PROBLEMS IN MAKING A DENSE NANOCERAMIC
A. V. Belyakov
Translated from Novye Ogneupory, No. 4, pp. 109 – 115, April, 2009.
Original article submitted March 5, 2009.
The classification of nanomaterials is proposed. Problems are considered in making nanoceramics from
nanopowders of various grain sizes: nanopowder preparation, the manufacture of molding materials, molding
blanks, and sintering them. There is a brief discussion of ways of making ceramic nanocomposites in the de
composition of unstable solid phases and the use of nanodimensional particles. Template methods are dis
cussed for making ceramic nanocomposites.
Keywords: nanoceramic technology, unstable-phase decomposition, template synthesis.
Nanomaterials have many promising applications [1, 2].
They are materials in which a major working property is de-
termined by structural elements of size less than 100 nm. On
one classification, ceramic structure elements of size less
than 1 ìm relate to the substructure .
On geometrical parameters, nanomaterials are divided
into 0-dimensional (0D), namely nanoparticles, nanoclusters,
defect associations, quantum points, and other structure ele-
ments of size less than 100 nm; 1-dimensional (1D) of diam-
eter less than 100 nm: nanotubes, whisker crystals, and
nanofibers; 2-dimensional (2D) of thickness less than
100 nm: nanofilms, nanolayers, nanocoatings, and the
boundaries of crystals, phases, and blocks; and 3-dimen
sional (3D): monolithic items consisting of structure ele
ments of size less than 100 nm or containing such elements
of size less than 100 nm subject to the condition that those el
ements determine some important working property. Their
materials include fibers and films of thickness more than
100 nm if they consist of structure elements of size less than
100 nm or contain structure elements of size less than
100 nm but subject to the conditions that the nanodimen
sional structure elements determine some important working
property. If these materials with one, two, and three dimen
sions do not consist solely of single-phase structure elements
of size less than 100 nm but in fact contain structure ele
ments of size less than 100 nm determining a major working
property, the material may be considered as a nanocompo
site. As a rule, the nanodimensional structure elements
should be of a phase composition differing from that of the
surrounding solid phase (dispersion medium).
Nanotechnologies are ones that produce nanomaterials or
ones in which the combination of required properties is at-
tained by the use of nanodimensional structure elements or
nanoparticles as initial materials or intermediate products. In
the latter case, ceramic nanotechnologies involve the use of
nanoparticles that reduce the sintering temperature and sub-
stantially improve the properties of the ceramic; also, the use
of nanopowders is involved for obtaining a transparent ce-
ramic; there is also the use of finely divided powders devel-
oped by Pivinskii. In the final ceramic material, nanodimen-
sional structure elements as a rule are absent, but they pro
vide the attainment of the required properties.
Structure elements with nanodimensions are always
present in any traditional ceramic material, but in a
nanomaterial they determine the basic working properties.
For example, nanomaterials include the long-known hetero
geneous catalysts, in which the active centers have
nanodimensions; also, glasses stained by colloidal metal par
ticles; and also color centers in photochromic glasses, and
materials whose properties are determined by nanodi
mensional groups of point defects in crystals (defective crys
tals), and so on. Structure elements with nanodimensions are
basic to research in colloid chemistry. It is correct to say that
nanoparticles and nanomaterials differ substantially in prop
erties from materials containing larger particles. Then any
substance containing structure elements with nanodimen
sions should have unusual properties, and the transition to
nanostructures should open up vast scope for research on
these new materials. Rapid developments are occurring in
nanomaterial technology in relation to the search for new
materials with unusual properties and as a consequence of
Refractories and Industrial Ceramics Vol. 50, No. 2, 2009
1083-4877/09/5002-0136 © 2009 Springer Science+Business Media, Inc.
Mendeleev Russian Chemical Engineering University, Moscow,