PREPARATION OF ZIRCONIUM, TITANIUM,
AND MAGNESIUM DIBORIDES BY METALLOTHERMIC REDUCTION
K. S. Campos,
G. F. B. Lenz e Silva,
E. H. M. Nunes,
and W. L. Vasconcelos
Translated from Novye Ogneupory, No. 10, pp. 37 – 43, October, 2013.
Original article submitted March 9, 2013.
Ceramic compositions based on carbides, nitrides, and borides are widely used as a result of their exceptional
resistance to wear, creep at high temperature, thermal shock, and oxidation. In order to provide these proper
ties, it is necessary to prepare a starting powder material structure characterized by uniformity and high spe
cific surface. Zirconium, titanium, and magnesium diborides are prepared in this work by metallothermic re
duction. The materials obtained are analyzed by x-ray diffraction (XRD), laser granulometry, scanning elec
tron microscopy (SEM), and energy dispersive spectroscopy (EDS). Thermodynamic calculations are carried
out using FactSage
thermochemical software and databases. It is observed that a significant part of the speci
mens obtained in this work have a high MgO content in their structure. A potential field of application of these
materials could be as antioxidants in periclase-carbon refractories since this industrial application does not re-
quire magnesium oxide removal. It is clearly established that magnesium, zirconium, and titanium diborides
exhibit good stability in reducing atmospheres.
Keywords: borides, refractories, metallothermic reduction, properties.
The main advantages of ceramic composites based on
carbides, nitrides, and borides compared with metals consists
of their exceptional resistance to wear, creep at high tempera
ture, thermal shock, and oxidation [1 – 3]. According to
Chorley and Lednor  in order to provide these properties it
is necessary to obtain a defect-free microstructure of uniform
starting materials with high specific surface.
It has been established precisely that metal elements of
the fourth, fifth, and sixth columns of the periodic system of
elements form a relatively large number of various com
pounds based on boron. They comprise a class of promising
materials for high-temperature areas of application in several
branches of industry, such as casting production and the re
fractory industry . TiB
is used extensively as ballistic ar
mour, cathodes, and thermocouple sheaths in electrolyzers
for melting aluminum by Hall-Heroult technology, crucibles
for molten metals, metal evaporation boats, and wear-resis
tant coatings for cutting tools [6 – 8]. ZrB
is a material of
special interest for use in reusable launch vehicles and
hyspersonic vehicles, particularly in sharp leading edges and
other surfaces at high temperature [9 – 11]. MgB
known as an important superconductor material [12 – 14].
Also worthy of attention is use of these materials as antioxi
dants for carbon-containing refractory materials [15 – 17].
Several methods are used for processing TiB
. Tani and Wada  prepared specimens based on
by means of carbothermal reaction between TiO
and C materials. Chamberlain, et al.,  prepared ZrB
specimens by pressureless sintering. Such sintering additives
as boron carbide and carbon are used in the process in order
to increase the sintering moving force. However, mechanical
stability of materials prepared in this way is lower than for
hot-pressed specimens . Giunchi  reported synthesis
by technology based on reactive infiltration of mol
ten Mg in boron powder briquettes. Self-propagating
high-temperature synthesis is also used extensively in pre
paring these materials [22 – 25]. This technology is based on
the principle that during ignition of starting reagents they are
formed spontaneously into products as a result of the exo
thermic nature of the reaction .
Refractories and Industrial Ceramics Vol. 54, No. 5, January, 2014
1083-4877/14/05405-0407 © 2014 Springer Science+Business Media New York
Department of Metallurgical and Materials Engineering, Federal
University of Minas Gerais, Brazil.
Department of Metallurgical and Materials Engineering, Univer
sity of São Paulo, Brazil.
Mg is in the second column of the periodic system of elements.