerances, fully sintered material must be machined/ground with diamond tools.  In this process a very precise diamond coated tool/wheel is used to abrade away the material until the desired form is created. Due to the inherit toughness and hardness of the material, this can be a time consuming and costly process.

 

Alumina Ceramics Custom Processing

 

Great Ceramic is your Alumina machining specialist for your precision ceramic prototyping & manufacturing needs; we are always happy to use our many years of advanced ceramics experience to provide advice on materials, design, and application. If you would like to buy Alumina plates, rods, tubes or custom machined components, please contact us and one of our experts will be happy to assist you.