Compaction and Pressureless Sintering of Zirconia Nanoparticles

Compaction and Pressureless Sintering of Zirconia Nanoparticles

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).

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).