Alumina is one of the most widely specified, general-purpose technical ceramics.
All aluminas are very hard and wear resistant, with high compressive strength even
against extreme temperatures and corrosive environments. Aluminas are also excellent
electrical insulators and are gas tight.
Commercially available grades range from 92% up to 99.95% with the higher purity
generating higher hardness. It is possible to machine alumina using diamond grinding
techniques. Polishing is also possible, with the degree attainable affected by alumina
grain size and production technique.

Properties of Alumina/Aluminum Oxide (Al2O3)
 Very good electrical insulation
 Construction material
 Moderate to extremely high mechanical strength
 Very high compressive strength
 High hardness
 Moderate thermal conductivity
 High corrosion and wear resistance
 Good gliding properties
 Operating temperature without mechanical load 1,000 to 1,500°C.
 Bioinert and food compatible
 Acids resistance
Advantages of alumina ceramics
High mechanical strength;
High resistivity;
Good electrical insulation performance;
High hardness;
Resistant to acids;

The density of alumina ceramics is 3.6g/cm3, which is only half of the density of the
steel, which can greatly reduce the equipment load;
High melting point, anti-corrosion, melting point 2050℃, can resist the erosion of molten
metals such as Be, Sr, Ni, Al, V, Ta, Mn, Fe, Co. It also has high resistance to erosion of
NaOH, glass and slag;
Alumina ceramics have excellent chemical stability, and do not chemically react with
many complex sulfides, such as phosphides, arsenides, chlorides, nitrides, bromides,
iodides, oxides, sulfuric acid, hydrochloric acid, nitric acid, and hydrofluoric acid.

Typical alumina applications include:

 Seal rings
 Blood seals and valve
 Ballistic armour
 Threadguides
 Wear components

Zirconia (Zro2) ceramic offers a combination of high hardness, wear and corrosion
resistance, while exhibiting one of the highest fracture toughness values among all
ceramic materials.

General Properties
 Use temperatures up to 1500°C
 Sintered to full density for a pore free structure
 No compromise between bending strength, hardness and fracture toughness
 Remarkably high fracture toughness and impact resistance while maintaining
above average values for bending strength and hardness
 Toughening by crack deflection provided by a unique microstructure in a partially
stabilised zirconia matrix

Applications of Zirconia
Zirconia is used in applications typically in the metal forming industry
As the material, zirconia is wear resistant and inert and can therefore be utilised in areas
where traditional metallic systems would not be able to function. In sub-sea systems
where metallic systems would corrode, zirconia excels.
Zirconia is used as an oxygen sensor due to the free charge carriers within the structure.
Specific grades of zirconia can become electrically conducting at high temperatures due
to the energy imputed into the material which liberates the charge carriers to carry the
current.
Zirconia has great wear resistance, which combined with the high fracture toughness
properties makes it an ideal material for pumps.