What Is the Molecular Weight of Alumina?

Alumina (Al2O3) is a white or nearly colorless crystalline substance used as a raw material in aluminum metallurgy, industrial ceramics and chemical processing industries. Free alumina also occurs naturally as the mineral corundum or gemstone rubies and sapphires.

The Bayer Process is the primary method for producing industrial-scale alumina production. Depending on the fuel used during calcination, its effects on environmental indicators like marine eutrophication or terrestrial acidification vary.

1. Density

Density, defined as mass divided by volume, is an essential property that influences other physical characteristics like ceramic shrinkage during calcination and porosity. Density can typically be reported using SI units of kilograms per cubic metre or cgs units of grams per cubic centimetre but other units may also be employed for reporting purposes.

Aluminia (also referred to as Alumina) can be identified by its chemical formula Al2O3. Alumina appears as a white crystalline powder and can be found naturally in rocks of both igneous and metamorphic origin, where it forms as corundum mineral deposits. Alumina finds use as an abrasive, refractory material and raw material for advanced ceramic production, among many other applications. Chronic inhalation of Alumina dusts may cause lung damage while it remains soluble in acids but remains insoluble in water. Acidity increases with acidity but water does not affect it significantly

2. Melting Point

Melting point is the temperature at which solid materials transition to liquid states. This transition occurs due to forces holding together atoms that compose a substance; when temperatures increase, these forces begin to weaken, and particles can move more freely, ultimately leading to melting.

Aluminum’s ability to withstand high temperatures makes it ideal for electrical, chemical and aerospace applications, while also being utilized in abrasion-resistant textile guides, pump plungers and chute liners.

Molecular Dynamics (MD) simulations and thermodynamic analysis were employed to investigate the effect of size on melting points for different geometries of alumina nanocrystals. Results do not suggest any significant decrease in melting point for oxide layer covering spherical aluminum particles compared with previous works which reported significant depressions of planar aluminum oxide films’ melting points.

3. Electrical Conductivity

Aluminium oxide (Al2O3) is one of the world’s premier engineering ceramics. It is lightweight, ductile and corrosion-resistant; additionally it boasts excellent mechanical properties like strength and toughness for use in cutting tools and wheels that abrasion-resistant applications.

Each aluminum atom contains 13 electrons that are not held tightly by its nucleus and thus free to move freely within it, contributing to its electrical conductivity.

Electrical conductivity can be measured by passing a known current through a material and measuring its voltage drop; the higher its conductivity is, the better it conducts electricity. In this study, researchers investigated the influence of relatively low additions of MWCNT to spark plasma sintered Al2O3/SiC and Al2O3/ZrO2/MWCNT composites’ electrical conductivity; their results show that MWCNT addition can significantly enhance it.

4. Thermal Conductivity

Thermal conductivity refers to the ability of materials to transmit heat via convection currents. Its purpose is crucial for evaluating and optimizing thermal management systems, improving energy efficiency, assuring safety, guiding materials selection processes and ultimately increasing performance and sustainability in products and processes.

Aluminum oxide (Al2O3) is a white crystalline powder created as an by-product of electrolytic production of aluminium metal. Used primarily as an abrasive for grinding and cutting metals, Al2O3 is also often an essential ingredient in refractories and ceramic products.

Hot-pressed alumina-graphene composites exhibit strong microstructural anisotropy. Graphene flakes distributed perpendicular to pressing direction are present throughout, and their thermal conductivity (measured along pressing direction) is much lower than pure alumina (measured along this same direction). This confirms graphene’s negative impact on thermal conductivity of alumina.

5. Thermal Stability

Stability of Alumina as an Energy Composite Material

Increased Alumina Suspension Viscosity due to PVA with Rising pHIt can be explained by flocculation of solid particles caused by their longer and more stretched conformation, due to more dissociated Acetate Groups on Alumina Surface ChargeI.

On TG/DSC curves below 400 degC, weight losses due to aluminum powder reactions with inert gas show an adiabatic reaction before suddenly increasing around 400-550 degC due to an AlF3 transformation process.

6. Corrosion Resistance

Corrosion resistance is an integral characteristic of any metal or ceramic used for industrial applications, as corrosion-weakened parts can quickly break down in harsh working environments, potentially becoming damaged beyond repair. Alumina’s corrosion resistance depends greatly upon its phase composition.

Aluminum’s corrosion-resistance makes it so popular across numerous industries, which explains its oxidation phenomenon and subsequent widespread adoption.

Sintering alumina material with lower amounts of mullite 3Al2O32SiO2 can improve its corrosion resistance, but this may result in decreased acid resistance. According to X-ray diffraction analysis, the effect of adding different concentrations of La2O3 on acid solubility depends on corrosion time; an optimal amount was identified as 3 wt% La2O3.

7. Thermal Stability

Thermal stability of alumina is fundamental to its refractoriness and chemical inertness in both reducing and oxidizing environments, making its use in textile guides, pump plungers, chute linings and discharge orifices possible. Furthermore, hardness, wear-abrasion resistance and close dimensional tolerance capability make alumina ideal for industrial uses like textile guides, pump plungers, chute linings and discharge orifices.

Contrary to other oxide ceramics, alumina exhibits multiple metastable phases beyond its thermodynamically stable alpha phase. These include the gamma, delta, theta, and eta phases which possess distinct oxygen sub-lattices in its face-centered cubic (fcc) crystal structure compared to alpha.

Radiolabeled 26Al inhalation studies demonstrated that alumina acted as an insoluble dust, with approximately 45 percent being cleared out within one day and the rest remaining for longer. This suggests it acts as an insoluble dust since its molecules cannot easily dissolve into water.

8. Hardness

Hardness of Alumina is an extremely significant property that determines its resistance to physical impact damage. Alumina boasts an extremely hard material with a Mohs scale hardness of 9 and can only be scratched by similarly hard materials such as diamond.

Hardness in metals depends on their crystalline structure and chemical composition; specifically, how atoms arrange themselves within an alloy lattice at an atomic level.

The hardness of alumina can be increased using various production methods such as hot pressing, liquid phase sintering, high pressure sintering, spark plasma sintering, two-step sintering and two-step sintering. Furthermore, various treatments like acid washing surface treatment grinding and acid washing may be employed to enhance its hardness; however, its hardness will still be determined by factors like agglomeration and voids within its surface layers.

9. Thermal Stability

Alumina has several appealing properties, such as high hardness, resistance to abrasion and chemical inertness that make it an intriguing material for use across various applications. However, temperature and humidity changes may alter its performance significantly.

Thermal stability of alumina is determined by its ability to resist oxidation and decomposition, particle size and surface chemistry; doping with tin may help stabilize it further for reduced reactivity and improved thermal stability.

Alumina offers several key advantages when used for insulation applications. It can withstand thermal shocks while maintaining structural integrity even under harsh environmental conditions, making alumina one of the premier materials available. Furthermore, its mechanical properties such as strength and stiffness can be assessed using an Alemnis in-situ nanoindentation tool within a Zeiss LEO 1450 SEM to conduct load-displacement tests on individual powder particles made of alumina powder.

10. Density

Density of material refers to its mass divided by volume. This property helps determine its strength, resilience and resistance against various types of strain and stress as well as predict corrosion resistance and thermal stability.

Alumina is highly resistant to chemicals, non-reactive element that extends equipment and component lifespan. Abrasion resistant with close dimensional tolerance capabilities make alumina a popular choice for textile guides, pump plungers and chute lining applications.

Densities for advanced ceramics range from 2.5 grams/cm3 for sintered silicon carbide to around 6 g/cm3 for magnesia-stabilised zirconia, with Alumina typically being an essential part of these ceramics; its density increases depending on its purity level as more voids it contains equals greater density.