Russian Journal of General Chemistry, Vol. 72, No. 8, 2002, pp. 1167 1169. Translated from Zhurnal Obshchei Khimii, Vol. 72, No. 8, 2002,
pp. 1247 1249.
Original Russian Text Copyright
2002 by Shilkin.
Reaction of Hydride Phases of Zirconium Intermetallic
Compounds with Molecular Nitrogen
S. P. Shilkin
Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow oblast, Russia
Received November 30, 2000
Abstract Reaction of hydride phases of zirconium intermetallic compounds with molecular nitrogen was
studied at 293 and 973 K and nitrogen pressure of 10 MPa. At 293 K, hydride nitride phases crystallizing in
the structural types of the initial hydride phases are formed in all cases, whereas at 973 K finely dispersed
heterophase mixtures of zirconium, molybdenum, and vanadium nitrides with 3d transition metals or mixtures
of zirconium nitride with vanadium, molybdenum, chromium, and manganese nitrides are formed.
In [1 4], we studied the reaction of binary and
pseudobinary zirconium intermetallic compounds with
hydrogen. We found that these compounds are not
broken down under the action of hydrogen but form
the corresponding hydride phases. The hydride phases
nitride phases by high-vacuum treatment are consis-
tent with this conclusion.
At the reaction temperature increased to 973 K, the
reaction occurs differently (Table 1). As the free ener-
gies of formation of zirconium, vanadium, molybde-
num, chromium, and manganese nitrides are close
under these conditions [8], in the hydride phases de-
rived from the intermetallic compounds ZrV , ZrMo ,
based on ZrV , ZrMo , ZrVFe, ZrVCo, ZrVNi, ZrCr ,
2
2
2
ZrMn , ZrMoFe, and ZrNi crystallize in the structural
2
types of the initial intermetallic compounds, and the
ZrCo crystal lattice (CsCl type) rearranges into an
orthorhombic lattice.
2
2
ZrCr , and ZrMn , the components of these phases are
2
2
nitrided simultaneously in the proportions correspond-
ing to the composition of the initial hydride phase.
If the free energy of formation of a metal nitride is
positive or strongly differs from those of nitrides of
the other metals constituting the intermetallic com-
pound, one or two metal components of a hydride
phase of a zirconium intermetallic compound can
react with nitrogen selectively. This is the case in
reaction of molecular nitrogen with metallic compo-
nents of the hydride phases derived from intermetallic
compounds ZrVT (T = Fe, Co, Ni), ZrMoFe, ZrCo,
and ZrNi. In the process, the specific surface area of
the solid phase noticeably increases owing to forma-
tion of nitride and metallic phases. It should be noted
that the unit cell parameters of these phases are in
good agreement with published data for the individual
compounds [9], suggesting the absence of noticeable
solid-state interaction between these phases at 973 K
We showed previously that the hydride phases
based on rare-earth and 3d transition metals are more
reactive toward nitrogen than the initial intermetallic
compounds, and the two-step transformation interme-
tallic compound
compound nitride phase can be performed easier
than the single-step transformation intermetallic com-
pound nitride phase [5].
hydride phase of the intermetallic
In view of this fact, we examined here the reaction
with molecular nitrogen of hydride phases of zirconi-
um intermetallic compounds crystallizing in the struc-
tural types of MgCu , MgZn , CsCl, and CrB. This
2
2
paper continues our previous studies [5 7].
The results of experiments on reaction of zirconium
hydride phases with molecular nitrogen (10 MPa) at
293 and 973 K are listed in Table 1. As seen from
and N pressure of 10 MPa.
2
these data, at room temperature, irrespective of the
chemical composition of the initial hydride phases and
structural type of their lattices, hydride nitride deriva-
tives are formed with the unit cell parameters virtually
equal to those of the corresponding hydride phases.
That is, uptake of a small amount of nitrogen affects
the structure of the hydride phases insignificantly.
The specific surface areas measured after removal of
hydrogen and nitrogen from hydride and hydride
Thus, reactions of hydride phases of binary and
pseudobinary zirconium alloys with molecular nitro-
gen can be described by the following equations:
2
93 K, 10 MPa
N2
ZrMmTHx
ZrMmTHxNy,
293 K, 10 MPa
ZrM THx
ZrN + T + mMN,
m
N2
M = V, Mo, Cr, Mn; T = Fe, Co, Ni; x = 4.7 1.1; y =
0.01 0.03; m = 1, 2.
1
070-3632/02/7208-1167$27.00 2002 MAIK Nauka/Interperiodica