Science nano--ceramics materials have many advantages such as super-plasticity and highstrength which have significant effects on ceramic properties, studies on nano-ceramic materials have already been promising fields in materials science. Sintering and properties of nano-ceramics,prepaxation and characterization of nano-ceramic powders are reviewed in this paper.

Glass forming regions in the CdF₂-BaF₂-LiF system were determined through melting-quen-ching technique. The structure of 36CdF₂-34BaF₂-30LiF
(mol%) (CBL glass) was studied by X-ray diffraction and molecular dynamics simulation methods. The Cd atoms are six-, seven- and eightfold coordinated by fluorines.
The average Cd--F bond length is 2.29A. The Cd--Cd atom distance is about 3.52A for edge-sharing and 4.03A for corner-sharing in the MD-derived glass. The
glass structure can be discribed as a network made up of edge-sharing and corner-sharing [CdF_n] polyhedra which are partial linked by
Li⁺ ions. The role of Li⁺ ions in the fluoride glasses was discussed. It was proposed that Li⁺ may play the outpolarization effort in fluoride glass as
it does in the oxide one. This effort can play a positive role to the connectivity of the network based on the good glass formers. However, in the
glass based on the weak-bonded glass formers, the relative strong Li--F bond results in a decrease of its chemical durability as it does in the CdF₂-BaF₂-LiF system.

The sol-gel processing of acid-catalyzed tetraethoxysilane or tetrabutoxytitanate and MMA(monomeric methyl methacrylate), GPTMS(3-glycidyl propyl trimethoxisilane) to
produce laser dye Rhodamine B doped silica and titania organical modified sol-gel materials was systematically studied. Pseudo-ternary phase diagram was used to
outline the regions of stability of the sol-gel system on certain conditions. IR, TG/DTA, absorption and emission spectra were used to analyse the thermal,
machnical, optical properties of the sol-gel materials. It was found that TiO₂-Ormosils exhibited good thermal stability, mechanical and optical properties.

The Tb³⁺-doped zinc phthalate (ZnPht:Tb) phosphor was prepared by the solid phase reaction of zinc oxide and phthalic anhydride in the saturated water vapor
at 80～100℃. The crystal structure, emission and excitation spectra were determined. The dependence of the fluorescent spectrum properties on the Tb³⁺
ion concentration was investigated. The energy transfer mechanism from π,π* and n,π* excited states of Pht^2- radical to ⁵D₄ energy level of Tb³⁺
ion was revealed: (1) S₁(π,π*, n,π*)→(⁵H_j,⁵L_j)→⁵D₃→ T₁(π,π*, n,π*)→⁵H₄; (2) S₁(π,π*, n,π*)→ T₁(π,π*, n,π*)→⁵H₄.

The Nd.Zn:LiNbO₃ crystal was grewn under the best technique with czochralski method. Its direfractive gradient and the extinction rate were measured. The photo induced refractive change and the infrared transmission spectrum show that the crystal has good optical-damage-resistant.

A deep bulk trap level of SrTiO₃ grain boundary barrier layer (GBBL) capacitor material was found to be at about 0.21eV below its
conduction band by means of admittance spectroscopy. With temperature increasing from --150 to 10℃, the ε_eff protrusion and then the conspicuous dispersity of dielectric constant
were observed and explained. In terms of a combination of paraelectric behaviour of SrTiO₃ and a deep bulk trap effect, an equivalent circuit model involving the
deep bulk level was given. Based on the model, a reasonable cosistency of calculated dielctric constants with experimental data was revealed.

In dielectric, piezoelectric, and pyroelectric effects, the contributions of ferroelectricity, heteropolax charge, and homopolax charge can be studied sepaxately by using differential time domain spectroscopy method. For a same sample, by measuring the dielectric and pyroelectric spectra,the components of heteropolar and homopolar charges can be separated. In pyroelectric effect, the components of these charges have opposite signs.

Fine and active ZnO varistor powders were prepared by coprecipitation. Properties of the powders were demonstrated. Nonlinearity coefficients 50, high breakdown fields and large surge capability were achieved in varistor produced by these powders. The microstructure of varistors prepared by coprecipitation powders is uniformer than that of varistors prepared by conventionally prepared powders by mixed oxide technique.

V₂O₅ doping and complex V₂O₅-CuO doping BiNBO₄ ceramics were studied. The experimental results indicate that complex doping is more efficient in decreasing the sintering temperature,preventing exaggerated grain growth and improving the dielectric loss of the BiNbO₄ -based ceramics. This complex doping BiNbO₄ has more homogeneous grain size and higher density than that of V₂O₅-doped one, and their microwave properties are ε_r=44, Q=2000(3MHz).

The ionic interdiffusions for Nb⁵⁺, Ni²⁺, Zr⁴⁺ and Ti⁴⁺ ions in the PNN/PZT functionally gradient piezoelectric materials were investigated
as a function of diffusion temperature and time respectively. The ionic compositional distribution profiles were examined by electron probe microbeam analysis (EPMA),
from which the thickness of the interdiffusion layers were determined. Based on a diffusion model of the overlapped diffusion solute from thin slub, the numerical
simulation of the ionic concentration distributions for Nb⁵⁺, Ni²⁺, Zr⁴⁺ and Ti⁴⁺ ions was carried out by computer, which was in agreement
with the EPMA experimental result. The ionic diffusivities and apparent activation energies were estimated, and discussed.

PZN-based composite ceramics were prepared at lower sintering temperature by using fluorides and borosilicate glass as sintering aids. The correlation between the coexistence of two phases in
composite ceramics and sintering aids was studied. The results revealed that the crystal lattice defects caused by additives have detrimental effect on the coexistence of two phases in composites.
Incorporation of LiF into PZN crystal lattice promotes the reaction between two phases due to oxygen vacancies, while PZN-based composite ceramics with MgF₂ and borosilicate glass aids maintain
diphasic microstructure. PZN-based diphasic ceramics with X7R character were obtained at lowe sintering temperature by using borosilicate glass as sintering aids.

A model of combine toughening in the ceramics toughened with whiskers and phase-transforming particles is presented. The whisker toughening consists of crack bridging and
crack deflection. For transformation toughening, the shear effect is considered by using a shear factor, f, based on the dilatation contribution. Calculated results show
that there are interactions among crack bridging, crack deflection and transformation toughening. Crack bridging and crack deflection increase the transformation toughening
contribution, but transformation toughening decreases the contributions of crack bridging and crack deflection. Predictions of the toughness of SiC_w/ZrO₂(2mol%Y₂O₃)/Al₂O₃
based on the present model are showed to be in good agreement with the experimental results.

The residual stress in the particulate reinforced zircon matrix composites was characterizedby X-ray diffraction method. The relationship between the residual stress and toughening behaviorwas discussed on the basis of mechanical properties determination and microstructural observation.The results indicated that a bigger mismatch in the coefficients of thermal expansion of reinforcingparticle and matrix leads to a better toughening effect when the thermal expansion coefficientof particle (α_p) is higher than that of matrix (α_m). It was suggested that the main toughening mechanisms were the crack deflection and branching, which were attributed to the existence of residual stress. The increments of fracture toughness of composites calculated by residual stress field theory were in good agreement with the experiment values.

The effects of Fe content, carbon sources and the particle size of Ti and C on the SHS processes of Ti-C-Fe and structure charactristics of synthesized powders
were studied. It is shown that combustion temperature becomes lower and particle sizes of synthesized product become smaller with the increasing of Fe content and
the velocity of combustion wave is highest at 10wt% of Fe content. This is due to the effect of Fe liquid. The composition of TiC synthesized with graphite is more close
to the stoichiometric TiC, the size of TiC particles is larger and combustion temperature and velocity of combustion wave are higher than with carbon black. The
structure difference between the two kinds of carbon is responsible for the effect of carbon. Smaller Ti and C particle sizes do good to combustion synthesis of
the system. With the increasing of Fe content the combustion model becomes pulsating and spin combustion from steady combustion. The combustion reaction for the system
can’nt sustain if Fe content is higher than 60wt%.

Diamond-Like Carbon films were deposited on Si substrate from the mixture of C₂H₂ and Ar by r.f.-d.c. plasma enhanced chemical vapor deposition. The influence of deposition process
on the density and distribution of void in Diamond-Like Carbon films was systematically studied by low energy positron beam. The results indicate that the density of void
in Si substrate is the highest. A constant distribution of void was observed through the films, the density of void is lower, but the density of void in the surface layer
is higher. The density of void starts to increase near the interface and finally reaches the value of Si substrate. With the increasing of bias, the density of void in the
films and the depth of interface decrease at first, then increase, and then decrease. The density of void in the films increases monotonous with the increasing of
C₂H₂ percentage in the feed gas.

Hydroxyapatite coatings were made under different spray power using a Vacuum Plasma Spray System. The effects of spray power on characteristics
of hydroxyapatite coatings were investigated. In the experiment, X Ray Diffractometer and Scanning Electron Microscopy were used to detect phase compositions and
microstructures of as-received coatings. The results obtained indicated that, plasma spray power greatly effectsed the characteristics of the as-received
coatings. With the increase of spray power, hydroxyapatite content of as-received coatings decreased, showing the amorphorization of coatings was prompted. Also,
with the increase of spray power, the melt of hydroxyapatite was improved, the coatings with good microstructures were obtained.

Manganese-doped zinc sulfide and copper-doped zinc sulfide were prepared by a chemical precipitation method. The structures and sizes of these clusters were detected by X--ray diffraction.Photoluminescence measurements demonstrate some changes in optical property due to quantum size effect, such as excitation blue shift with size decreasing and faster decay time. The mechanisms of various luminescent centers in zinc sulfide cluster were discussed.

AlN powder was treated by shock waves with pressure of 9.8GPa. X-ray line broadening effect was found as the result of strain stored in shocked AlN lattice. Estimated
value of the strain is 2.85×10^-3, related dislocation density in shocked AlN powder is in the order of 10¹¹/cm², the energy stored in shocked
powder is 0.36Cal/g. The low temperature pressureless sintering process and thermal conductivity of shocked AlN powder with 6wt% additives were investigated. The results
showed that, the dislocation in shocked AlN powder can promote low temperature sinetring. In addition, it can remove Al₂O₃ from AlN lattices and achieve high thermal conductivity.
The energy stored in the shocked powder was released during the sintering process. The temperature of maximum shrink rate of shocked sample was about 25℃ lower than
that of unshocked one. The density of the shocked sample sintered at 1610℃ for 4h was 98% of its theoretical value, compared with 80% of the unshocked one. The
dislocation in shocked AlN powder can provide paths for the diffusion of oxygen through the grain in sintering process. So besides dissolution-reprecipitation, dislocation-
enhanced diffusion contributes its efforts to sintering, and it is beneficial for both sintering and achieving high thermal conductivity. The dislocation then can recover
in the later stage of the sintering process.

The DC bias field dependence characteristics of the PMN-PZN-PT relaxor ferroelectric ceramics were investigated. The experiments revealed that the DC bias field reduces the dielectric constant, increases the temperature of dielectric maximum, and supresses the frequency dispersion.Based on the concept of u frozen dipole" and " slow dipole ", These results were discussed.

Al₂O₃-Zro₂-SiC composites were prepared by RBAO technology and then fast-fired or conventionally-sintered. The materials obtained by both processes proved to have dense, fine-grained andhomogeneous microstructure, which gave rise to good mechanical properties. Fully dense and fiawfree materials were obtained after HIPing, therefore their properties were significantly improved.

A " sandwich" sintering method was employed for YSZ electrolyte membranes which were prepared by tape casting.Smooth and dense electrolyte membranes suitable for ceramic fuel cell were obtained. The microstructures and elctricaJ conductivity of sintered tape was determined.The experimental results showed that the sintering technique used is efficient for making electrolytemembrances, and their electronic conductivities were good enough for ceramic fuel cells.

The DTA curve of Ni50A120Fe30 (wt%) thermal explosion synthesis under linear heating rate was measured. The activation energy and reaction order of the SHS thermal explosion were calculated by using the Difference Quotient Method. The obtained results were essentially the saxne as that from the method of Combustion Wave Velocity.

Staring with the expressions of dielectric tensor, and using appropriate models to simplify these microscopic expressions, the calculated formulas of the Faraday rotation (θ_F) and the optic absorption coefficient (α) were obtained. The theoretic model of Bi-YIG magnetooptic properties and the pararnetric data-base were established. On the basis of above works, the system of computer aided design of Bi- YIG magnetooptic properties was developed, and the results were in good agreement with the experiment.

An effective processing method was studied to fabricate the translucent AlN ceramics. The AlN ceramics with 80mm diameter was prepared, and its optic property was measured to be transparent in wavelength of 0.2~2.2μm.