Brown Fused Alumina
Brown Fused Alumina
Brown fused alumina is an abrasive material that can be used for a variety of different applications. It is made from a mineral called alumina (also known as corundum or aluminum oxide). Alumina is a strong, hard, sharp abrasive that is commonly used for grinding and refractory applications.
Alumina, or alumina oxide (Al2O3), is one of the hardest materials on the Mohs scale. It is also a versatile abrasive that can be used in a variety of different applications, including bonded abrasives, coated abrasives, blasting media, refractory, and metal preparation.
It is produced by the fusion of bauxite ore in electric arc furnaces at a temperature of approximately 2000 degrees Celsius. This fusion process yields blocky crystals that are extremely tough and durable, making it an excellent choice for refractory and abrasive applications.
Fused alumina has an extensive application range and is available in many different grain sizes and chemical purity grades. It is typically used in bonded abrasive applications, but it can also be used for grinding and lapping.
Washington Mills offers a variety of grades of brown fused alumina that can be sourced in both grit and powder form. The brown alumina grains and powders are available in standard grit sizes and can be shaped to your specifications.
LKAB Minerals supplies both brown fused alumina and white fused alumina for use in refractory and abrasive application. Both are high alumina, low iron, and have strong thermal properties. The brown fused alumina is a highly abrasive and is ideal for the removal of heavy rust, scale, and old coatings.
This type of abrasive can be used in compressed air blasting or wet sandblasting applications. It is a hard, pure abrasive that leaves an anchor profile before coating and is suitable for removing rust, scale, and other contaminants from non-ferrous metals, aluminum, stainless steel, glass, and stone.
Alumina has a number of unique morphologies that can influence its abrasion and friction properties. Its different amorphous phase transformations and its varied crystalline forms can be interpreted as the main characteristics to consider in abrasive application.
The amorphous phases, including a-, b-, c-, and d-aluminas, are all stable at all temperatures; however, there are many crystalline aluminas that are not stable or may have metastable forms. The amorphous phases are less suited for wear-resistant coatings due to their higher hardness and higher surface energies, but they can be useful in catalytic applications.
When alumina is calcined, it undergoes a phase transformation that can lead to a variety of crystalline aluminas with a range of different morphologies. The amorphous phase can be in the shape of a bubble, a hexagonal close-packed crystal, or an acicular crystal.
These amorphous phases can also be induced in an acidic solution, and they are often used as abrasives for machining metals and other substrates with varying degrees of hardness.
In addition to the amorphous phases, aluminum hydroxide is also able to transform into various crystal forms. The most common crystalline forms of aluminum oxide are alpha alumina, beta alumina, and gamma alumina.
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