SCIENTIFIC RESEARCH AND DEVELOPMENTS
FABRICATION OF HIGH-DENSITY QUARTZ CERAMICS:
RESEARCH AND PRACTICAL ASPECTS.
PART 6. A COMPREHENSIVE STUDY OF THE PROPERTIES
OF BN-MODIFIED DENSELY SINTERED CERAMICS
E. I. Suzdal’tsev
Translated from Novye Ogneupory, No. 2, pp. 45 – 54, February, 2006.
Original article submitted August 10, 2005.
Results of a study of densely sintered quartz ceramics under conditions best suited to simulate the perfor-
mance of aircraft in flight are reported. The materials studied can find application in the design of aircraft
components exposed to high temperature, intense heat flow, and severe climate change.
STRENGHT AND ELASTIC PROPERTIES
OF BN-MODIFIED QUARTZ CERAMICS
At present, the ever-increasing requirements placed on
the components of quartz ceramics necessitate the study of
material properties characterized by rather large number of
parameters. The material properties should preferably be
studied and tested under conditions best suited to simulate
the actual conditions of aircraft employment. The behavior
of a material under extreme conditions makes it possible to
determine the range of its applicability in engineering com
ponents to ensure their reliable performance.
Applicability of a structural material is primarily deter
mined by the material’s strength properties. In our tests, the
bending strength s
was measured on an MRS-500 testing
machine using a three-point bending scheme; the compres
sive strength s
was measured on a PSU-10 press in con
formance with Russian Standard GOST 5458–75.
An essential feature of the BN-doped ceramic is its suffi
ciently high strength achieved at the early sintering stage.
Sintered at a temperature of about 1100°C, the material
up to 20 MPa, whereas in undoped ceramics it was
2.0 – 3.0 MPa. With increase in sintering temperature the
material undergoes rapid densification, the effective cross-
sectional area of the specimen increases, the framework
gains in bond strength, and at sintering temperatures of
1250 – 1275°C, the bending strength s
reaches a maximum
of 60 – 70 MPa.
The densely sintered ceramic with 0.5 – 1.0 wt.% BN
added shows no decrease in strength, whereas densification
degrades the strength properties of addition-free ceramic
(Fig. 1), which suggests the occurrence of cristobalite. This
Refractories and Industrial Ceramics Vol. 47, No. 2, 2006
1083-4877/06/4702-0101 © 2006 Springer Science+Business Media, Inc.
Tekhnologiya Research and Production Enterprise, Obninsk,
Kaluga Region, Russia.
0 8 16 24 32 40
Fig. 1. Bending strength s
of quartz ceramics plotted as a function
of porosity P: 1 – 5 ) ceramics with 0.5 wt.% BN added; 6 ) undoped
ceramic; 1 ) initial porosity 12.3%; 2, 6 ) 26.5%; 3 ) 31.3%; 4 ) 39.0%;
5 ) 46%.