POROUS COMPOSITE CERAMIC MATERIALS
PRODUCED BY A SELF-PROPAGATING HIGH-TEMPERATURE
SYNTHESIS IN THE Fe
– Al SYSTEM
N. P. Tubalov,
O. A. Lebedeva,
and V. I. Vereshchagin
Translated from Novye Ogneupory, No. 9, pp. 40 – 42, September, 2003.
Mixtures of optimum composition for producing porous composite ceramic materials from industrial waste by
the self-propagating high-temperature synthesis (SHS) are developed. A flowchart of the SHS process is pro
posed. Mixtures based on iron oxide and aluminum oxide with the addition of 8 wt.% powdered aluminum
provide a route toward producing porous permeable materials from a waste of machine engineering (an alloy
steel scale), competitive with materials produced by powder metallurgy techniques.
Currently, porous permeable materials are in great de-
mand for various applications. Such materials can be pre-
pared by the so-called self-propagating high-temperature
synthesis (SHS) . Here of fundamental importance is the
proper choice of reactive precursor components. Metallic
powders conventionally used for preparing intermetallic po-
rous materials are expensive and not always readily avail-
able. We have proposed a SHS technique for preparing po-
rous metal-ceramic materials that is based on the use of
waste products of the engineering industry.
The industrial wastes were unmarketable metal oxides
(scale) and metallic powders . Preparation of porous mate
rials by the SMS method, apart from its importance for re
search, has also win-win implications for the environment.
Optimum mixture compositions were developed. The
starting materials were a scale of 18Kh2N4MA-grade steel
alloyed with 18% Cr, 2% Ni, and 4% Mo (the terminal char
acter A signifies a high-quality product), a fused electric co
rundum, and an aluminum powder. Phase composition of the
scale as analyzed by an x-ray diffraction method was:
58 – 58% iron oxides, 40 – 48% iron (ferrite), and
1.5 – 2.0% alloy element oxides. In the scale platelets, the
phase components were spread over the surface to a depth of
25 mm (as was ascertained by a polished section analysis);
the underlying material was ferrite. The steel was hot-treated
by a short-term technology (by which the scale was actually
produced), and the ferrite did not suffer from internal oxida
The fused corundum (a-Al
) was a fine-grained pow-
der (50 – 60 mm; MRTU 6-09-2046-644 Specifications); its
grain shape was angular or rounded. The ASD-1-grade alu-
minum powder (over 90% Al) was used, of rounded grain
shape (TU 48-5-22–87 Specifications).
The precursor materials were prepared by crushing scale
platelets in a KID-100 cone crusher; the fraction 63 – 125 mm
was separated using appropriate sieves and dried; corundum
and aluminum powders were sieved through a No. 0063 mesh
The proportion of mixture components was established
on condition that the thermal synthesis is conducted at
950 – 1050°C with no melting of the mixture components in
volved (by controlling the required amount of aluminum).
The concentration of components in the reaction mixture
was: 18Kh2N4MA steel scale, 46 – 50 wt.%; aluminum ox
Refractories and Industrial Ceramics Vol. 44, No. 5, 2003
1083-4877/03/4405-0343$25.00 © 2003 Plenum Publishing Corporation
Altai State Technical University, Barnaul, Russia; Tomsk
Polytechnical University, Tomsk, Russia.
USSR Patent No. 181168.
Fig. 1. An electron microscopic picture of a spalled scale platelet
(18Kh2N4MA steel; ´ 3000).