STUDY OF REFRACTORY MATERIALS FOR THE PRODUCTION
OF ALUMINUM ALLOY THIN STRIPS
V. Yu. Bazhin,
N. A. Mityushov,
and A. V. Komarov
Translated from Novye Ogneupory, No. 8, pp. 40 – 42, August 2007.
Original article submitted January 23, 2007.
Computer tomography of refractories that are used in foundry systems for casting and rolling units in order to
prepare thin foil aluminum billets is performed. The question is considered of recycling refractory materials
with the aim of their further use in foundry equipment.
In a previous publication  use is considered for diffe
rent refractory materials in foundry systems for the produc
tion of thin sheet billets made of aluminum alloys in casting
and rolling units. The most favorable results are obtained
with use of Neco refractory plates from the American firm
Pyrotec. There is specific interest in a more careful study of
this refractory material with the aim increasing productivity
of equipment, including the quality of aluminum foil billets
and foils, and also possible recycling of refractory plates.
First a comprehensive petrographic study of Neco refrac-
tory plates was performed using microscopy in transmitted
and reflected light by means of computer tomography.
The foundry fittings are felt-like material whose basis is
a mineral fiber. In studying specimens by a fractographic
method (Fig. 1) transverse layering along a plate was re
vealed which predetermines the corresponding strength
anisotropy, i.e. a more uniform break along layers. Studies
have shown that the material consists entirely of amorphous
The nature of fibers, presence of glass beads and the re
fractive index are identical to a mullite-silica fiber. However,
there is a considerable amount of droplet-like ends of fibers,
and also fibers of considerable diameter compared with simi
lar refractory materials. The amount of aluminum oxide in a
glass fiber according to the glass refractive index is about
Between glass fibers there is a phase fulfilling the role of
a binder that exhibits good adhesion. It fills spaces between
fibers, but it is quite easily separated from them in preparing
immersion samples. Rarely it may be observed in individual
fibers. The refractive index of the binder is identical to so
dium metaphosphate NaPO
. According to chemical analysis
in a plate is only 23.5 mol.%, and about half the
total silica is in the binder. From this it follows that the
binder has a definite silica composition. Simple calculation
of the results of chemical analysis shows that in articles
65.5 wt.% (Al
) is contained in a fiber, and 31.9%
silica is in the binder. The deficiency in the results of analysis
of 2.6 wt.% is in the alkaline components of sodium and po-
tassium that increase the refractive index of pure quartz glass
(1.458) to the value observed and together with the silica
bring the mass of the binder to 36.5%. The binding glass-like
substance does not form a continuous filler for cavities be-
tween fibers throughout the whole volume of an article.
At the surface of the plate it is almost entirely fills the space
between fibers and within it there is local distribution as indi
vidual blotches. In the stage of studying the fracture surface
of a plate in reflected light by the dark field method it is pos
sible to see the presence of relatively coarse cavities in the
interwoven differently directed fibers. The binder is drawn to
areas of thinner fiber concentration.
Refractories and Industrial Ceramics Vol. 48, No. 4, 2007
1083-4877/07/4804-0271 © 2007 Springer Science+Business Media, Inc.
State Educational Institute of Higher Professional Education
(GOUVPO) UGTU-UPI, Russia.
Fig. 1. Fracture of a Neco plate across layering under a binocular