Vacuum sintering of plasmochemical powders based on ZrO{sub 2}. II. Effect of sintering time at high temperature on the phase composition and mechanical properties of ceramics

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Powder Metallurgy and Metal Ceramics

DOI:https://doi.org/10.1007/BF00559848· OSTI ID:237621

Savchenko, N L; Sablina, T Yu; Kul`kov, S N ^[1]

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1. Institute of Physics and Material Science, Tomsk (Russian Federation)

High-density tetragonal zirconia, partially stabilized with Y{sub 2}O{sub 3}, produced by low-temperature T < 1600{degrees}C sintering is characterized by exceptionally high strength and fracture toughness ({sigma}{sub bend}{approx}2300 MPa, K{sub Ic} {approx}15 MPa {center_dot}m{sup 1/2}). However, the properties of this material depend strongy on temperature: as the temperature increases to 800 {degrees}C the strength and toughness rapidly decrease. On the other hand, it is well known that sintering at temperatures higher than 2100 {degrees}C (in the area of formation of the cubic phase) makes it possible to produce ceramics whose mean strength and fracture toughness value {sigma}{sub bend} = 400-800 MPa, K{sub Ic} {approx}7 MPa{center_dot}m{sup 1/2} remain constant to 1000{degrees}C. The cooling rate after sintering in the region of the cubic phase has a strong effect on the phase composition of the material. In rapid cooling the cubic phase of ZrO{sub 2} undergoes diffisionless transformation to the so-called T{prime}-phase, which differs from T-ZrO{sub 2} by a large amount of dissolved Y{sub 2}O{sub 3} and a low degree of tetragonality. Slow cooling leads to the formation of precipitates of the tetragonal phase in the cubic phase by the diffusion mechanism. There are almost no data on the properties of ZrO{sub 2}-3 % (mol) Y{sub 2}O{sub 3} ceramics produced by sintering in the two-phase (K + T) region at temperatures above 1600{degrees}C. The aim of this work was to study the mechanical properties and phase composition of the above oxides after high temperature vacuum sintering.

• Sponsoring Organization: USDOE
• OSTI ID: 237621
• Journal Information: Powder Metallurgy and Metal Ceramics, Journal Name: Powder Metallurgy and Metal Ceramics Journal Issue: 1-2 Vol. 34; ISSN PMMCEF; ISSN 1068-1302
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERAMICS
FRACTURES
GRAIN GROWTH
MECHANICAL PROPERTIES
PHASE STUDIES
SINTERING
VACANCIES
YTTRIUM OXIDES
ZIRCONIUM OXIDES