Compaction and Pressureless Sintering of Zirconia Nanoparticles

Abstract

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 the 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 <10 nm could be sintered into dense bodies (>99% t.d.) at a sufficiently low temperature to keep the grain sizes in the range <100 nm. Powders with uniform particles 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 the linear intercept method).

Low-temperature sintering of yttria-stabilized zirconia produced from amorphous powders

“…Zirconia-based ceramics possess excellent physicochemical properties and are widely used for the manufacture of structural, tool, and functional materials [1][2][3][4][5][6][7][8][9]. To improve the properties of ceramics and reduce the consumption of energy for their production, experts from many countries show great interest in nanosized powders due to their ability to sinter at low temperatures [1].…”

Change in pore structure of yttria-stabilized zirconia during sintering

“…Grinding of powders and pressing of powder billets greatly influence the formation of porous structure [2]. It is of importance to consider grain sizes, grain boundaries [3], and parameters of the pore space as an aggregate of closed and opened pores whose sizes have a substantial effect on the sintering of ceramic materials and, eventually, on their properties [1][2][3][4][5]. In turn, as there are agglomerates in powders, open pores can be regarded as the sum of pore channels between structural powder components: agglomerates, aggregates, etc.…”

“…The sintering of samples made of nanosized zirconia powders is studied in [1][2][3][4]. Although the sintered samples had pore channels in, at least, two size ranges, the behavior of pore space-open pore channels and closed pores-still has to be examined.…”

“…The morphology of weakly agglomerated fine powders with isometric particles of required phase composition considerably influences the forming parameters [1]. Grinding of powders and pressing of powder billets greatly influence the formation of porous structure [2]. It is of importance to consider grain sizes, grain boundaries [3], and parameters of the pore space as an aggregate of closed and opened pores whose sizes have a substantial effect on the sintering of ceramic materials and, eventually, on their properties [1][2][3][4][5].…”

Effect of starting powders on the sintering of nanostructured ZrO2ceramics by colloidal processing

“…Recently, Trunec and Maca [22] also reported the low-temperature sintering of tetragonal nanosized zirconia (1100…”