Abstract: Si3N4-Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders
by the liquid phase sintering. The mass loss, relative density and average grain size increase with
increasing sintering temperature. The average grain size is less than 500nm when the sintering
temperature is lower than 1700°C. Friction coefficient is from 0.35 for sintering temperature 1650°C to
0.74 for 1600°C when the composites were worn by silicon nitride bearing ball. High hardness of 21.5GPa
and relative wear resistance of 32 were observed at a sintering temperature of 1600°C. The wear surface
are very smooth and no grooving and subsurface fracture, which indicates that they are worn slightly.
Abstract: The SiOC foam ceramics were prepared using polyurethane sponge and polysiloxane as raw
materials. The effects of the pyrolysis temperature, the concentration of polysiloxane solutions, and the
content of SiC nano-powder on compression strength of the SiOC foam ceramics have been investigated
respectively. The optimum compression strength of SiOC foam ceramics is obtained at the pyrolysis
temperature of 1250°C and the concentration of solution PSO of 0.8 g/ml. Adding SiC nano-powder into
PSO can effectively increase compression strength of samples, and the maximum compression strength,
20.8 MPa, is obtained when the content of SiC nano-powder is 5 wt%. Microstructural study reveals that
the foam ceramics have an open, uniform and interconnected porous structure with high porosity of 80%.
Abstract: The feasibility of synthesizing MgSiN2 powders through combustion synthesis process is
demonstrated. A self-sustained combustion wave can be initiated with or without the addition of active
diluent. The wave propagation resulted in a product with several secondary phases in addition to the main
phase MgSiN2 when the combustion reaction was initiated without the addition of active diluent. As the
active diluent was used in the reactant mixtures, the amounts of the secondary phases were decreased. The
effect of active diluent addition on the phase composition and morphology of the final product was
discussed. Furthermore, the use of MgSiN2 crystal seeds in the reactant mixtures was also investigated. It
is found that the active diluent can facilitate the nitridation reaction. The experimental results showed that
changing the experimental parameters such as the amount of active diluent and the MgSiN2 crystal seeds
could optimize the fabrication of MgSiN2 powders through combustion synthesis process.
Abstract: SiBCN microtubes were prepared for the first time by spinning a low molecular weight
preceramic polymers of boron-modified polyvinylsilazanes into green fibers ~30 m in diameter which
were subsequently thermolyzed under a nitrogen atmosphere. Hollow SiBCN ceramic fibers black
colored, of flexible form, ~20 m in diameter and 0.8GPa in tensile strength were produced.
Abstract: Orthorhombic boron nitride film is prepared on Si(100) substrate by radio frequency plasma
enhanced pulse (Nd:YAG) laser deposition (RF-PEPLD) in Ar-N2 gas system, assisted with substrate
pulse negative bias -150v, substrate temperature of 500°C and deposition time of 30 minutes. The phase
compositions of the film are characterized by Fourier transform infrared (FTIR) spectroscopy,
glancing-angle X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM).
The results show that high quality orthorhombic boron nitride film has been prepared. A layer structure
growth mechanism of orthorhombic boron nitride phase upon RF-PEPLD is discussed in this paper. A
thin layer h-BN  is deposited before depositing o-BN and h-BN mixed phase, then o-BN percentage
composition of the BN film becomes creasing.
Abstract: In this paper microcrystalline CBN abrasives are prepared with CBN powders and vitrified
bond additives by pressureless sintering method. Mechanical properties of the products are measured by
using single particle compressive strength tester and three-point bending strength tester. The effects of
vitrified bond additives, the CBN powders particle size and the sintering temperature on the performance
of microcrystalline CBN abrasives are investigated. The microstructure characteristics of
microcrystalline CBN abrasives are examined. The results showed that the performance and
microstructure of microcrystalline CBN abrasives are significantly influenced by particle size of CBN
powder and the addition amount of vitrified bond.
Abstract: The B4C/BN nanocomposites were fabricated by hot-pressing sintering of the B4C/BN
nanocomposite powders at 1850oC for 1h under the pressure of 30MPa. The composite powders with
the microstructure of B4C particles coated with nano-sized BN particles were prepared by the
chemical reaction of H3BO3 and CO(NH2)2 on the surface of B4C particles at high temperature. The
microstructure investigation of the nanocomposites sintered samples showed that the nano-sized
h-BN particles were homogenously distributed in the B4C matrix. With the increasing content of
h-BN, the density of the B4C/BN nanocomposites decreased gradually; the fracture strength and
fracture toughness of the B4C/BN nanocomposites decreased gradually, the strength and toughness of
the B4C/BN nanocomposites with the h-BN content of 10wt% and 20wt% achieved high values. The
Vickers hardness of the B4C/BN nanocomposites decreased remarkably with the increasing content of
h-BN, while the machinability of the B4C/BN nanocomposites was significantly improved. The
B4C/BN nanocomposites with the h-BN content more than 20wt% exhibited excellent machinability.
Abstract: A series of samples of hexagonal boron nitride-aluminum nitride (10-90, 15-85, 20-80, 25-75,
30-70wt.%) ceramic composites were prepared by spark plasma sintering in a nitrogen atmosphere at
1650 °C-1800 °C for 5min. Different amounts of CaF2 were added as sintering aids. The effects of CaF2
and sintering temperature on densification and dielectric properties were discussed. The addition of CaF2
enhances relative dielectric constant and loss tangent of the samples. The increase in sintering
temperature promotes the densification and decreases the dielectric loss tangent. When being sintered at
1700 °C, the relative density, dielectric constant and dielectric loss tangent of the sample with 15wt.%BN
are 98.04%, 7.15 and 6.31×10-4 respectively.
Abstract: In this study, micro patterns were formed on the developed AlN-hBN composites using powder
blasting techniques, which have been considered as one of the most appropriate micro machining methods
for hard and brittle materials such as ceramics. To achieve the objective, first, material properties of the
developed AlN-hBN composites were evaluated according to the variation of h-BN contents. And, a
series of required experiments were performed, and the results were analyzed. As the results, it was
investigated that the machiniability of the developed AlN-hBN composites increased with the increase of
the h-BN contents in the composites. From the experimental results, it was possible to determine optimum
blasting conditions for micro pattern making on the developed AlN-hBN composites.
Abstract: In this study, the machining characteristics of developed AlN-hBN composites were
investigated in the end-milling and precision lapping processes. To achieve the objectives, material
properties of the developed AlN-hBN composites were evaluated according to the variation of hBN
contents. And, required experimental works were performed to investigate the machining characteristics
of the composites. First, the machiniability of the composite was evaluated in the end-milling process
under various cutting conditions, such as spindle speed, feederate, and depth of cut variations. Also,
generated micro cracks caused by the cutting process were investigated via SEM photographs. Next,
precision lapping experiments were performed under various conditions, and the results were estimated.