Silica is an important structural and functional material, which is widely applied in the fields of aero craft, semiconductor, electronic telecommunication, and optical devices. However, the crystallization of cristobalite at elevated temperature has restricted its further application. In the present paper, current research results on the crystallization behavior of cristobalite in silica with different morphologies (bulk, powder, fiber and gel) and different silica matrix composites and different opinions on the mechanism of the crystallization behavior were reviewed. The mechanism of the crystallization behavior was recognized by the surface crystallization in the paper. In addition, the latest research results on the amorphization of cristobalite were also introduced.

Theoretical approaches (such as macroscopic thermodynamics phenomenological approach, microscopic transverse field Ising model and first-principles calculation) in dealing with size effect and predicts on critical size of ferroelectric phase transition are reviewed from two aspects, ferroelectric film and ferroelectric grain, respectively. Critical sizes of some ferroelectrics observed in experiments are summarized from 1950s. Some size effects of ferroelectric ceramics are introduced simply. Ferroelectric phase transitions of ferroelectric nanowires reported recently are narrated too. Finally, some problems in researching progress are pointed out.

The silicon mixture mechanically activated for 20h could combust in air. It was found that the burning of silicon powder occurred via two-stage self-propagating regime. The surface and center of the synthesized products are demonstrated to be with different features. On the surface of the product, α-Si₃N₄ is the major phase coexisting with minor Si₂N₂O and amorphous SiO₂, while in the center of the lump, loose grey powders are Si₃N₄ powders whose phase composition depends on the reaction conditions. The whole combustion process of silicon powders in air after mechanical activation approves the feasibility of silicon combustion in air. The qualitative discussion given shows the formation of Si3N4 instead of SiO₂ in air. Furthermore, the phase composition of product can be controlled by adjusting the composition of the reactant mixtures.

Vanadium doped Bi₄Ti₃O₁₂powder was prepared by a co-precipitation method and its phase evolution process, microstructure and sintering behavior were investigated. The results indicate that Bi4Ti3O12 crystalline phase with grain sizes of less than 100nm can be obtained by calcination of the precursor at 550℃, which is 250℃ lower than that of traditional solid reaction. The powder possesses a good sintering activity and the bulk density of sintered samples can reach 96% of theoretical value when sintering at 900℃ for 1h. In comparison to the material prepared by solid reaction, the sample made from the co-precipitation powder also has lower dielectric loss.

Hollow onion-like nanostructural carbon was constructed from acetylene carbon black with the aid of Fe, Co and Ni catalysts through the catalytic carbonization. The morphologies and structures of pristine carbon black and its carbonized products were investigated by using TEM, HRTEM, XRD and Raman spectroscopy measurements. The hollow onion-like nanostructural carbon mainly consists of quasi-spherically concentric graphite shells enclosing voids with interlayer spacing of 0.34nm. It is originated from the carbon-encapsulated metal nanoparticles by the dissolution-precipitation process between carbon and transition metal catalysts. The product catalyzed by Fe exhibits the typical and regular shape of onion-like nanostructural carbon and higher degree of graphitization. These imply that Fe possesses the better catalytic effect among these three metals.

The influence of calcining temperatures of the Fe/Mo/Al₂O₃ aerogel catalyst on its catalytic activity for synthesizing single walled carbon nanotubes(SWNTs) was investigated. The main research aspects were the physical and chemical changes of the catalysts under different calcining temperatures, the content of amorphous carbon, and the content and diameter and graphitization degree of SWNTs synthesized by the catalysts. The results show that different calcining temperatures will change the surface morphology of the catalyst and result in the crystallization of the Al₂O₃ support, which influences the growth of SWNTs. When it is calcined at 600℃, the aerogel catalyst has the highest catalytic activity, the content of amorphous carbon is as low as 1.7%, and the content of SWNTs is as high as 54.6%. SWNTs synthesized by the catalyst in the raw products have high quality, with narrow diameter distribution of about 0.86nm.

The mixture of SnO₂ powder and graphite was ground to ensure complete mixing, and was put into an alumina boat, then this boat was placed in the hot zone of the tube, heated from room temperature to 1100℃ and kept at this temperature for 2.5h in flowing argon. The X-ray diffraction analysis (XRD) indicates that the nanobelts are tetragonal rutile structure of SnO₂. Scaning electron microscope(SEM) and transmission electron microscope(TEM) observations reveal that the nanobelts are uniform. The selected-area electron diffraction analysis(SAED) demonstrates that the nanobelts are single crystal . The SnO₂ nanobelts might grow via a vapor-solid(VS) process.

High-density bat-like ZnO micro- and nanorods were prepared on Si(111) substrates by a thermal evaporation method using Zn powders and zinc acetate dihydrate (ZA) as the source materials. X-ray diffraction, field emission scanning electron microscope, transmission electron microscope, Raman scattering and photoluminescence were used to characterize the structural and optical properties of the obtained samples. The results indicate that the individual rod has four knots with different diameters, the rods are a high-quality single crystal with a few defects. The growth mechanism of the structures proposed reveals that oxygen partial pressures play an important role in the growth process. The shape of ZnO nanostructures can be controlled by adjusting oxygen flux.

The bioactive glass fibers in the system CaO-P₂O₅-SiO₂ were prepared by the sol-gel process. The composition and microstructure of the sol-gel derived bioactive glass fibers before and after immersion in the simulated body fluid (SBF) were investigated by inverted phase microscope, SEM and FTIR techniques. The mechanism of the calcium phosphates micro-crystals growth was discussed from the view of the crystallography. The results show that the bioactive glass fibers are discontinuous short fibers, and the short sol-gel bioactive glass fibers have a satisfactory shape and a high bioactivity owing to the rapid formation of downy A-type hydroxyl-carbonate-apatite (HCA) on the surface of bioactive glass fibers in SBF.

Scrap artificial graphite used as negative material of lithium ion batteries was firstly oxidized with 30% H₂O₂ at room temperature, and then modified by two methods: LiOH impregnation and molten Li₂CO₃ coating technique with N₂ protection. X-ray diffraction and X-ray photoelectron spectroscopy analysis show that these two modification methods can form Li2CO3 film as similar SEI film on the graphite surface, and increase oxygen content and oxygenic functional groups on the graphite surface. Compared with that of untreated artificial graphite, the charge capacities of treated samples with oxidation and similar SEI formation increase from 255.5mAh/g to 323mAh/g upward, and the reversible capacity decreases a little in the first fifty cycles, keeping 317mAh/g. It proves that surface oxidation and similar SEI formation treatment can reduce lithium ion consumption, restrain decomposition of solvent and electrolyte, and improve coulombic efficiency.

Stoichiometric Mg doped LiFePO₄/C cathode material was synthesized through a templatesolid state reaction in an inert atmosphere using magnesium lactate as dopant and part of carbon source. Effects of Mg²⁺ doping on the electrochemical and physical performances of the cathode materials were investigated. At 1/3C discharge rate, the secondly reversible specific capacity of the Mg-doped LiFePO₄/C is nearly 20mAh/g higher than that of the undoped one. After 20 cycles, the capacity of the former is 162.1mAh/g, 22mAh/g higher than that of the latter. Impedance R ct of the Mg-doped material is 120Ω, while that of the undoped material is 180Ω. The tap density of Mg-doped material is
also improved by 0.229g·cm^-3 compared with undoped material.

The LiFePO₄/C composite cathode materials for lithiumion batteries were synthesized by a solid state reduction method. The crystalline structure, morphology of particles, and electrochemical performance of the sample were investigated by -ray diffraction, scanning electron microscope, charge-discharge test and cyclic voltammetry. The results show that the composite synthesized at 700℃ has a simple pure olivetype phase with small particles, and uniformly distribution of gain sizes, and shows the best electrochemical performances with 1^st discharge specific capacity 150.3mAh/g and 20 th discharge specific capacity retention ratio 99.2% at 0.1C rate. It also shows good rate capability with 131.4mAh/g, 122.1mAh/g at the high rate of 1.0C and 2.0C, respectively. With the excellent characteristic to resist overcharge, this composite can retain its microstructure even after long time overcharge, but it is vulnerable to overdischarge.

Spherical morphology LiNi_1/3Co_1/3Mn_1/3O₂ as a cathode aterial of lithium ion batteries was successfully synthesized by an ultrasonic spray pyrolysis method. The effects of different precursor solution on the morphology of particles were investigated. The reasons of morphology difference were analysed by using the process mechanism of spray pyrolysis. In addition, the impacts of various post reatment sintering time on electrochemical performances of the samples were characterized. Experimental results show that the cathode material synthesized by ultrasonic spray pyrolysis using nitrate as precursor solution, followed by sintering at 900℃ for 6h, exhibits excellent electrochemical properties. In the voltage range of 3.0--4.3V, initial discharge capacity of the sample is 157.7mAh · g^-1 and its capacity retains 146.6mAh·g^-1 after 40 cycles.

Three organic-inorganic hybrid phosphors were synthesized by a surface coordination method with SrAl₂O₄:Eu²⁺, Dy³⁺ powder and maleic anhydride,oleic acid and 2,2’dipyrical ligand respectively, and characterized by means of IR, SEM, XRD, fluorescent spectra and water resistance experiments. The results show that Sr²⁺²⁺ on the surface of SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor is coordinated with O and N atoms of maleic anhydride and oleic acid and 2,2’dipyrical ligand respectively. The crystal structures, the shapes and positions of excitation and emission peak of coated phosphors are the same as that of uncoated phosphors, but after coordination encapsulation, the relative luminous intensity and the afterglow life are decreased, and the roughness of crystal structure is increased, and the stability in water is improved. The best ligand is maleic anhydride. The luminous intensity and afterglow life of the phosphors coordinated with maleic anhydride are less 3％ and 5％ respectively than that of the uncoated phosphors.

Eu³⁺ doped Ca₂SnO₄ powder samples were prepared by a solid-state method and their formation mechanism and luminescent properties were investigated. When the starting powder mixture of CaCO₃ and SnO₂ (2:1) is calcined at 1250℃, the unstable intermediate phase CaSnO₃ is developed, which then reacts with CaO to form the final product Ca₂SnO₄. The excitation spectra of Ca _2-xEu_xSnO₄ show broad Eu ³⁺-O^2- charge-transfer bands with the peak locations changing from 274nm to 292nm by increasing Eu³⁺ concentrations (x=0.01--0.15). Under UV excitation, the Ca₂SnO₄:Eu³⁺ phosphor exhibits novel red emission at about 618nm which is assigned to the ²D-⁷F₂ electric-dipole transition. In addition, the weak emission transitions from the higher ⁵D₂ and ⁵D₁ excited states can be observed at low Eu³⁺ concentrations because of the low multiphonon relaxation probability. The spectral shape of the Eu³⁺ emission of Ca₂SnO₄:Eu³⁺ is similar to that of its isostructural compound Sr₂CeO₄ :Eu³⁺ , however, the red emission from the former is much stronger than that from the latter.

Calcium montmorillonite (Ca-MMT), sodium ontmorillonite (Na-MMT) and acid-activated montmorillonite (AAM), and their Cu ²⁺ -exchanged ontmorillonites (Cu-MMT), Cu*Ca-MMT, Cu*Na-MMT and Cu*AAM, were used to study the adsorptive activity on Aeromonas hydrophila. The Zeta potentials of MMTs and A. hydrophila are all decreased with increasing pH, and those of Cu-MMTs are increased with increasing pH and transformed from
the negative to positive value when pH=4--6. AAM, Na-MMT and Ca-MMT show some ability to reduce bacterial plate counts by 36.5％, 20.1％ and 14.3％, respectively. The Cu*AAM, Cu*Na-MMT and Cu*Ca-MMT reduce the bacterial plate counts by 99.6％, 93.1％ and 87.4％. The extent of bacterial adsorption onto MMTs is decreased with increasing pH. However, the bacterial adsorption onto Cu-MMTs is decreased with increasing pH and increased with increasing pH when pH>5.0. The study of desorption of Cu2+ by washing with physiological saline for 24h reveals that the washing solutions don’t show a significant reduction of the bacterial counts, while the washed Cu-MMTs retain their full antibacterial activity. The mechanism by which bacterial counts are reduced may involve the enhanced affinity of Cu-MMT for Aeromonas hydrophila and the antibacterial activity of Cu²⁺.

The La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ(LSCF) composite oxide was prepared via combined EDTA-citrate complexing process with concentrated nitric acid treatment. The treatment would result in the self-combustion of solid state precursors at low temperatures. The effect of preparing conditions on LSCF’s catalytic properties was investigated by using decomposition of peroxide hydrogen as the model. The FT-IR results of the solid state precursor and the pH values of aqueous solution of it were studied to determine the mechanism of the thermal decomposition of organic in the precursor and of the self-combustion process. Moreover, XRD was employed to characterize the crystal structure of LSCF calcined at higher temperatures. The study shows that the treatment can depress the growth of crystallite and improve the
catalysis for decomposition of peroxide hydrogen. Of the all samples, the LSCF-40-900 has the highest activity to the decomposition of peroxide hydrogen.

The twin defects in Ce:YAP were investigated by using synchrotron radiation topography and etch figures. The results show that the twins are {101} and {121} types, and the exchange of neighboring lattice parameters is considered to be the intrinsic factor for twining. Based on such analysis, the twin structure model was established. Otherwise, the growth experiment results show that the abrupt change of growth rate during shoulder formation tends to cause twining.

Prismatic single crystal γ-MnOOH was synthesized by a hydrothermal method through oxidizing Mn(CH₃COO₂ with HMnO₄ at 150℃. The advantage of oxidizing agent HMnO₄ is that no other metallic ions coming into the product structures. The synthesized samples were characterized by XRD, SEM, TEM, HRTEM and TG. It is found that the formation process of single crystal γ-MnOOH includes two primary evolution stages: (1) the γ-MnOOH whiskers are initially formed, and (2) the whiskers grow to prismatic single crystal γ-MnOOH by an adsorption-growth process, (111) plane grows faster than other planes, because the surface energy of each crystal plane is different, the different growth rate makes the whiskers changed to prismatic crystal. The hydrothermal reaction time is the major factor that influences crystal morphology. TG results show that the single crystal γ-MnOOH is transferred to MnO₂ at 350℃.

Fluorescence properties of Er³⁺:⁴I_13/2～⁴I_15/2 transition were measured in a tellurite glass. The fluorescence spectra, fluorescence intensities and lifetimes were investigated as a function of erbium ion concentration. It is found that there are intense radiation trapping and concentration quenching effect in erbium-doped tellurite glasses. With the increase of erbium ion concentration, fluorescence spectrum broadens significantly and its main emission peak shifts from 1532nm to 1556nm as a result of the changed relative intensity of each spectral component caused by radiation trapping. Fluorescence intensity decreases strongly with higher erbium ion concentration due to concentration quenching effect caused by cooperative upconversion among Er³⁺ ions. Also, radiation trapping and concentration quenching cause fluorescence lifetime increase at first and then decrease rapidly with the increase of Er³⁺ concentration.

The infiltration of carbon fiber preforms was studied by microwave pyrolysis chemical vapor infiltration technique, CH₄
as the carbon source gas, and N₂ as diluent gas, at 1100℃ and methane partial pressure of 10kPa with residence time of 0.05,0.1,0.15 and 0.2s, respectively. The textures of samples were observed, the densification rules of microwave pyrolysis CVI were analyzed by densification rate and radial--direction density distribution with different residence time. Results show that carbon fiber preforms can be densified from inside to outside at 1100℃ for 90h, with gas residence time of 0.15s, the carbon/carbon composite has a higher bulk density of 1.70g·cm^-3. Simultaneously, polariscope images show that the textures of the pyrocarbon change from low-textured to medium-textured with the extending of residence time.

Dry spinning performance of PCSsolution and self crosslinking process of the PCS fiber as-spun were studied by viscosity, gel content and XRD techniques. The composition, structure and mechanical properties of SiC fibers were also characterized. Results show that the optimum spinning viscosity of PCS/xylene solution is 18.0-22.0Pa·s, self crosslinking process of the PCS fiber by dry-spun begins at 250℃ during pyrolysis process, and finishes at 550℃ to form a network structure which does not melt or dissolue. The oxygen content of the final SiC fibers is decreased to about 3.6wt%. SiC fibers prepared by dry spinning have a better β-SiC microcrystalline structure and show better oxidation resistance than those prepared by the oxidation curing.

Polycarbosilane was used as the preceramic for matrix formation and 2D layered 0°/90° fabrics as the reinforcement to fabricate C/SiC composites. The effect of pyrolysis temperature and slurry concentration on the properties of the composites was systematically studied. The results show that the flexural stress increase with the increase of both pyrolysis Temperature and slurry concentration. The matrix distribution in fiber bundle is quite homogeneous, but some small pores still exist after eight pyrolysis cycles. When the composite is pyrolyzed at 1100℃, β-SiC begins to form in the matrix. The flexural stress and toughness reach 232MPa and 10.50MPa·m^1/2, respectively. Observation of long pull-out fibers in the fracture surface demonstrates a toughened fracture behavior of the composite.

MoSi₂-SiC composite was successfully prepared by Si melt infiltration into Mo+C preforms. The crystal grain size of the resultant matrix is 150-600nm, and the size of SiC phase produced is 30-160nm which disperses homogeneously in the matrix. The strength of the composite is 214.8MPa, the toughness is 4.1MPa·m^1/2, these mechanical properties are higher than that of single phase MoSi₂. TEM results show lots of stacking faults, some dislocations, and twins existing in the composite.

60vol%SiC_p/Al composites with high relative density of 99% were fabricated by spark plasma sintering (SPS). The consolidating mechanism of SiC_p/Al composites by SPS was analyzed on two aspects: (1) the adjustment of sintering parameters; (2) the effect of electric field. The results indicate that the consolidating procedure of SiC_p/Al composites
by SPS is mainly dependent on the proper adjustment of temperature, pressure and heating-rate which make Al melt and adhere SiC particles without spraying out of the graphite dies; no obvious spark appears during the sintering, which may result from the weak electric field.

Domestic silica fiber reinforced minicomposites were fabricated by slurry infiltration (including silica sol, silica slurry and silicon nitride slurry). And their strength distributions were analyzed with two parameter Weibull distribution. Then the goodness of fit of the strength distribution was conducted by the Kolmogorov test. Meanwhile, the strength distributions of treated silica fibers were also studied. The results show that two parameter Weibull distribution can be used to express
the strength distribution of silica fiber and its minicomposites. It also suggests that the strength of the fiber decreases sharply after heat treatment, and the dispersity of the strength is increased. With the same heat treatment conditions, the strength of minicomposites infiltrated with silica sol is higher, and the Weibull modulus is also increased, while the
strength of minicomposites infiltrated by silica or silicon nitride slurry is lower.

The microstructure and dielectric properties of V₂O₅-doped BaTiO₃-Y₂O₃-MgO ternary system were studied. SEM shows that V ions can promote grain growth of BaTiO₃ based ceramics, but decrease the density of sintered ceramics. XRD indicates that V-doped
samples have pseudocubic structure and the solubility limit of V is more than 1.0mol%. The results show that V can increase the intensity of Curie peak and improve the temperature stability of dielectric constant, because of the formation of core-shell-grains with thin shell layer, which is attributed to the fact that V ions can effectively inhibit the diffusion of Y and/or Mg ions into BaTO₃ grains and change the distribution of doping ions in the grains. Moreover multivalent V ions can reinforce the nonreducibility of this system, and the insulation resistivity increases to 10¹³Ω·cm and dielectric loss decrease to 0.63% consequently. The high performance materials with dielectric constant of 2600 satisfying the X8R
requirement is achieved when 0.1mol% V is added.

The doping effects of NiNb₂O₆, CaZrO₃ and MnCO₃ on the dielectric properties and breakdown voltages of fine grain BaTiO₃ systems were studied. NiNb₂O₆ can shift the Curie temperature and broaden it, and makes contributions to double peaks; CaZrO₃ may improve the temperature coefficiency characteristic greatly and enhance the withstand voltage; adding MnCO₃ can restrain the overgrowth of particles, which can decease the dielectric dissipation and improve the withstand voltage greatly. With adding 2.5mol% NiNb₂O₆, 1.5mol% CaZrO₃ and 0.1mol% MnCO₃, a kind of MLC ceramic with low frequent and high voltage can be got, which also meets X8R requirement, and its dielectric properties are as follows: ε≥2600, Δ C/C _20℃≤±15% (-55℃-- +150℃), tgδ≤0.7%, E_b≥15kV/mm.

A La_0.67Ca_0.33MnO₃(LCMO)/MgO granular composite system was fabricated by a chemical route. The grain size of the parent LCMO powders can be altered by controlling the initial sintering temperature. It shows that electrical transport and magetoresistive properties of the composite system strongly depend on the MgO content and initial sintering temperatures. For the samples with T_s1=1100℃, the insulator-metal transition can be observed only in pure LCMO and the x=1mol% composite. However, For the samples with T_s1=900℃, the insulator-metal transition can still be observed in the x=7mol% composite in which the maximal low field magnetoresistance (H=0.3T) is enhanced from 5% in pure LCMO to 27%. SEM analysis shows that
linking between LCMO grains is weakened with increasing MgO content or elevating the initial sintering temperature. The experimental results were discussed in terms of the spin polarized tunneling mechanism.

Single crystalline 3C-SiC thin films were grown on Si(111) at different substrate temperatures by solid source molecular beam epitaxy (SSMBE). Their structure, morphology and chemical component and the influence of the substrate temperature were investigated by reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atom force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). The results indicate that the sample grown at substrate temperature of 1000℃ exhibits the best crystalline quality. For higher substrate temperature, there will be more huge voids on sample surfaces, and the large mismatch of thermal expansion coefficient between SiC and Si can cause more dislocation when samples are cooled down to room temperature from high substrate temperature. For lower substrate temperature, the deviation from stoichiometry will occur, which is responsible for the deteriorations of crystalline quality.

GaN thin films were prepared by direct current (DC) planar magnetron sputtering on Si and SiO$_2$. The films were characterized by X-ray diffraction (XRD), Raman, Fourier Transform Infrared Spectroscopy (FTIR), photoluminescence (PL) and UV-Vis spectra. XRD and Raman spectrum show that the films are amorphous. Fourier infrared absorbance spectrum shows
that the main absorbance is Ga-N stretching vibration. 360nm ultraviolet emission is obtained at room temperature. UV-Vis result shows that the optical band gap of the films is 3.74eV, which is consistent with photoluminescence spectrum result.
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TiO₂ films with Pt distributing in bottom layer(PT) or uniformly(PP) were prepared by a sol-gel method through alternate dip-coating process. The photoelectrochemical behaviors of the films were measured by a three-electrode system, and the dye-sensitized solar cells (DSSC) with these films as anodes were assembled to investigate the photoelectric conversion capacities. The results show that the photocurrent of PT film is higher than that of TT and more enlarged by ethanol addition into the electrolyte as the holes’ capture agent. The above phenomena can be explained based
on the separation of photogenerated carriers and photoholes’ accumulation in the surface layer. Due to photoholes’ accumulating in the surface, the excited electrons can transfer to TiO₂ film more easily. The short-circuit I_sc and the open-potential V_oc are increased obviously.

TiO₂/SnO₂ composite films were prepared on a slide glass with a sol-gel method at low temperature. The influence of different dip-coating times of SnO₂ layers on the photocatalytic activity of TiO₂/SnO₂ composite films was investigated. In addition, the mechanism of the photocatalytic activity enhancement of TiO₂/SnO₂
composite film was also analyzed. The results show that the photocatalytic efficiency of TiO₂ film is enhanced by using SnO₂ layer as a substrate. Since the conduction band (CB) of SnO₂ is lower than that of TiO₂, and the valence band(VB) of SnO₂ is higher than that of TiO₂, electrons transfer from TiO₂ to SnO₂, while holes oppositely diffuse into the SnO₂ layer . Thus, the charge recombination is suppressed more efficiently, and more holes can reach the TiO₂ surface to cause oxidation
reaction. This is believed to be the main reason for the photocatalytic activity enhancement of the TiO₂ film photocatalyst.

A SiC coating was prepared on carbon/carbon (C/C) composites by a two-step technique of pack cementation and CVD processes to prevent these composites from oxidation. SEM, EDS and XRD were applied to analyze the surface and cross-section morphologies, element distribution and phase composition of the coating, respectively. The results show that a transitional layer with gradient distribution of Si and C content is formed between the SiC coating obtained by pack cementation process and C/C substrate, and the compact coating prepared by CVD process effectively fills the pores of the coating by pack cementation. The coating made by the two-step technique exhibits excellent oxidation protective ability. The weight loss percentage of the coated C/C composites is only 2.01% after oxidation in air at 1500℃ for 60h. The weight loss of C/C composites is primarily due to the reaction of C/C and oxygen diffusing through the microcracks in the coating during the thermal cycle between 1500℃ and room temperature.

Thin films of zirconium oxide were deposited on Si (100) substrates by reactive radio frequency magnetron sputtering. The films were characterized by high-resolution transmission electron microscope (HRTEM) and atomic force microscope (AFM) to investigate the variation of surface morphology and microstructure with oxygen partial pressures and deposition temperatures, respectively. With the increase in oxygen partial pressure ratio from 7% to 100%, the surface roughness approximatively linearly increases, and the phase transition of the films is a-ZrO₂ (amorphous)→ a-ZrO₂ with a little m-ZrO₂ (monoclinic)
→m-ZrO₂+t-ZrO₂ (tetragonal)→m-ZrO₂. For deposition temperatures ranging from room temperature to 550℃, the phase transition of the films is a-ZrO₂ (below 250℃)→m-ZrO₂ with a little a-ZrO₂ (450℃)→m-ZrO₂ with a little t-ZrO₂ (550℃).
According to the results on the structure and surface morphology of ZrO₂ thin films, the dependence of deposition temperature on surface evolution and its physical mechanism are discussed also.

A new nanosmooth potassium tetratitanate film was prepared on glass substrates by a sol-gel method using Ti(n-OC₄H₉)₄ and CH₃COOK as precursors. The surface structure of the film was analyzed by atomic force microscope (AFM). The crystal growth of potassium tetratitanate was characterized by TG and XRD. The photocatalytic decomposition of octadecyltrichlorosilane (OTS) based self- assembled monolayers(SAMs) formed on K2Ti4O9 films was studied by using contact angle analysis. The results show that the films consist of flat particles with the ratio of diameter to height about 11. The root
mean square roughness (RMS) of the films measured on an area of 2μm×2μm in AFM images is 4.1nm. Densely packed OTS-SAMs similar in quality to those on TiO₂ are formed on K₂Ti₄O₉. K₂Ti₄O₉ efficiently decomposes OTS-SAMs under UV irradiation in air.

HA coatings were deposited onto TiAl6V4 substrate by microplasma spraying (MPS) as well as by atmospheric plasma spraying (APS). The morphology, phase compositions and crystallinity of the coatings were studied by means of optical, scanning electron microscopy and X-ray diffraction. The results show that the decomposition of HA can be significantly reduced during MPS than during APS. In addition to HA, only β-TCP and amorphous phases form during MPS. MPS coating crystallinity is clearly influenced by spray distance. Shorter spray distances (<80mm) result in high crystallinities, which are much higher than those of APS coatings. But with a spray distance of 130 mm, the coating crystallinity is very low. β-TCP, α-TCP, TTCP, CaO and amorphous phases form during APS. Compared with APS coatings, MPS coatings are less decomposed during spraying, due to the less overheating of HA particles.

In initial sintering stage of the porous (porosity≥50%) matrix impregnated fully with molten carbonate (46wt% electrolyte) and sintered under the cell stacking pressure, the sintering brought about the rearrangements and slips of powder particles by which the maximum pore diameter altered into a smaller one. Its maximum pore diameter and slip rate were smaller and oppositely higher respectively than those in the matrix impregnated with the less (5wt%) electrolyte and sintered under the ordinary pressure. The cell stacking pressure facilitated the rearrangements and slips of powder particles, but effectively suppressed and diminished defect developments in the sintered matrix. Porosity in the matrix increased, micro-pores altered into bigger ones, mean pore diameter increasing and pore-size distribution becoming narrowly with sintering time by the synergetic action of the rearrangements of powder particles and its accompanying mechanisms. As indicated above, the sintering behaviors and the alteration of some physical properties with sintering time in the porous matrix are different from those in traditional ceramics. So the rearrangement of powder particles dominates over the sintering mechanisms of the porous matrix, its sintering model conforms to the trapezium model.

After electrodeposion of Ni-W-P alloy on Cu sheet, nano-crystalline TiO2 film modified Ni-W-P electrode was prepared by a sol-gel method. Scanning electron microscope (SEM), X-ray diffraction (XRD) and cathodic polarization curves were used to characterize the surface morphology, microstructure and catalytic activity for hydrogen evolution reaction (HER) of TiO2/Ni-W-P electrodes. Effects of the sintering temperature and the thickness of TiO2 film on the structure and performance of TiO2/Ni-W-P electrodes were researched. The results clearly demonstrate that the TiO2/Ni-W-P electrode annealed at 550℃ for 1h has the best photoelectrocatalytic activity for HER, and the overpotential for HER decreases about 140mV under illumination. The TiO2 film with average grain size of 7nm is mixed crystal structure containing anatase and rutile crystal phases.