Zhutňování a beztlaké slinování nanočástic oxidu zirkoničitého

Compaction and Pressureless Sintering of Zirconia Nanoparticles

článek v časopise - ostatní, Jost

en

Four nanometer-sized zirconia powders stabilized by 3 mol% Y2O3 were used for the preparation of dense bulk ceramics. Ceramic green bodies were prepared by cold isostatic pressing at pressures of 300-1000 MPa. The size of pores in ceramic green bodies and their evolution during sintering were correlated with the characteristics of individual nanopowders and with the sintering behavior of powder compacts. Only homogeneous green bodies with pores of less than 10 nm could be sintered into dense bodies (>99% t.d.) at sufficiently low temperature to keep the grain sizes in a range <100 nm. Powder with uniform particles of 10 nm in size yielded green bodies of required microstructure. These nanoparticle compacts were sintered without pressure to give bodies (diameter 20 mm, thickness 4 mm) with a relative density higher than 99% and a grain size of about 85 nm (as determined by linear intercept method).

Čtyři nanometrové ZrO2 prášky stabilizované 3 mol% Y2O3 byly použity pro přípravu hutné objemové keramiky. Keramické polotovary byly připraveny isostatickým lisováním při tlacích 300-1000 MPa. Velikost pórů v keramických polotovarech a jejich vývoj během slinování byly korelovány s charakteristikami jednotlivých nanoprášků a slinovacím chováním práškových polotovarů. Pouze homogenní polotovary s póry menšími než 10 nm bylo možné slinout do hutného tělesa (>99 % t.h.) s nanokrystalickou strukturou a rozměry 20 mm v průměru a tloušťkou 4 mm. Prášek s částicemi o velikosti 10 nm lisovaný při 1000 MPa vytvořil polotovar s póry menšími než 5 nm. Tento polotovar slinul při teplotě 1100 degC do relativní hustoty 99,7 % s průměrnou velikostí zrn 85 nm.

Four nanometer-sized zirconia powders stabilized by 3 mol% Y2O3 were used for the preparation of dense bulk ceramics. Ceramic green bodies were prepared by cold isostatic pressing at pressures of 300-1000 MPa. The size of pores in ceramic green bodies and their evolution during sintering were correlated with the characteristics of individual nanopowders and with the sintering behavior of powder compacts. Only homogeneous green bodies with pores of less than 10 nm could be sintered into dense bodies (>99% t.d.) at sufficiently low temperature to keep the grain sizes in a range <100 nm. Powder with uniform particles of 10 nm in size yielded green bodies of required microstructure. These nanoparticle compacts were sintered without pressure to give bodies (diameter 20 mm, thickness 4 mm) with a relative density higher than 99% and a grain size of about 85 nm (as determined by linear intercept method).

oxid zirkoničitý, nanočástice, částicový polotovar, póry, pórovitost, slinování

zirconia, nanoparticlulates, green bodies,pores, porosity, sintering,

2007

01.01.2007

Blackwell Publishing

USA

0002-7820

Journal of the American Ceramic Society

90

9

2735–2740

6