ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The distribution of TiO2 and Al2O3 in mullite and the glassy phase of samples obtained by sintering kaolin and Al2O3 with O to 3 wt% TiO2 has been studied. Quantitative phase analysis was performed by means of X-ray diffraction and by successive dissolution of the glassy phase and mullite in HF. The microstructure and microanalyses of the samples were determined using scanning electron microscopy and by analytical electron microscopy. With samples containing 〉1 wt% TiO2, not only two morphologically and compositionally different mullites have been determined (the large prismatic mullites and the small needle-shaped ones, embedded into the glassy matrix) but also rutile in the form of needle-shaped crystals embedded in the glassy matrix. In addition on the surface of prismatic mullites, an exsolution of the phase enriched in titanium and iron has been detected. However, the formation of tialite, Al2TiO5, has not been proved either by X-ray diffraction or by analytical electron microscopy. Using energy dispersive X-ray analysis a greater Al/Si ratio has been determined for needle-shaped mullites than for prismatic ones. Prismatic mullites have constant Al2O3 values, not dependent on the sintering temperature and on TiO2 added. The solubility of TiO2 in prismatic mullites is due to the decrease in SiO2.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01045391
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