SCIENTIFIC RESEARCH AND DEVELOPMENT
POWDER COMPACT STRUCTURE.
PART 3. THEORETICAL ANALYSIS OF SINTERING
IN POWDER COMPACTS WITH INHOMOGENEOUS POROSITY
A. V. Galakhov
Translated from Novye Ogneupory, No. 9, pp. 35 – 43, September 2014.
Original article submitted July 17, 2014.
Publications devoted to theoretical analysis of powder compact sintering are reviewed taking account of parti
cle packing inhomogeneity within it. The methods used for resolving the problem are conditionally divided
into analytical and numerical. It is shown that in order to obtain results agreeing with experimental observa
tions more extensive possibilities may be realized using numerical methods in combination with computer
modeling of particle packing. Examples are provided of implementing the method applied to oxide ceramic
Keywords: powder compact, structure, inhomogeneity, sintering, analytical methods, numerical methods.
In sections of the present review published previously in-
formation about particle packing inhomogeneity in a powder
compact, criteria for its evaluation, and reasons its genera-
tion have been collected and presented. Results have been
provided in part 1 of the clearest experimental work for the
effect of this factor on sintering . In part 2  the main at
tention was devoted to reviewing methods for improving
powder compact structural inhomogeneity, which are condi
tionally separated into production and structural. Part 3 is de
voted to a review of theoretical methods used for evaluating
the effect of powder compact structural inhomogeneity on
sintering and structure formation within sintered material.
Theoretical description of sintering occupies a consider
able place in contemporary materials science, or more pre
cisely its sub-division powder metallurgy. Today there are
two main fundamentally differing approaches to describing
sintering; classical sintering theory  and phenomeno
logical [4, 5]. The first rests on physical constants at the level
of individual particle reaction. Phenomenological theory
based on continuum solid mechanical equations (viscous me-
dium) requires for its implementation existence of empirical
coefficients used for describing macroscopic problems of
powder technology. The author of this review has attempted
to present as much as research results as possible for theoret
ical evaluation of the effect of powder compact structural
inhomogeneity on sintering using both physical and
phenomenological theory. In addition, in work on this theme
one more tendency is considered, requiring conditional clas
sification. Whereas the majority of early research for study
ing transformation of a pore space during sintering was per
formed by means of analytical (often cumbersome and com
plicated) relationships, subsequently numerical methods are
used more often for this purpose. In spite of the fact that in
some cases in order to obtain results computer technology is
used actively, separation of material into two sub-sections,
i.e., analytical and numerical methods, is correct.
A quality criterion of powder compact structural
inhomogeneity with a monomodal pore size distribution is
the width of this distribution . In analyzing sintering in
such compacts it is convenient to use a functional form of
this distribution. A similar approach has been demonstrated
Refractories and Industrial Ceramics Vol. 55, No. 5, January, 2015
1083-4877/15/05505-0448 © 2015 Springer Science+Business Media New York
Part 1 of the article published in Novye Ogneupory No. 5 of
2014, Part 2 in No. 6 of 2014.
FGBUN A. A. Baikov Institute of Metallurgy and Materials Sci
ence, Russian Academy of Sciences, Moscow, Russia.