Borides, including TiB₂, ZrB₂, HfB₂, B₄C and BN, have good physical and chemical properties, which have been proposed for a variety of applications in extreme environments, such as ultra-high temperature, super-hard and super-hydrophobic. However, the engineering applications of these borides are still restricted by their poor sinterability and unsatisfied material properties including low fracture toughness. In regard with the advantages of pressureless sintering in preparation of ceramics, the main factors that affect the pressureless sintering of borides are discussed. The pressureless sintering technology of borides represented by oxygen removing mechanism is summarized. In consideration of the low toughness of borides, the microstructure tailoring methods represented by platelet toughening and nano phase reinforced are emphasized. At last, the methods for preparing textured boride ceramics are also briefly introduced.

Water-quenching technique was used to evaluate the thermal shock behavior of the SiC-SiC joints joined with Na₂O-B₂O₃-SiO₂ glass solder. The microstructure of the side view of the interface and the fracture surface of the joints after quenching were analyzed. The influence of the quenching temperature and quenching cycles from 150℃ to cool water on the residual strength of the specimens were investigated. At the quenching temperature of 150℃, the residual strength of the joint decreased to (152±28) MPa due to the propagation of the microcracks in the interlayer caused by the thermal residual stress after one thermal cycle. At the quenching temperature from 150℃ to 320℃, the cracks seemed to be in subcritical state, and the residual strength was kept around 140 MPa. When the quenching temperature was increased to 420℃ or higher, the cracks propagation became more serious, and the strength decreased to (32±8) MPa rapidly. Moreover, the residual strength was hardly affected by the quenching cycles from 150℃ to cool water which meant that the joined specimens possesed good thermal shock resistance behavior at this temperature.

Considering the difficulty of sintering and leachability of alumina-based ceramic core, different contents of silica were added to the specimens. The porous alumina-based ceramic core was prepared using the dry pressing processes. The effect of different contents of silica, sintering temperature and sintering time on the properties of the alumina-based ceramic core were investigated. The results indicated that the linear shrinkages of the specimens sintered at 1500℃ and 1600℃ for 2 h were nearly the same. When the sample was sintered at 1700℃ for 2 h, the bending strength was decreased and the porosity was increased due to the evaporation of SiO₂. The shrinkage, bending strength, porosity and bulk-density of the specimens sintered at 1500℃ were invariable when the holding time exceeded 4 h. The sample sintered at 1500℃ for 2 h had linear shrinkage of 1.1%, bending strength of 63 MPa, the porosity of 35.5% and bulk-density of 2.29 g/cm³, which was hopeful to be the core candidate materials in high temperature application.

La_0.8Sr_0.2MnO₃ smart thermal control coating was obtained by coating technology using La_0.8Sr_0.2MnO₃ powder as base material and Al(H₂PO₄)₃ as binder, respectively. The La_0.8Sr_0.2MnO₃ powders were prepared by solid state reaction. La_0.8Sr_0.2MnO₃ powders were characterized by XRD and EDS. The variable thermal emittance of La_0.8Sr_0.2MnO₃ thermal control coating was measured at the temperature range of -100℃ to 100℃ by the steady-state emissometer. In addition, the solar absorptance of as-prepared coating was surveyed. The results showed that homogeneous, micro-sized La_0.8Sr_0.2MnO₃ particle can be obtained through heat treatment at 1200℃ for three times. The variation of the thermal emittance from -100℃ to 100℃ of as-prepared coating by coating technology could be more than 0.3, which is close to that of La_0.8Sr_0.2MnO₃ ceramic tile. This kind of smart thermal control coating is a promising candidate material in satellite for active thermal control technology.

A PEO-LATP/LAGP composite electrolyte for lithium batteries was designed and prepared. Uniformly composite electrolyte membrane with thickness of 20 μm was obtained by assembling Li_1.4Al_0.4Ti_1.6(PO₄)₃ (LATP) or Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) as ceramic substrate and PEO as binder. Highest room-temperature conductivities were achieved for the sample prepared with w(ceramics):w(PEO)=7:3. Electrochemical analysis showed that the conductivity reached 0.186 mS/cm for PEO-LATP and 0.111 mS/cm for PEO-LAGP. Cycling performances of  170 mAh/g was obtained for the first discharge capacity of the Li/composite electrolyte/LiCo_1/3Ni_1/3Mn_1/3O₂ cell. Sharp decrease of cycling capacity was observed for the cell using PEO-LATP membrane. The cycling performance of the PEO-LAGP based cell was greatly improved with 150 mAh/g remained after 10 cycles.

Titanium, lithium and carbon source compounds were mixed by ball milling firstly, then the slurry was spray dried to prepare spherical precursor. The porous spherical spinel Li₄Ti₅O₁₂/C powders were synthesized by calcining the precursor. XRD, SEM, TEM, BET testing and determination of the electrochemical properties show that the prepared Li₄Ti₅O₁₂/C powders are in form of spherical particles which is composed of nanocrystals. The specific surface area of Li₄Ti₅O₁₂/C powders is as high as 39.5 m²/g. The initial discharge specific capacities of the Li₄Ti₅O₁₂/C anode reach 172.2, 168.2 and 153.6 mAh/g at 0.1C, 1C and 5.0C rates, respectively. The Li₄Ti₅O₁₂/C anode also exhibits excellent cycle performance. The porous Li₄Ti₅O₁₂ material coated by carbon displays excellent high rate performance and cycling stability.

Spherical Ni_0.8Co_0.1Mn_0.1(OH)₂ precursors with a high tap-density and a narrow size-distribution were synthesized via coprecipitation using NaOH and NH₃·H₂O as the precipitation and complexing agents. Spherical LiNi_0.8Co_0.1Mn_0.1O₂ particles were then prepared by sintering the mixture of this precursor and LiOH·H₂O. The prepared materials were characterized by XRD, SEM, TEM, TGA/DSC and galvanostatically charge/discharge tests. The results indicate that secondary spherulites of the precursors are formed by aggregation of crystals but not by elongated crystals. The reaction time shows a significant effect on the morphology, size-distribution and tap-density of the precursor. The LiNi_0.8Co_0.1Mn_0.1O₂ powders calcined under 750℃ for 16 h exhibit a spherical morphology with the highest tap-density (2.98 g/cm³) and the largest initial discharge capacity (202.4 mAh/g). More than 92.3% of the capacity is retained after 40 cycles. In addition, the cell delivers a discharge capacity of 174.1 mAh/g at 3C rate.

Samples of (Ce_0.8Y_0.2-xNd_xO_1.9)_0.99(ZnO)_0.01 (0≤x≤0.2) were synthesized by EDTA-citrate complexing method. The samples were characterized by thermogravimetric, X-ray diffraction, thermal expansion measurement and AC impedance spectroscope, respectively. The effect of Y/Nd dopant ratio on the electrical properties of materials was studied particularly. The results show that all samples prepared by EDTA-citrate complexing method have single cubic fluorite structure. The relatively dense (Ce_0.8Y_0.2-xNd_xO_1.9)_0.99(ZnO)_0.01 series samples can be obtained after sintered at 1350℃ with 1mol% ZnO. Among all the samples, (Ce_0.8Y_0.05Nd_0.15O_1.9)0.99(ZnO)_0.01 shows the highest ionic conductivity of 58.79 mS/cm measured at 750℃. The thermal expansion coefficients of all samples are in the range of (11.83-12.30)×10^-6 /K.

The Effects of ragid additive of MnO₂, soft additive of, Nb₂O₅ and double additive of Cr₂O₃ on the crystallographic phase and temperature stability of Pb(Mn_1/3Sb_2/3)_0.05Zr_0.47Ti_0.48O₃ (PMSZT5) piezoelectric ceramic were studied. The results show that the pure perovskitic structure is obtained after calcined at 900℃. With these additives increasing, the amount of tetroganal phases decrease, and the morphotropic phase boundary(MPB) is correspondingly shift to the rhombohedral phase. Considering the effects of ion doping on the electric properties and temperature stability comprehensively, the PMSZT5 ceramic doped with MnO₂ has more excellent temperature stability than that doped with Nb₂O₅ and Cr₂O₃. A well-situated property of relative dielectric constant ε₃₃^T/ε₀ (1560), piezoelectric constant d₃₃ (350 pC/ N) and planar coupling factor K_p (0.63) are obtained for the composition of PMSZT5+ 0.1wt% MnO₂. Accordingly, the average temperature coefficients of f_r, K₃₁ and d₃₁, the PMSZT ceramics are 72×10^-6/℃, -0.027%/℃, 0.100%/℃ at the temperature range of -25℃ to 80℃.

Lead-free K_0.5Na_0.5NbO₃(KNN) piezoelectric ceramics were prepared by conventional solid-state reaction technique and sintered through conventional and hot-pressing sintering process respectively. The effects of sintering method and annealing temperature on the microstructure, morphology and density of KNN ceramics were investigated. The crystallographic structure of KNN ceramic was investigated by X-ray diffraction (XRD) and the fractured microstructures of sintered ceramics were characterized by scanning electronic microscope (SEM). The results show that all specimens exhibit pure perovskite structures. However, compared with the sample prepared with conventional sintering, higher relative density (greater than 98%), smaller grain size (0.6 μm) and lower tanδ (≤2. 8%, 1 kHz) are obtained in the KNN ceramics sintered through hot-pressure sintering process, meantime various particle sizes and densities of KNN ceramics can be obtained by selecting suitable annealing temperature.

The (Ba_1-xSr_x)La₄Ti₄O₁₅ (x=0.8-0.95) ceramics were prepared by the solid-state reaction method and the phase compositions, crystal structures and microwave dielectric properties were investigated. The results show that the (Ba_1-xSr_x)La₄Ti₄O₁₅ ceramics have the main phase of SrLa₄Ti₄O₁₅ and the second phase of SrLa₈Ti₉O₁₅. The SEM images indicate that the Ba_0.2Sr_0.8La₄Ti₄O₁₅ ceramic with dense microstructures has grain sizes of about 10-20 μm and clear crystal boundaries. The grain shapes of the (Ba_1-xSr_x)La₄Ti₄O₁₅ ceramics change with increasing x values, and the pores in the samples increase. (Ba_1-xSr_x)La₄Ti₄O₁₅ ceramics with x=0.8 possesses excellent microwave dielectric properties, listed as follows, the dielectric constant ε_r =40.86, the quality factor Q×f≈62806 GHz, and the temperature coefficient of resonant frequency τ_f =-20×10^-6/℃. The monotone increases of the dielectric constant εr and the quality factor Q×f of the ceramics with increasing Ba²⁺ contents, mean that the proper substitution of Ba²⁺ for Sr²⁺ can improve microwave dielectric properties of the (Ba_1-xSr_x)La₄Ti₄O₁₅ ceramics.

Ba_0.75Sr_0.25TiO₃ film was epitaxially grown on a (001) LaAlO₃ substrate using single-target pulsed laser deposition. The microstructure of the epitaxial film was investigated by high-resolution transmission electron microscope (HRTEM), and the formation mechanism of microstructural defects was explored. It was shown that misfit and threading dislocations existed in the epitaxial Ba_0.75Sr_0.25TiO₃ film. Apart from the dislocations, two different kinds of antiphase boundaries, straight and zig-zagged, were observed. For misfit dislocations, they were formed due to the lattice mismatch between LaAlO₃ and Ba_0.75Sr_0.25TiO₃ which could dissociate into several partial dislocations. For the threading dislocations, it was found that their dissociation usually coexists with stacking faults. The formation mechanism of the antiphase boundaries is attributed to the terrace or step on the surfaces of LaAlO₃ substrate. If the nucleation site is just on the terrace, straight antiphase boundaries will be formed. However, if the nucleation site is not just on the terrace but a little far away from the terrace, zig-zagged antiphase boundaries will be produced. The results could shed light on the microstructural defects in other perovskite epitaxial films.

Using pulsed laser deposition technique, the multiferroic BaTiO₃/La_2/3Sr_1/3MnO₃ composite bilayer films were epitaxially prepared on (001) oriented LaAlO₃ single crystal substrate. The measurements of electric and magnetic properties showed that the composite structure possessed superior ferromagnetic and ferroelectric properties, its relative dielectric constant and ferromagnetic curie temperature were 263 and 317 K, respectively. The magnetoelectric voltage coefficient for the bilayer films at room temperature was around 176 mV/A, which was at least one order of magnitude higher than the previous reported in the same structures. The corresponding interface coupling parameter k was about 0.68, which indicated a better interface coupling between ferromagnetic and ferroelectric layers.

The local electronic structures of Zn_0.97Mn_0.03O和Zn_0.67Mn_0.33O thin films prepared by a molecular beam epitaxy (MBE) at 200℃ were investigated by soft X-ray fluorescence spectrometer of beamline 8.0.1 of the Advanced Light Source (ALS). The special interest can be given to find the relationship between the electronic structure of Mn and magnetic properties of our samples. Analysis of the integral intensity ratio of Mn L₂ to L₃ emission lines (I(L₂)/I(L₃)) from resonant and nonresonant Mn L_2,3 X-ray emission spectra (XES) indicates that ferromagnetism (FM) is related to the free d charge carriers in the film. For ferromagnetic Zn_0.97Mn_0.03O sample, the majority of Mn atoms are incorporated at Zn substitutional sites and the film shows strong Coster-Kronig (C-K) transitions due to a large amount of free charge carriers available around Mn atoms. Both non-localized d charge carriers as itinerant electrons and 4s electrons from interstitial Mn obtained by Ruderman-Kittel-Kasuya-Yosid (RKKY) calculations can induce the ferromagnetic exchange interaction. However, the disappearance of FM in Zn_0.67Mn_0.33O sample can be explained in terms of the existence of MnO clusters leading to a reduction in the number of free charge carriers.

ZnO nanowire arrays were grown on the Si(111) substrates coated with 1 nm Au catalyst by plasma assisted molecular beam epitaxy (MBE) through Vapor-Liquid-Solid (VLS) growth mechanism at low temperature. Field-emission scanning electron microscope (FE-SEM) reveals that ZnO nanowire arrays grow densely and vertically to the substrate surface with the average diameter of 20-30 nm. The structure properties of ZnO nanowires are measured by X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM), the results clearly show that the ZnO nanowire exhibits a typical wurtzite structure with c-axis (002) preferred orientation and good crystal quality. The diffraction peaks can be indexed to a hexagonal structure of bulk ZnO with cell constants of a =  0.325 nm and c = 0.521 nm. The spacing of the lattice fringes along the c axis of the ZnO nanowire is 0.52 nm. The room temperature photoluminescence (PL) spectrum shows that the ZnO nanowire arrays possess good photoluminscent properties with strong near band edge excitonic UV emission around 380 nm and weak defect-related emission in the visible region of 475-650 nm.

In order to deeply understand the influence of oxalic impurities on the optical properties of anodic aluminum oxide (AAO), AAOs prepared in oxalic acid solution were investigated by the temperature programmed desorption combined with mass spectrograph (TPD-MS), thermogravimetric analysis (TGA), differential thermal analysis (DTA) and photoluminescence (PL) techniques. The thermal weight loss of AAOs was monitored in the temperature range between room temperature (RT) and 1200℃ and analyzed quantitatively. The analysis results indicate that the desorption of H₂O, CO and CO₂ molecules and the decomposition of oxalic acid impurity occur below 402.2℃, therein water desorption is the main reason for the weight loss. In the temperature range of 402.2-866.7℃, the incomplete decomposition of aluminum oxalate occurs and gives birth to CO and CO₂ with CO as the major component. The drastic decomposition of aluminum carbonate and oxalate take place in the temperature range of 866.7-1022.9℃, CO₂ is the main product. According to the TGA results and the molar ratios of CO in the desorption products, the content variation of oxalic impurities intermingled in bulk AAOs is obtained with the change of temperature. At last, the correlation of the optical property for AAOs with the concentration of oxalic impurities and oxygen vacancies (F⁺) is proposed.

Quasi-monodispersed SnO₂ microspheres were successfully prepared by microwave solvothermal method at 180℃ for 30 min, using PEG-6000 (0.12 mmol) as template, SnCl₄·5H₂O and urea as raw materials. The as-prepared samples were characterized by XRD, SEM, TEM, and FT-IR. Futhermore, the photoluminescence (PL) property of the products were investigated by PL spectroscope. The results show that the SnO₂ microspheres with diameter about 1.3 um are self-assembled by nanocrystals. The surface of microspheres is smooth and their morphology is well preserved after calcined at 400℃ for 2 h. The peak at 550 cm^-1 in FT-IR spectra may belong to the surface vibration mode, which due to the surface structure changes of the samples. A strong and broad band (320-450 nm) is exhibited in the PL spectra for uncalcined product. However, the intensity of emitting band is greatly decreased after calcination, which proves that the lattice defects of the products are of great importance to the near band edge emission.

The sodium borosilicate glass containing Bi₂O₃ nanocrystals was synthesized by employing both Sol-Gel and atmosphere control methods. Morphology and microstructure of the Bi₂O₃ nanocrystals doped in the sodium borosilicate glass were characterized by means of X-ray powder diffraction (XRD), X-ray photoelectron spectroscope (XPS), transmission electron microscope (TEM), energy dispersion X-ray spectra (EDX), scanning transmission electron microscope (STEM), high-resolution transmission electron microscope (HRTEM), and selected-area electron diffraction (SAED). Meanwhile, the third-order nonlinear optical absorption properties of the Bi₂O₃ nanocrystals glass were investigated by means of the femtosecond open-aperture Z-scan technique under the different excited light intensities at a wavelength of 800 nm. The results show that the Bi₂O₃ nanocrystals are formed in the sodium borosilicate glass matrix, with dimension less than 10 nm. Moreover, the transformation from saturable absorption to reverse saturable absorption will occur with the increase of the excited light intensities in the glass. Furthermore, the calculated magnitude of the third-order nonlinear susceptibility χ⁽³⁾ ranges from 10^-19 to 10^-18 m²/V² in the glass. The results indicate that the glass exhibits the excellent nonlinear optical properties, which have potential application in the field of nonlinear optics such as optical limiters, etc.

Resistive random access memory (ReRAM) is one of the most promising candidates for next generation high speed nonvolatile memory devices. Bi₂O₃ thin films were deposited on heavily doped silicon wafer by RF magnetron sputtering, and the crystalline structure of the Bi₂O₃ thin films were characterized by XRD. The resistive switching characteristics of the Au/Bi₂O₃/n⁺Si/Al structure and the dependence of the ReRAM behavior on the thickness of the Bi₂O₃ thin films were studied. XRD analysis shows that the Bi₂O₃ thin films have good crystalline quality with (201) preferential orientation, while I-V curves results indicate that Bi₂O₃ thin films exhibit reversible and steady unipolar resistive switching behaviors. It is further found that the forming voltages, set voltages, and reset voltages depend linearly on the thickness of Bi₂O₃ thin films, and for the device with the thickness of 31.2 nm, these three threshold voltages are all below 4 V, which meet the need of low voltage operation of the memories.

Highly dispersed gold nanoparticles incorporated mesoporous zirconia thin films were synthesized through an easy deposition-precipitation method using urea as precipitator. The resultant composite thin films presented an enhanced off-resonant third-order optical nonlinear susceptibility of 10^-10 esu measured by Z-scan technique at 1064 nm. The enhanced optical nonlinearity of the composite thin films was attributed to the high dispersion of the gold nanoparticles and the high linear refractive index of the zirconia matrix.

Presently activated carbon is used as an adsorptive material for chemical and biological warfare agents. It possess excellent surface properties such as large surface area, fire-resistance and plenty availability, but has disadvantages such as its heavy weight, low breathability (after adsorption of moisture) and disposal. In this paper, we propose to utilize novel electrospun polymeric nanostructures having zeolites as catalyst materials. In this respective, the electrospun polymer nanofibers would serve as the best possible substitutes to activated carbon based protective clothing applications. This is the first in the literature that reports the integration of these types of catalysts with nanofiberous membranes.?Electrospinning of cellulose/polyethylene terephthalate (PET) blend nanofibers has been carried out. Zeolite catalysts (Linde Type A and Mordenite) for the detoxification of nerve agent stimulant-paraoxon, were prepared due to their relative simplicity of synthesis. The catalysts were then coated onto nanofiber membranes and their morphology was confirmed using SEM. This is the first report on the coating of nanofibers with zeolites and their successful demonstration against nerve agent stimulant. The UV absorption spectra clearly show the detoxification ability of the functionalized fibers and their potential to be used in textiles for protection and decontamination.