Aluminum titanate

The aluminum titanate (tialite, Al2TiOs) has specific properties such as high melting point, low thermal expansion coefficient ((-l-3)-(-19) K ), and high thermal shock resistance that make it interesting for applications such as exhaust port lines in automobiles, turbocharge liners, and missile cone nose. 

Zaharescu and coworkers [6] studied the preparation of the monocomponent Ti02, AI2O3, MgO, Si02, nanometric powders, binary Ti02-Al203 reactive powders obtained by co-gelation, and multicomponent reactive powders prepared by cogelation of binary powders with different dopants. 

Based on the DTA/TGA results, Si02 and Ti02 samples were pre-annealed at 300 °C, whereas all the other (mono- and multicomponent) samples were thermally treated at 450 °C. 

The sintering tendency has been established by measuring the relative density and the linear shrinkage of the samples thermally treated at temperatures between 1250 and 1450 °C. The linear shrinkage is much higher in the case of the samples obtained starting with reactive powders. However, the final density is relatively low. The decrease in density with increase in temperatures is explained by tiahte formation that has a lower density than the initial oxides [116]. 

To obtain dense ceramics, the amorphous binary Al20s-Ti02 powders were simultaneously consolidated and reacted to form Al2TiOs by the field-activated sintering technique (FAST) [117]. 

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See also Corundum transition to, 2 403 P-Alumina, 2 408 y-Alumina, 2 391, 403, 404, 406t y-Alumina, 2 403, 404, 406t 8-Alumina, 2 404, 406t 0-Alumina, 2 404, 406t K-Alumina, 2 404, 406t p-Alumina, 2 394-395 Alumina-aluminum titanate, 5 570 Alumina-chromia-thoria, catalytic aerogels, l 763t... 

Aluminum sulfide, 2 284 Aluminum titanate, 5 570, 578 25 46 Aluminum triacetylide, 1 179 Aluminum trifluoride, 2 360, 361-362, 377 health and safety factors, 2 363 high purity, 2 363... 

Padture, N.P., Bennison, S.J. and Chan, H.M. Flaw-tolerance and crack-resistance properties of alumina-aluminum titanate composites with tailored microstructures ,... 

Taruta, S., Itou, Y., Takusagawa, N., Okada K. and Otsuka, N. Influence of aluminum titanate formation on sintering of bimodal size-distributed alumina powder mixtures , J. Am. Ceram. Soc. 80 (1987) 551-556. 

Uribe, R., Baudin, C. (2003), Influence of a dispersion of aluminum titanate particles of controlled size on the thermal shock resistance of alumina , 7. Am. Ceram. Soc., 86(5), 846-850. 

We have published a demonstration of this strategy for an isopropanol-based aluminum-titanate sol-gel system.The seleeted addition of ethyl acetate was effective at preventing striation formation for the aluminum-titanium recipe. More... 

Taylor, D.J., and Bimie, D.P., 111, Striation prevention by targeted formulation adjustment aluminum titanate sol-gel coatings, Chem. Mater., 14, 1488, 2002. 

Materials such as aluminum titanate and silicon carbide appear to be promising for high-temperature catalytic combustion. However, problems such as extrudability, the application of washcoats, and reaction with deposited washcoats are not solved yet. For instance, when hexa-aluminate, presented in the introduction to this section, was applied to silicon carbide monoliths, solid-state reactions occurred at 1200-1400 C [76], causing exfoliation of the coating and the formation of new phases. The application of an intermediate mullite layer was suggested as an approach to hinder these solid-state reactions. 

Mullite-aluminum titanate 3AI2O3 Si02-Al203 Ti02... 

Using acoustic emission and thermal contraction data, Ohya et al. measured the functional dependence of the microcracking temperature of aluminum titanate ceramics on grain size as the samples were cooled from 1500°C. The following results were obtained ... 

Aluminum titanate AIJiO, 12004-39-6 181.827 refrac solid I860 ... 

Mullite aluminum titanate - 1650 Good thermal shock resistance 166... 

Porous aluminum titanate DMO has both a low thermal expansion coefficient (nearly zero at least up to 600°C) and a low thermal conductivity, suggesting possible applications in thermal barriers and abradable seals for turbine rotor shrouds [116] and automobile exhaust port liners and gas desulfurization nozzles [117]. Other possible thermal applications of silicon carbide reinforced DMO include heat exchangers [117] and flaps and seals in the afterburners of jet engines [119]. In addition, SiC particulate-reinforced DMO could serve as a lossy insert for high powered microwave tubes, withstanding temperatures up to 1000°C in ultrahigh vacuum. 

Boccaccini [113,114] has reviewed the dispersion reinforcement of glass matrix composite materials. The thermal shock resistance of glass can be improved by the addition of aluminum titanate (Al2Ti05) particles [115,116]. 

A SEM micrograph of crack propagation, obtained in situ in an Al203-Al2Ti05 composite, is shown in Fig. 8.64. The advancing crack tip appears to be attracted to the alumina-aluminum titanate [henceforth A-AT] interphase interfaces. This observation implies that the high residual stress (and possibly the elastic modulus... 

Figure 1.14 The microstructure of a commercial cordierite glass ceramic (Coming Code 9606). The predominant phase with somewhat rounded grains is cordierite and the angular, needle-shaped crystals are magnesium aluminum titanate. (From Ref. 85.)...

Engines Valve seats Heat resistance Aluminum titanate... 

Figure 17.27 Cross-sectional view ofthe combustion section of an internai combustion engine. The shaded parts are manufactured from silicon nitride (piston head, valve seats, turbocharger rotor), alumina (cylinder liner), or aluminum titanate (exhaust pipe lining).

Different refractory ceramics are used for the filter matrix. Most common are cordierite-, aluminum titanate-, and silicon carbide-based products [15, 17-21]. Typical physical properties for these materials are provided in Table 20.1. AU materials can withstand very high temperatures. Key differences between these... 

Aluminum titanate composition Cordierite composition Silicon carbide... 

Fig. 20.4 SEM of honeycomb wall of high porosity cordierite left) and aluminum titanate filters...

Fig. 20.20 Examples of durability test results over repeated worst-case regenerations with zeolite SCR catalyst coated high porosity aluminum titanate filter [51]...

Rose D, Pittner A, Jaskula C, Boger T, Glasson T, DaCosta V M (2007) On Road Durability and Field Experience Obtained with an Aluminum Titanate Diesel Particulate Filter. SAE Technical Paper 2007-01-1269... 

Taylor D.J., Birnie D.P. A case stndy in striation prevention by targeted formulation adjustment Aluminum titanate sol-gel coatings. Chem. Mata-. 2002 14 1488-1492 Thouless M.D. Decohesion of films with axis3nmnetric geometries. Acta Metall. 1988 36 3131-3135... 

Andrianainarivelo M., Corriu R., Leclercq D., Mutin P.H., Vioux A. Mixed oxides Si02-Zr02 and Si02-Ti02 by a non-hydrolytic sol-gel route. J. Mater. Chem. 1996 6 1665-1671 Andrianainarivelo M., Corriu R.J.P., Leclercq D., Mutin P.H., Vioux A. Non-hydrolytic sol-gel process—zirconium titanate gels. J. Mater. Chem. 1997 7 279-284 Andrianainarivelo M., Corriu R.J.P., Leclereq D., Mutin P.H., Vioux A. Non-hydrolytic sol-gel process aluminum titanate gels. Chem. Mater. 1997 9 1098-1102 Apperley D., Hay J.N., Raval H.M. Silica-dimethylsiloxane hybrids-non-hydrolytic sol-gel synthesis and characterization by NMR spectroscopy. Chem. Mater. 2002 14 983-988... 

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