A thermoanalysis of phase transformations and linear shrinkage kinetics of ceramics made from ultrafine plasmochemical ZrO2(Y)–Al2O3 powders; Journal of Thermal Analysis and Calorimetry; Vol. 115, iss. 2

Sonraí bibleagrafaíochta
Parent link:	Journal of Thermal Analysis and Calorimetry.— , 1969- Vol. 115, iss. 2.— 2014.— [P. 1439-1445]
Príomhchruthaitheoir:	Surzhikov A. P. Anatoly Petrovich
Údar corparáideach:	Национальный исследовательский Томский политехнический университет Институт неразрушающего контроля Кафедра физических методов и приборов контроля качества
Rannpháirtithe:	Frangulyan (Franguljyan) Т. S. Tamara Semenovna, Gyngazov (Ghyngazov) S. A. Sergey Anatolievich
Achoimre:	Title screen The methods of X-ray diffraction analysis, thermogravimetric analysis, differential scanning calorimetry, and dilatometry are used to study special features of the structural-phase state of the 80 mass% ZrO2(Y)-20 mass% Al2O3plasmochemical powders (PCPs) and their effects on the sintering of composite ceramics. It is revealed that the ZrO2(Y)-Al2O3 powder composite represents a mechanical mixture containing crystalline tetragonal zirconium dioxide and aluminum oxide nanoparticles, the latter found in an amorphous state and partially included into the ZrO2(Y) lattice, thus forming metastable solid solutions of variable composition. Heating of the composite powder within the temperature range 740-1,000 C reveals an exothermal effect associated with decomposition of metastable states of aluminum oxide. This is accompanied by the formation of the corundum-phase nuclei having subcritical dimensions. They achieve the critical sizes at higher temperatures T > 1200 C, when α-Al2O3 is finally crystallized. The shrinkage response of the powder compacts during non-isothermal sintering is measured in a sensitive dilatometer. It is shown that the shrinkage curve consists of several stages that closely correlate with the concurrent structural-phase transformation in the composite ZrO2(Y)-Al2O3 powder mixture. The decisive contribution into shrinkage during non-isothermal sintering of composite comes from the high-temperature stages with the maximum shrinkage rate at the temperatures 1,250 and 1,550 C. It is found out that the regime of sintering the ultrafine PCPs (T = 1,600 C, t = 1 h) allows producing composite ceramic materials with a porosity of Q ≈ (5-7) %, microhardness H v = 12.3 GPa, and crack resistance š 1c = (10-11) MPa m0.5. Режим доступа: по договору с организацией-держателем ресурса
Teanga:	Béarla
Foilsithe / Cruthaithe:	2014
Ábhair:	электронный ресурс труды учёных ТПУ керамика порошки фазовые переходы спекание алюминий оксид цирконий диоксид
Rochtain ar líne:	http://dx.doi.org/10.1007/s10973-013-3455-y
Formáid:	Leictreonach Caibidil leabhair
KOHA link:	https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=649244