Pink aluminium oxide, often referred to as Pink Fused Alumina (PFA), is a popular synthetic material known for its hardness and durability. This material is widely used in a variety of applications ranging from abrasive blasting, grinding, lapping, and more.
Pink Aluminium Oxide Parameters
- Hardness: Approximately 9 on the Mohs scale.
- Grain Size: Varies from coarse (12-24 grit) for aggressive material removal, to fine (80-220 grit) for precision applications.
- Density: Approximately 3.96 g/cm³, heavier than many other abrasives.
- Melting Point: Over 2000°C, capable of withstanding extremely high temperatures.
- Crystal Structure: Trigonal crystal structure, contributing to its hardness and durability.
- Chemical Stability: Resistant to most acids and alkalis, suitable for use in a variety of chemical environments.
Manufacturing Process of Pink Aluminium Oxide
The production of Pink Aluminium Oxide involves the fusion of calcined alumina and chromium oxide under high temperatures in an electric arc furnace. This process produces a material with increased toughness and hardness compared to white aluminium oxide.
- Calcining Alumina: Alumina, derived from bauxite, is calcined at temperatures above 1000°C to eliminate impurities and water content.
- Fusion with Chromium Oxide: The calcined alumina is then mixed with chromium oxide and subjected to intense heat in an electric arc furnace. This results in the formation of Pink Aluminium Oxide.
- Cooling and Crushing: The molten Pink Aluminium Oxide is cooled and then crushed into the desired grain sizes. The crushed material is then screened for quality assurance.
Applications of Pink Aluminium Oxide
Pink Aluminium Oxide, given its high hardness and toughness, finds numerous applications across various industries. Here are some of the key applications:
- Abrasive Blasting: Pink Aluminium Oxide’s hardness and sharpness make it highly effective in abrasive blasting applications, where it is used for surface preparation, cleaning, and etching. Its toughness allows it to be reused multiple times, making it a cost-effective choice.
- Grinding Wheels: The material’s hardness and durability make it an excellent choice for the manufacture of grinding wheels and other abrasive tools. These are used for cutting, grinding, and polishing metal and other hard materials.
- Lapping and Polishing: The fine grains of Pink Aluminium Oxide are particularly suitable for precision lapping and polishing applications. These are used in industries like electronics and optics, where they help achieve smooth and precise finishes on various materials.
- Refractories and Ceramics: Due to its high melting point and thermal stability, Pink Aluminium Oxide is used in the manufacturing of refractory materials, which are materials capable of withstanding extremely high temperatures without losing their strength or shape. It is also used in the ceramics industry for similar reasons.
- Coated Abrasives: Pink Aluminium Oxide is used as the abrasive grain in many coated abrasives, such as sandpaper and abrasive belts. Its hardness makes it effective for sanding and finishing operations.
- Anti-Skid Applications: In certain cases, Pink Aluminium Oxide is also used in anti-skid applications due to its hardness and abrasive nature. It can be added to surfaces to increase traction and prevent slipping.
Please note that the specific use of Pink Aluminium Oxide can depend on its specific parameters, such as grain size and hardness. Different applications may require different specifications of Pink Aluminium Oxide.
Comparing Aluminium Oxides: White, Brown, Black, and Pink
Aluminium oxides come in several varieties, each with unique properties that make them suitable for different applications. The most common types are white, brown, black, and pink aluminium oxide. This section will compare and contrast these materials.
1. White Aluminium Oxide
White Aluminium Oxide (WA) is a high-purity synthetic abrasive made from reduced fusion of high-quality alumina powder. It is characterized by its self-sharpening and high cutting power. The hardness of WA is slightly higher than brown aluminium oxide, but its toughness is lower.
- Hardness: High, slightly higher than brown aluminium oxide.
- Toughness: Lower than brown aluminium oxide.
- Applications: Precision grinding, surface finishing, and cutting tools.
2. Brown Aluminium Oxide
Brown Aluminium Oxide (BA), often known as fused alumina, is made by reducing bauxite in an electric arc furnace. It is a hard and tough material used in manufacturing of grinding wheels (both vitrified and resin bonded) and coated products.
- Hardness: High, slightly lower than white aluminium oxide.
- Toughness: High, higher than white aluminium oxide.
- Applications: Resin-bonded and vitrified-bonded grinding wheels, blasting media, metal preparation.
3. Black Aluminium Oxide
Black Aluminium Oxide is a durable, sharp abrasive that features a lower Al2O3 content compared to brown and white aluminium oxides. It has lower purity and higher toughness, making it perfect for certain rougher applications.
- Hardness: High, but generally lower than both brown and white aluminium oxide.
- Toughness: High, higher than white aluminium oxide, comparable to brown aluminium oxide.
- Applications: Abrasive blasting, floor and non-skid applications, and rock tumbling.
4. Pink Aluminium Oxide
As discussed earlier, Pink Aluminium Oxide (PFA) is made from the fusion of calcined alumina and chromium oxide. It is known for its exceptional hardness and durability, surpassing white aluminium oxide. Its high toughness is due to the presence of chromium oxide.
- Hardness: Exceptionally high, surpassing white, brown, and black aluminium oxide.
- Toughness: High, due to the presence of chromium oxide.
- Applications: Abrasive blasting, grinding wheels, lapping, and polishing.
In conclusion, each type of aluminium oxide has its unique properties and applications. While white and pink aluminium oxides are known for their high hardness, brown and black aluminium oxides are recognized for their high toughness. Choosing the right type of aluminium oxide depends largely on the specific requirements of the application.