ISSN:
1662-9752
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:
The aim of the present work is to study the influence of the partial substitution of Si byGe on the formation of the apatite-type La9.33Si2Ge4O26 phase by mechanical alloying andsubsequent annealing. Powders of La2O3, GeO2 and SiO2 were dry milled in a planetary ball millingat increasing rotation speeds of 150, 250 and 350 rpm and milling times up to 50 h. The resultingmixtures were subsequently annealed at increasing temperatures up to 1100 ºC. Single phaseapatite-like La9.33Si2Ge4O26 was obtained during mechanical alloying at high rotation speed. Thehigher the rotation speed the lower was the time required for the lanthanum germanosilicate phaseformation. For the samples in which complete reaction between initial phases did not occur duringmilling, La9.33Si2Ge4O26 was always obtained during the annealing process. The more severe wasthe mechanical alloying process the lower was the annealing temperature required for the apatitephase formation. The formation of apatite phase during mechanical alloying did not provokesignificant changes in densification behavior of the milled samples. The addition of GeO2 as rawmaterial promotes a faster formation of the apatite phase as compared to the results obtained usingonly La2O3 and SiO2
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.587-588.128.pdf
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