Alpha alumina is one of the most important ceramic materials with propertie s and applications having been thoroughly explored. Fused Cast Alpha Alumin a block comprises about 99% alumina (90% alpha alumina and 4% beta Al2O3),
0.4% SiO2 and 0.9% Na2O.Alumina (Al2O3) is an aluminium compound with many crystalline forms or pol ymorphs. Alumina exists in many forms, ?, ?, ?, ?, ? ?, ?, ?, ?. Alpha alumina or corundum is the only thermody namically stable form amongst the different polymorphs. Alpha alumina stabl e at very high temperature and this property is also used as refractory and thermal barrier.
Alumina is characterized with high compression strength, high hardness, goo d resistance to abrasion, high resistance to chemical attack, high thermal conductivity, good resistance to thermal shock, and high degree of refracto riness.
Its applications are widespread, and include spark plugs, tap washers, pump seals, electronic substrates, grinding media, abrasion resistant tiles, cu tting tools, bioceramics, (hip-joints), body armour, laboratory ware and we ar parts for the textile and paper industries. It is also used in the manuf acture of monolithic and brick refractories. It is also used mixed with oth er materials such as flake graphite for even more severe applications.
Fused Cast Alpha Alumina block is relatively resistant to molten glass corr osive action, though not at the level of Baddeleyite. Most importantly, it does not develop a passivation layer like fused cast AZS refractory. It dis solves slowly in the glass through a concentration gradient at the contact surface. Temperature and glass velocity tangential to the surface determine the corrosion speed.
Fused cast alpha alumina block is an ideal product for the lower temperatur e zones of the glass melting furnaces due to its high density, superior cor rosion resistance and low blister potential. It is also an ideal material f or Metallurgical Titanium Furnace because the superior thermal stability.
Sunrise refractory offers high quality fused cast alpha alumina blocks at a competitive price for glass furnaces.