aluminium titanate offers excellent thermal shock resistance, low thermal conductivity and optimal chemical resistance against molten metals, making it suitable for many applications in Non-Ferrous cast houses and foundries such as crucibles, riser tubes and pouring spouts.
Synthesis
aluminium titanate is a polycrystalline ceramic compound created by reacting alumina with titanium dioxide in an exact proportion, creating an aluminum titanate material known for its non-wettability to molten metal, making it perfect for use in the metallurgical industry. Furthermore, this ceramic has excellent thermal shock resistance due to low thermal expansion and Young’s modulus values and can even be found used as spacer rings on diesel particulate filters as well as in foundry crucibles/launders/nozzles riser tubes/ pouring spouts/master moulds glass industries – ideal properties!
synthesised alumina-titania ceramics are composed of an ideal stoichiometric composition to provide good chemical resistance and high refractoriness, while their sintering process ensures exceptional densification. Sinters produced have an outstanding melting point of 1860degC and thermal expansion coefficient, as well as outstanding properties regarding aluminium liquidation as well as no-wettability and total gas impermeability – features that have no equal when it comes to properties like chemical resistance or total gas impermeability.
Sol-gel processing of alumina-titania composites reduces residual a-alumina and rutile phases that affect mechanical strength, leading to higher mechanical strengths than those reported in literature. Mechanical strengths for composites with more rutile were however lower due to abnormal grain growth patterns as well as decreased densification associated with excessive content of this mineral.
Preparation
aluminium titanate ceramic is an oxide material known for its exceptional chemical resistance, low thermal conductivity and excellent thermal shock resistance due to its extremely low coefficient of expansion. Aluminum titanate is typically made by reactively sintering alumina (Al2O3) and titania (TiO2) powders into a solid solution at stoichiometric proportions; other refractory oxides like magnesium, ferric iron zirconium or silicon can also be doped into it in order to further enhance its properties.
Preparing aluminium titanate involves selecting high bauxite with 75%-80% aluminum oxide content by weight, evenly mixing this bauxite with industrial pure aluminum oxide and industrial pure titanium dioxide as the main raw materials, then performing solid-phase reaction in order to obtain micropowders of alumina-titanate ceramic micro-powders.
Densification of alumina-titanate ceramics can be achieved either through pressure application or high temperature treatments, and their density increased to 1850 degC by applying either pressure or high temperature treatment. As a result, they display good thermal stability up to this temperature range, and outstanding thermal shock resistance. Unfortunately pure alumina-titanate is unstable between 750 degC and 1350 degC due to thermal shock stress; to overcome this issue mullite and celsian are used together with pure alumina-titanate which reduces melting point to 1860 degC for better thermal expansion coefficient control.
Properties
aluminium titanate is a ceramic oxide from the pseudobrookite structure group with high melting points, low thermal conductivity and excellent thermal shock resistance properties that make it suitable for use in severe thermal environments such as foundry technology, metallurgical melting and refractory applications.
Alumina-Titanium composites can be prepared through colloidal filtration and rapid reaction sintering of alumina/titania green bodies. The resultant material has near theoretical density with bimodal grain size distribution and higher mechanical properties than reported for alumina – Vickers hardness, flexural strength and fracture toughness being particularly noteworthy among them.
By employing FE-SEM and EDS analysis, the microstructure of sintered AT-alumina composites was investigated. Results demonstrated that AT grains were intimately mixed with the alumina in the composite without adding rutile (0 R). As more rutile ( 30-40wt%) is added into the blend, its addition results in thickening of the interface between AT grains and the alumina/AT interface due to AT grain formation.
Aluminium titanate’s excellent thermal shock resistance makes it the ideal material for conveying and dosing components for non-ferrous metal melts, with temperature differences up to several hundred degrees being tolerated without issue. This allows stable processing of non-ferrous melts while simultaneously increasing casting plant availability and maintaining maximum casting plant uptime. Furthermore, AT components boast outstanding chemical, wear resistance as well as corrosion resistance properties.
Applications
aluminium titanate ceramic offers excellent thermal shock resistance, as it can withstand sudden temperature changes with minimal impact, thanks to its very low coefficient of thermal expansion and microstructure porosity. Due to this characteristic, this material makes an excellent material choice for use in foundry technology and metallurgical melting applications.
aluminium titanate exhibits exceptional properties that make it ideal for applications involving molten aluminum, including resistance to wetting by liquid alloys of molten aluminum, total gas impermeability, and a very low thermal expansion coefficient. Therefore, aluminium titanate can withstand harsh environmental conditions like high-temperature, alkali environments, corrosion conditions as well as harsh temperature variations – something metallic or polymer materials cannot do. Machinable ceramic material is widely utilized in die casting machines for applications like sprue bushing, riser tube/stalks and auto pour ceramic ladles; also, as refractories for aluminium industry applications and as elements in diesel filter media filters.