PHYSICOMECHANICAL PROPERTIES OF CERAMIC MATERIALS
PREPARED WITH CHEMICAL DISPERSION OF ALUMINUM ALLOY
A. D. Shlyapin,
A. Yu. Omarov,
V. P. Tarasovskii,
Yu. G. Trifonov,
and A. I. Airikh
Translated from Novye Ogneupory, No. 7, pp. 30 – 33, July, 2013.
Original article submitted February 4, 2013.
An aluminum hydroxide residue forms during chemical dispersion of aluminum alloy grade AK12, containing
a considerable amount of Na ions. These ions affect the structure and phase composition of ceramic speci
mens, since as a result of sintering they form a second phase, i.e., nepheline, which is uniformly distributed
grain boundaries. The effect of degree of washing of original Al
powder on physicomechanical
properties of ceramics from these powders, such as ultimate strength in bending, impact strength, density, po
rosity, and crack resistance, is studied.
Keywords: chemical dispersion, aluminum alloy grade AK12, aluminum oxide powder, ceramic material.
A basic trend of contemporary development of world in-
dustrial production is a change-over to energy-saving tech-
nology, which provides a high level of production waste uti-
lization, and as a consequence good ecological cleanliness
for this production. Preparation of high quality aluminum ox-
ide powder by means of aluminum alloy chemical dispersion
is an important task, since in a manufacturing process a con
siderable amount of waste remains from treating aluminum
alloys, whose utilization by traditional methods is connected
with considerable energy consumption. Previously  a
mechanism has been proposed for processing aluminum al
loy machining waste into aluminum oxide powder with a
broad spectrum of properties, which may find application in
ceramic and refractory production. Results are given below
for a study of the effect of degree of aluminum hydroxide
cleaning from NaOH on corundum ceramic physicomechani
cal properties, prepared from these powders. The degree of
powder cleaning of aluminum hydroxide from NaOH was
evaluated from washing water pH.
TEST CERAMIC SPECIMEN PREPARATION
Specimen manufacture for studying residues, i.e., prod
ucts of chemical dispersion of aluminum alloys, may be pre
sented in the form of a scheme provided in Table 1. The
scheme uses traditional and generally accepted ceramic and
powder metallurgy technology, and equipment. An exception
is only the first production operation, for which it is neces-
sary to develop a construction and prepare a reactor  of al-
kali-resistant materials for chemical dispersion of aluminum
alloys. The residue obtained (in the form of a suspension) is a
reaction product in an alkaline medium, and therefore it is
necessary to wash alkali from it with distilled water by
decantation (production operation No. 2). The residue
formed is transferred into a vessel of alkali-resistant plastic
(see Fig. 1). Then distilled water is poured into the vessel in
an amount of 12 – 15 liters of water for 300 – 500 g of dry
residue; then it is stirred and stood for 40 – 60 min. The layer
of liquid formed above the residue after washing is precisely
poured off, and the residue remains in the vessel.
Decantation is performed repeatedly to a prescribed medium
pH value (washing liquid). As a result of successive
decantation there is a reduction in Na
ion concentration as a
result of removal from the suspension.
After completion of residue washing it is separated from
liquid by vacuum filtration (production operation No. 3).
Washed residue dried in air (production operation No. 4) pro
vides powder that is calcined in air (production operation
No. 5) with the aim of synthesizing oxide phase. A tempo
rary organic binder is added to the powder for charge prepa
ration (production operation No. 6), and polyvinyl alcohol
(PVA) is selected. A 10% aqueous solution of PVA is used.
Specimens are molded (production operation No. 7) in a hy
draulic press by two-sided compaction in a steel die, com
Refractories and Industrial Ceramics Vol. 54, No. 4, November, 2013
1083-4877/13/05404-0288 © 2013 Springer Science+Business Media New York
FGBOU VPO Moscow State Industrial University, Moscow,
ZAO NTTs Bakor, Shcherbinka, Moscow Region, Russia.