ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Lanthania (La2O3) and zirconia (ZrO2) powders in ethanol based suspension weremechanochemically treated in a planetary ball mill for 12 hours at 200 rpm, dried and sintered atvarious temperatures from 400[removed info] to 1500[removed info]. Particles in nanometer sizes are produced after milling.X-ray diffractometry results show the formation of single phase lanthanum zirconate on subsequentheat treatment for 1h at 1500[removed info]. Phase evolution based on the intensities of the XRD plots and BETsurface area analysis indicates three stages of crystallization: below 800[removed info], between 800[removed info] and~1100[removed info], and above 1100[removed info] where reflections of La2Zr2O7 with pyrochlore structure are increasedwith further heating. Only endothermic energy peaks are observed in the differential thermal analysis(DTA) curve of the milled powders, which could be attributed to the reactions involvingdehydroxylation, decarboxylation and complete disintegration of ethanol. This indicates that probably,lanthanum zirconate has grown on sintering at high temperatures from the very fine particlesproduced by mechanochemical activation during milling. Thermogravimetric analysis has recorded atotal weight loss of ~9% from the original weight of the milled powder on sintering at 1500[removed info]. Thevalues of the surface area of the powders are found to decrease while the crystallite size of La2Zr2O7are increased with increasing temperature
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.317-318.31.pdf
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