• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.137-146
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• 1994

This experiments were focused on a modification of mechamical properties and structure in porous aluminum titanate ceramics by new additives which have been not researched yet. These were consisted of four kinds of additives i.e. Bi2O3, FeO, ZnO and NiO by addition amount of 1 wt% and 5 wt% respectively. The addition of Bi2O3 retarded a degree of syntehsis of aluminum titanate and accelerated in FeO, ZnO, NiO additives. Also, the most effective accelerator in synthesis of alunium titanate was FeO. A additives for the most effective of modification of microstructure, sharp distribtion of pore size and mechanical proterties was on ZnO addition and showed the lowest average pore size and narrowed pore size distribution. In order to improve of microstructure and pore size distribution in porous aluminum titanate ceramics was desired the addition amount of 1 wt% compare to 5 wt%.

• Proceedings of the Korean Ceranic Society Conference
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• 2004.10a
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• pp.83.1-83.1
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• 2004

• Journal of the Korean Ceramic Society
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• v.33 no.10
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• pp.1138-1146
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• 1996

Al2TiO5 powder was prepared by the sol-gel processing from th metal alkoxides ; aluminium sec-butoxide (Al(OC4H9)3 and tetraethyl orthotitanate (Ti(OC2H5)4) The particles of Al2TiO5 produced from alkoxides were measured to be below $1.5mutextrm{m}$ and mre than 90% weere below 1 ${\mu}{\textrm}{m}$ however those from commercial alumina and titania were over 0.5-7${\mu}{\textrm}{m}$ and only 60% were below 1${\mu}{\textrm}{m}$ and 90% were below 2.5${\mu}{\textrm}{m}$ Therefore Al2TiO5 powder produced from alkoxides had the narrower distributionin size than that produced from the commercial alumina and titania powders. The addition of mullite or Al2O3 powder to the prepared aluminum titanate inhibited the grain growth and this resulted in decreased and increase in density.

• Proceedings of the Korean Ceranic Society Conference
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• 2004.10a
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• pp.89.3-89.3
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• 2004

• Journal of the Korean Ceramic Society
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• v.33 no.10
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• pp.1147-1155
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• 1996

• The Korean Journal of Ceramics
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• v.1 no.3
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• pp.137-142
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• 1995

Monodispersed $Al_2O_3-TiO_2$ Powder was prepared by metal-alkoxide hydrolsis. A homogeneous nucleation/growth occurred in the solutions containing ethanol, butanol and acetonitrile, and resulted in spherical, submicrometer-sized powder. The titania and the alumina crystals were formed at $800^{\circ}C$ and $1000^{\circ}C$, respectively. These crystala were subsequently reacted each other beyond $1320^{\circ}C$ and formed $Al_2TiO_5$. The relative densities of sintered bodies prepared with as-received powder were examined at the temperature range of 1300-$1500^{\circ}C$ and they were about 79% at $1300^{\circ}C$. The formation of aluminum titanata decreased the relative density at the temperature range of 1300-$1450^{\circ}C$, and at above $1450^{\circ}C$, the relative density started to increase again. It was observed that $\alpha-Al_2O_3$-doped aluminum titanate was more stable than pure aluminum titante at $1200^{\circ}C$.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.680-683
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• 2011

This study deals with damage detection in beam structure by using modal strain energy-based technique with three different sensor types: accelerometer, lead zirconate titanate (PZT) piezoelectric sensor and electrical strain gage. First, the use of direct piezoelectric effect of PZT sensor for dynamic strain response are presented. Next, a modal strain energy-based damage detection method is outlined. For validation, forced vibration tests are carried out on lab-scale aluminum cantilever beam. The dynamic responses are measured for several damage scenarios. Based on damage localization results, the performance of three different sensor types is evaluated.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.163-164
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• 2006

A QM-ISP-4 Planetary Mill was employed to activate mechanically the mixtures of anatase and corundum at room temperature for different times. The milled powder mixtures were then sintered at $1300^{\circ}C$ for 1 h. The XRD results showed that the milled powder mixtures were completely transformed into $Al_2TiO_5$ after sintering, except the mixtures milled for 5 and 10 hours. The SEM observations showed the typical morphology of rod-like $Al_2TiO_5$ vary in the range: widths from 0.6 to $1.2\;{\mu}m$, and lengths from 3.0 to $6.0\;{\mu}m$. The rod-like $Al_2TiO_5$ formation was attributed to the positive effects caused by the mechanical activation.

• Journal of the Korean Ceramic Society
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• v.23 no.5
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• pp.9-16
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• 1986

The effect of $TiO_2$ addition to the 90wt% Cordierite-10wt% Enstatite base glass was investi-gated to understand the crystallization behavior of the glass. Glasses with addition of $TiO_2$ less than 7, 5wt% had a tendency of surface crystallization and were cracked when heat treated and in this case the crystalline phase formed was indialite. glasses with addition of $TiO_2$ more than 10wt% to 15wt% were crystallized in bulk when heat treated and were suitable for glass-ceramics. The highest microhardness 1640kg/$mm^2$ was obtained when the glass of 12.5wt% $TiO_2$ addition was heat treated at 762$^{\circ}C$ for 60 minutes for nucleation and at 1135$^{\circ}C$ for 20 minutes for crystal growth and in general higher microhardness was obtained when crystalline phase of magnesium aluminum titanate and $\mu$-cordierite were developed. Avrami equation for crystal growth kinetics was applicable in glasses of less than 7.5 wt% $TiO_2$ addition and in case of glasses of more than 10wt% $TiO_2$ addition it was not applicable because of too fast crystal growth.

• Smart Structures and Systems
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• v.7 no.1
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• pp.15-25
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• 2011

The mechanical properties obtained from mechanical tests, such as tensile, buckling, impact and fatigue tests, are largely applied to several materials and are used today for preliminary studies for the investigation of a desired element in a structure and prediction of its behavior in use. This contribution focus on two widely used different tests: tensile and fatigue tests. Small PZT (Lead Titanate Zirconate) patches are bonded on the surface of test samples for impedance-based health monitoring purposes. Together with these two tests, the electromechanical impedance technique was performed by using aluminum test samples similar to those used in the aeronautical industry. The results obtained both from tensile and fatigue tests were compared with the impedance signatures. Finally, statistical meta-models were built to investigate the possibility of determining the state of the structure from the impedance signatures.