Alumina Properties

 

Alumina, also termed as Aluminium oxide (Al₂O₃). It is generally white in color or nearly crystalline substance. Alumina is amongst the most cost-effective and commonly utilized material in the family of technical ceramics. The raw materials from which highly efficient technical grade ceramic is manufactured are easily accessible and cheaply priced, resulting in enhanced value for the cost in fabricated alumina structures. So it is no surprise that fine-grain technical grade alumina has a variety of applications due to its significant combination of characteristics and low price. in this article we are going to see about alumina properties as well as its applications.

Properties of Alumina

• Density: 2.95 – 3.98 g/cm³
• Melting point: 2071^oC
• Boiling point: 2947^oC
• Solubility: Insoluble in water, organic solvents, strong alkalis, strong acids, weak acids and weak alkalis
• Molar mass: 101.96 g/mol
• Crystal structure: Trigonal
• Bulk modulus: 137 – 324 Gpa
• Elastic Modulus: 215 – 413 MPa
• Fracture toughness: 3.3 – 5 MPa
• Hardness: 5500 – 22050 MPa
• Modulus of rupture: 152 – 800 MPa
• Tensile strength: 69 – 665 MPa
• Thermal expansion: 4.5 – 10.9 * 10^-6 K
• Thermal conductivity: 12 – 38.5 W/m.K
• Extremely hard material
• It is made of covalent bond, so that it has higher mechanical strength, resistant to corrosion and resistant to wear.
• Chemically stable material
• Good strength as well as high stiffness
• Resistance to strong acids and alkalis even at higher temperature
• Resist attack by all gases except by wet fluorine

Applications of alumina

• Alumina is used as filler in paper and plastic industry, and supporting material due to its high hardness, high fracture toughness and high strength.

• It is used in polymers. If alumina is mix with polymer, it will produce to form PBZ (polymer). By this process, it gives support to polymer.

• It is utilized as fibre composite to improve properties, catalyst in industries and to separate or removal of water from gas steam.

• It is used in the abrasive industry and in the manufacturing of sandpaper owing to its significant properties such as wear and abrasion resistance.

• It is used in inert and oxide atmosphere

• The main application of alumina is that it is used in the medical field due to its biocompatibility property. Due to this property, it is used in replacement of bone to increase the wear resistance and mechanical strength.

• It is used in the painting industry especially to enhance the decorative and reflective effect.

• It is used as a bulletproof jacket to increase the mechanical strength.

• It is used in spark plugs, thermocouple tubers, furnace lining, electronic substrate, sample holder and crucibles, sodium vapor lamp, gas laser tubes.

• It is used where high resistance is required mainly as solid lubricants between the metals and grinding media due to its high wear resistance, high strength and high chemical inertness. During milling, grinding media should not contaminate the raw materials. For this reason, alumina is used for high wear resistance in milling industry.

• It is highly used in the refractory industry because of its high refractoriness, high dimensional stability, high stiffness, and high temperature withstanding properties.

• Metal pipes are not suitable for acids. So, alumina is used due to its high chemical stability, high refractoriness, and no reactivity. 

• It is used in CD and DVD polishing kits.

• In toothpaste, alumina is used as a common ingredient.

• To remove dental stains, alumina is used as a polishing agent used by dentists.

• The typical uses of alumina include seal rings, wear pads, furnace liner tubes, electronic substrates, ballistic armor, high voltage insulators, high-temperature electrical insulators, thermometry sensors, radomes, laser activities, wear components, abrasion-resistant tube, and elbow liners.  

For any material, properties and applications play a major role. In this article, you have learned the basic properties and applications of  Alumina.