EFFECT OF CeO
ON THE CRYSTALLINE STRUCTURE
OF FORSTERITE SYNTHESIZED FROM LOW-GRADE MAGNESITE
and Wenyan Zhao
Translated from Novye Ogneupory, No. 7, pp. 34 – 38, July, 2013.
Original article submitted November 11, 2012.
The influence of CeO
on the crystalline structure of forsterite synthesized from low-grade magnesite and nat
ural silica is discussed in this paper. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were
used to study the crystalline structure and microstructure of each specimen, while X’ Pert Plus software was
used to determine each specimen’s lattice parameters. The bulk density, apparent porosity, water absorption,
and cold crushing strength of the specimens were determined in accordance with standards issued by the Min
istry. The results show that forsterite can be synthesized from low-grade magnesite and natural silica through
solid reaction. The synthesis process is facilitated by addition of the appropriate amount of CeO
. A defect
caused by Ce
O in active magnesia accelerates diffusion of the ions. The results obtained by XRD, SEM, and
property analysis show that the optimum addition of CeO
is 0.8 – 1.2%. The forsterite has a microstructure
with a homogeneous grain size, a bulk density of 2.15 – 1.18 g/cm
, apparent porosity of 29.5 – 30.1%, water
absorption of 13.5 – 14.0%, and cold crushing strength of 13.4 – 14.2 MPa.
Keywords: low-grade magnesite, natural silica, forsterite, CeO
Forsterite — crystalline magnesium silicate with the
chemical formula Mg
in the system MgO-SiO
classified as an olivine . The extremely low electrical con-
ductivity of forsterite makes it an ideal material for tunable
lasers. The material also has good refractoriness due to its
high melting point, low thermal expansion, good chemical
stability, and insulating properties that are exceptional even
at high temperatures . Forsterite used as a bioactive ce
ramic also exhibits superior fracture toughness, exceeding
that of bone implants [3, 4]. Different researchers have stud
ied the synthesis and characteristics of forsterite.
Nanocrystalline forsterite powder has been synthesized by a
citrate-nitrate technology that uses an aqueous solution of
magnesium nitrate, colloidal silica, citric acid, and ammonia
. Forsterite nanopowders have also been synthesized by a
sol-gel technology with the use of magnesium nitrate
hexahydrate and tetraethyl orthosilicate as the initial magne
sium- and silicon-bearing materials. Forsterite is also synthe
sized through a solid-phase reaction, which is preferable .
High temperatures and a long reaction time are needed to fa-
cilitate diffusion of the reagents used for obtaining forsterite
in the solid-phase reaction. Thus, mineralizers such as
rare-earth elements are often introduced to lower the
sintering temperature and improve the properties of the syn
thetic product [7 – 10]. The goal of the investigation being
discussed in this article was to synthesize forsterite from
low-grade magnesite and natural silica. We studied the effect
of an addition of CeO
on the crystalline structure of the for
sterite that was obtained. Compared to the standard technolo
gies used to synthesize forsterite, this investigation is innova
tive from the standpoint of the raw materials, process, and
technology that are being used.
The raw materials were powders of low-grade magnesite
(Haicheng, northeast China] and natural silica (Liaoyang,
northwest China). The low-grade magnesite was decom
posed over 1.5 h at 650°C and yielded active magnesia .
The cerium dioxide that was used in the investigation was an
analytical reagent. The forsterite contained 57.0 wt.% active
magnesia and 43.0 wt.% natural silica (SiO
> 98.0 wt.%) in
Refractories and Industrial Ceramics Vol. 54, No. 4, November, 2013
1083-4877/13/05404-0291 © 2013 Springer Science+Business Media New York
Department of High-Temperature and Magnesium-Resource En
gineering, Liaoning University of Science and Technology, An
Key Laboratory of New Ceramics and Fine Processing, Tsinghua
University, Beijing, China.
Department of Materials Science and Engineering, Jingdezhen
Ceramics Institute, Jingdezhen, China.