YAG is not only one of the most important solid laser crystals, but also a promising scintillation material. Since it comes out, the studies of defects in YAG crystal have played key roles on the improvement and development of crystal properties. As a special kind of defect in the YAG and LuAG crystals, anti-site defects exert crucial influence on the carrier transportation and other properties. In this paper, the type and the origin of the anti-site defects in the YAG and LuAG crystals, as well as the mechanism of their effects on the crystal properties are described. Also, how to detect and inhibit the anti-site defects in the YAG and LuAG crystals are discussed.

The first realization of transparent alumina ceramics among all advanced ceramics expand a new research field of advanced ceramics. The application of transparent alumina is also successful, such as arc tubes for high intensity discharge lamps. Fruitful results in theory research and processing optimization are made with the purpose of enhancing transmittance of alumina ceramics over the past half-century. In this paper, the effects of the intrinsic factors on the transmittance of alumina ceramics are studied. New methods and technology developments of transparent alumina reported in recent years are reviewed, mainly including sub-micrometer grain transparent alumina, oriented grain transparent alumina and single crystal alumina prepared by solid state crystal growth. The future tendency of transparent alumina ceramics are?also represented.

Cerium doped yttrium pyrosilicate Y₂Si₂O₇:Ce(YPS) single crystal was obtained through the floating zone method. The scintillation and thermoluminescence (TL) properties of YPS:Ce were studied. The scintillation and optical properties of YPS:Ce crystal were characterized by light output, decay time and transmittance. Its potential application prospect as scintillation material was also evaluated. It was noticed that the decay time of YPS:Ce was about 30.16 ns, which was the fastest value in the cerium doped silicate scintillators. The traps in YPS:Ce were studied through TL spectrum. Three traps were detected in the temperature range of 300-500 K, corresponding to three trap in YPS:Ce sample. The physical parameters of these traps (including energy level, frequency factor) were determined through fitting the 2D (temperature-luminescence intensity) TL curve. Combined with 3D (temperature- wavelength-luminescence intensity) TL spectra, the TL mode of YPS:Ce sample was proposed.

A new material, Zn-containing derivative from SrBi₂Nb₂O₉, was synthesized by multi-step ion-exchanges with H⁺/(BiO)⁺, TMA+ (tetramethylammonium ions)/H⁺, and Zn(NH₃)₄²⁺/TMA⁺ step by step. X-ray diffraction (XRD) patterns exhibite the difference in the layered structures among the precursor SrBi2Nb2O9 (SBN), its protonated product (HSN), and Zn-containing derivative (ZSN). The compositional analyses reveal the extraction of most of the bismuth atoms and the loss of a small part of the strontium atoms after protonation. The UV-Vis (ultraviolet-visible) absorption edge of the Zn-containing derivative shifts markedly to high energy compared with that of the precursor and its protonated product.

The influences of Bi₂O₃-B₂O₃ glass additives on the microstructure and nonlinear electrical properties of ZnO-Bi₂O₃-TiO₂-based varistor were investigated. SEM images show that low melting Bi₂O₃-B₂O₃ glass can help to increase ZnO grain size and refine microstructure with uniform grain size distribution at 900℃ through liquid phase sintering mechanism, whereas the grain size decreases with increasing ZnO-B₂O₃ glass addition resulting from non-melting ZnO-B₂O₃ glass pining the ZnO grain boundaries. The varistor ceramics with 2wt% Bi₂O₃-B₂O₃ glass addition own best nonlinear electrical properties with voltage gradient E_1mA=124.9V/mm, nonlinear coefficient α=46.2, leakage current density J_L=0.2μA/cm². For Bi₂O₃-B₂O₃ glass doped varistor, kinetic exponent nB and apparent activation energy QB are only 2.15 and 146.2kJ/mol which are much lower than that of ZnO-B₂O₃ glass doped varistor. The results reveal that Bi₂O₃-B₂O₃ glass doping is more effective in improving the microstructure and electrical properties of ZnO-Bi₂O₃-TiO₂-based varistor than ZnO-B₂O₃ glass doping.

The TiO₂ nanocrystal particles were prepared by low-temperature method. Firstly, hydrolysis of reactants was promoted with microwave radiation aid, then crystallization could be facilitated through the process of the second microwave radiation or aging in water bath. The characterization results show that the shape of TiO₂ nanocrystal is sphere or short column, which are all in pure anatase phase. The kinetic studies indicate that the anatase TiO₂ growth can be described as the twice order kinetic equation and the apparent activity energy is 59.47 kJ/mol with two-step microwave radiation, while the kinetic equation is conformed to the third order and the apparent activity energy is 19.44 kJ/mol with ageing process. The above comparison proves that the nanocrystal TiO₂ would grow faster in short time with the two-step microwave radiation at low temperature.

The nanosized CeO₂-ZrO₂ solid solutions were prepared by modified Sol-Gel method with Ce(NO₃)₃·6H₂O and ZrO(NO₃)₂·2H₂O as starting materials. The effects of different Ce/Zr molar ratio and calcination temperature on the particle size, crystal type and reducibility were studied to obtain optimal preparation condition. CeO₂-ZrO₂ solid solution was characterized by XRD, SEM and TPR measurements. Results show that the highest specific surface area of CeO₂-ZrO₂ solid solution is 92m²/g while Ce/Zr molar ratio is 3: 1. CeO₂-ZrO₂ solid solution prepared by modified Sol-Gel method is fluorite structured. TPR results show that CeO₂-ZrO₂ solid solution calcined at 450℃ has good catalytic reducibility. Catalytic properties are estimated through a fix-bed reactor under atmospheric pressure. CeO₂-ZrO₂ solid solution with Ce/Zr molar ratio of 3: 1 show higher catalytic activity and selectivity to ethanol steam reforming reaction than those of CeO₂ and other molar ratio CeO₂-ZrO₂ solid solution. Both reducibility and heat stability of CeO₂ can be improved with the addition of ZrO₂.

Bi₂(Zn_1/3Nb_2/3)₂O₇ based ceramics were prepared by a traditional solid phase reaction method. The effects of substitution Na⁺ for Bi³⁺ and Ni²⁺ for Nb³⁺ on the sintering and dielectric properties of Bi₂(Zn_1/3Nb_2/3)₂O₇ based ceramics were investigated. The sintering temperature of the substituted samples dropped to 870℃ from  960℃. At -30℃-+130℃, the dielectric relaxation peak with a broad temperature region is obviously observed and two relaxation peaks appear when the substitution of Ni²⁺ reaches 0.2. Then, with the increasing of substitution, the temperature of the permittivity maximum shifts to higher temperature and the activation energy involved in the relaxation processes increases and the distance between two relaxation peaks become longer. Defect dipole and distortion of crystal lattice theories are used to explain the dielectric relaxation of Na-Ni doped Bi₂(Zn_1/3Nb_2/3)₂O₇ ceramics.

BaTiO₃/multi-walled carbon nanotubes (MWCNTs) composite was synthesized by an efficient solvent-thermal route. Transmission electron microscope images clearly indicate that the surfaces of the MWCNTs are uniformly decorated by well-crystallized BaTiO₃ particles with diameters of 15-30 nm. The result of Electromagnetic (EM) wave absorption properties analysis, determined by the EM parameters, shows that the reflection loss (RL) in the BaTiO₃/MWCNT composite is higher than that occurring in pure MWCNTs or BaTiO₃, which resulted from the better matched characteristic impedance and enhanced complex permeability in the high frequency. The maximum RL of –37.5 dB in the BaTiO₃/MWCNT composite is obtained at a frequency of 10.4 GHz and the absorption range is under –10 dB in the frequency range of 9.6–13.1GHz with the absorber thickness of 2 mm.  BaTiO₃/MWCNT/PAN hybrid fibres, derived from a PAN solution containing 10 wt% BaTiO₃/MWCNT composite, were prepared by the electrospinning process. The results of XRD and SEM indicated that both the structure of  BaTiO₃/MWCNT composite and the morphology of PAN changed little after the hybrid process. BaTiO₃/MWCNT composite has the well compatibility with PAN matrix.

In order to reduce the dielectric loss and retain the high dielectric constant, CaCu₃Ti₄O₁₂ ceramics were prepared by coprecipitation method. The thermal decomposition process of precursor was studied by TG/DTG and FTIR. The CaCu₃Ti₄O₁₂ phase structure was confirmed by X-ray diffraction. The dielectric spectra and I-V characteristics were measured at room temperature. Ca-Cu solutions with different pH values were used. It is found that when the pH value of Ca-Cu solutions is 5.1, the dielectric constant of the CaCu₃Ti₄O₁₂ ceramics is still high and dielectric loss reaches the lowest. At room temperature, the dielectric constant is 1.4×10⁴ and the dielectric loss is 0.037, when the frequency is 1kHz. The precipitation of each element, microstructure and dielectric properties of ceramics are affected by the pH value of Ca-Cu solution. Thus the pH value of Ca-Cu solution is one of the key points to decrease dielectric loss and improve dielectric constant of the CaCu₃Ti₄O₁₂ ceramics.

Continuous silicon carbide (SiC) fiber with carbon coating was fabricated by three-stage chemical vapor deposition (CVD) on W filament heated by direct current (DC), using CH₃SiCl₃ as gaseous reactant for SiC as well as C₂H₂ for the outmost carbon coating. Young’s modulus and tensile strength of the fiber were tested at room temperature, while Weibull distribution was conducted for evaluation of the tensile properties of the fiber. Fracture morphology, phase structure and microstructure of the fiber were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM). Results show that the SiC fiber, from W core to outside, exhibits a W/SiC interfacial reaction layer with a thickness of about 0.35μm, two layers of SiC and an even carbon coating. XRD pattern indicates that the SiC layers are all composed of β-SiC, which corresponds to diffraction angle of 35.6°, 60.1°, 72.1° and 75.7°. The mean tensile strength and Weibull modulus of the fiber reach 3266 MPa and 16.3, respectively. Furthermore, fracture mechanism of the fiber is discussed.

Qualitative and quantitative analyses were carried out to investigate the effect of the deposition temperature, pressure and flow rate of chemical vapor deposition imposed on the concentrations of MTS/H₂ CVD SiC gaseous species through GC/MS method. Decomposition procedures of MTS in H₂ based on the reaction rate and concentrations of species were analyzed. The results show that: (1) the identified gaseous species are CH4、C₂H₆、C₂H₄, C₃H₆, C₂H₂, MTS, SiCl₄ and CH₃SiHCl₂, of which the concentrations of CH₄ and SiCl₄ are comparatively higher; (2) temperature, pressure and flow rate have great effect on the concentrations of gaseous species, and their regular patterns follow the same dependence as the thermodynamics; (3) MTS mainly starts with the cracking and decomposition of Si-C, and experiences three stages, the reaction with H₂, the formation of middle objects and also by-products. It is suggested that the main formation route of alkane is CH₃®C₂H₆®C₂H₄®C₂H₂.

Al₂O₃ nanowires were prepared with the method of electrochemical oxidation followed by acid corrosion. The morphology and structure of Al₂O₃ nanowires were characterized by SEM, EDS and IR. The experimental results show that Al₂O₃ nanowires with hexagonal arrangement and large aspect ratio are formed from Al₂O₃ porous film by electro-oxidation of aluminum substrate. The diameter of the pure Al₂O₃ nanowires is from 16nm to 60nm, and decreases with the rising of electrolyte temperature, cell voltage and the prolonging of corrosion time. On the basis of characterization of nanowires on Al₂O₃ porous film, a possible formation mechanism was proposed.

Chemical vapor deposition (CVD) method was utilized to synthesize single-crystal AlB₁₂ nanorods on Si substrates in the high temperature horizontal furnace under H₂ and Ar atmosphere, using Al powders and BCl₃ gas as precursors without any catalysts. The morphology, crystal structures and components of the AlB₁₂ were examined by scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), selected-area electron diffraction(SAED) and energy disperse spectrometer (EDS). SEM shows that the as-synthesized nanowires with the diameter ranging from 100nm to 350 nm and length ranging from several nanometers to several micrometers. HRTEM, SAED, and EDS reveal that the AlB₁₂ nanorods are crystals elongated along the [020] direction. And growth mechanism based on the self-catalyst process is proposed for the formation of the AlB₁₂ nanorods.

The nanosized ZrO₂-8wt%Y₂O₃ (YSZ) and CeO₂/ZrO₂-8wt%Y₂O₃(CYZ) particles were agglomerated as powder feedstocks. Thermal barrier coatings were prepared on the GH30 high temperature alloy surface by atmospheric plasma spray. The microstructures of the agglomerated powders doped with 25wt% CeO₂ particles and the coating were characterized using scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD) technology. The thermal shocks resistance of the ZrO₂-8wt%Y₂O₃ (YSZ) and CeO₂/ZrO₂-8wt%Y₂O₃ (CYZ) coatings were tested at 900℃,1100℃ and 1300℃. The oxidation resistance testing of coatings were tested at 1050℃ for 100h. The results show that the nano-powder by agglomerated treatment is porous spherical. The phase compositons of the nano-CYZ coating are relatively stable t phase (t-ZrO₂, t-Zr_0.82Y_0.18O_1.91, t-Zr_0.82Ce_0.18O₂) and c phase (c-CeO₂). The average grain size of the CYZ coating is about 45nm. The nanostructured CeO₂/ZrO₂-Y₂O₃ coating exhibit higher thermal-shock and oxidation resistances than those of the nano-YSZ coating.

Zr(OH)₄ particle can be formed and negatively charged in alkaline solution with K₂ZrF₆ addition. Based on this mechanism, Zr-containing ceramic coatings were fabricated on LY12 aluminum alloy by microarc oxidation (MAO) using K₂ZrF₆ as a special additive in Na₂SiO₃-KOH base electrolyte. The modulation effects of K₂ZrF₆ addition on micro-microstructure, element distribution and phase composition were analyzed by SEM, EDS and XRD, respectively. Heat resistance of MAO coatings formed on LY12 aluminum alloy in different electrolyte was investigated. The results show that the K₂ZrF₆ addition can increase the micro-arc oxidation rate and significantly alter the structure of MAO coatings. Both the top surface and inner surface of MAO coatings fabricated in Zr-containing electrolyte become relatively smooth. Compared with the coating formed in Zr-free electrolyte, a large amount of Zr element is found in the coating formed in electrolyte with K₂ZrF₆ addition. Two main phases, γ-Al₂O₃ and α-Al₂O₃, are contained in Zr-free coating. In contrast, more amorphous phase is found in Zr-containing coating with reduced amount of crystalline alumina. Experimental results also demonstrate that Zr-containing coating exhibits higher heat resistance.

SrCo_0.4Fe_0.4Zr_0.2O_3-d (SCFZ) mixed conducting hollow fibre membranes were prepared by a dry-wet spinning technology based on the phase separation theory combined with subsequent sintering process. XRD, SEM, thermal expansion technique and oxygen permeation test were utilized to characterize the crystal phase structures, microstructures, sintering behavior and oxygen permeation flux of SCFZ powder and/or hollow fibre membranes. XRD patterns show that the crystal phase of SCFZ hollow fibre membranes are composed of perovskite main phase, SrZrO₃ and Co₃O₄ impurity phases. The content of SrZrO₃ increases with increasing the sintering temperature. The SEM images demonstrate that fingerlike pores exist adjacent to the inner and outer skin layer of membrane wall. Meantime, sponge-like pores appear in the middle zone of wall. This kind of morphology is caused by the immersion phase separation process. From the gastight, mechanical strength, sintering behavior, XRD and SEM results, the optimum sintering temperature of the green membranes is considered to be 1240℃. The SCFZ hollow fibre membranes are obtained under the optimum sintering schedule. The sintered SCFZ membranes exhibit high mechanical strength and the fracture strength reaches 74.19MPa. At 850℃, the oxygen permeation flux of the membrane is 2.9´10^-7mol/(cm² · s) under air/He gradient, and the flux is stable during the test for more than 160h.

ZnO-modified Fe_1.5P powders were synthesized successfully via a rheological phase method. X-ray diffractometry (XRD) was utilized to analyze the composition. TEM was used to characterize the morphology. The effects of ZnO modification on the electrochemical performance of the Fe_1.5P were investigated using constant current charge/discharge method, cyclic voltammogram, and electrochemical impedance spectrograph (EIS). The experimental results show that ZnO modification can enhance the rate performance of Fe_1.5P. The first discharge capacity of the ZnO-modified Fe_1.5P is 837.5mAh/g, and 69.7% higher than that of the pristine Fe_1.5P. After 215 cycles, the discharge capacity of the Fe_1.5P at 12C rate is increased to 144.3%. Furthermore, ZnO modification improve 330% of the recovery discharge capability of the Fe_1.5P at 0.1C rate. In addition, in comparison with the pristine Fe_1.5P, ZnO modification reduce 87.9% of the SEIingd  SEI film resistance R_SEI, 87% of the charge transfer resistance R_d, and 13.2% of the Warburg impedance W_b from the diffusion of lithium ions, while can improve 86.6% of the diffusion efficiency of lithium ions.

Using the methods of coated and thermal decomposed ruthenium chloride, the RuO₂ thin film was synthesized on the inner-wall surface of tantalum shell. Its morphology and structure were characterized by scanning electron microscope and X-ray diffraction. The electrochemical performances of the RuO₂ thin film electrode were tested by cyclic voltammetry, galvanostatic charging/discharging and electrochemical impedance spectroscope. The results show that the RuO₂ thin film calcinated at 280℃ has amorphous structure and the specific capacitance of the electrode is 212F/g (in 0.5 mol/L H2SO4 electrolyte) with good electrochemical performance. When the films are assembled into ST3 type 60 V 330 μF tantalum capacitors, the capacitance can still maintain 345μF after celaring and electrical aging. The equivalent series resistance (ESR) is less than 1Ω and the leakage current is less than10μA.

Alien atom doping has been adopted to modify the electrochemical performance of olivine type LiFePO₄ for cathode material. Here, we report that zinc-doping can improve the performance of LiFePO₄/C immensely by a simple method. LiFePO₄/C and Zn-doped LiFePO₄/C cathode materials were firstly synthesized by carbothermal reduction method. Physical-chemical characterizations were done by X-ray diffraction, scanning electron microscope and transmittance electron microscope. Electrochemical behavior of the cathode materials were analyzed by using cyclic voltammetry, and galvanostatic measurements were employed to characterize the reaction of lithium ion insertion and de-insertion. ICP and XRD analyses indicate that Zn ions were sufficiently doped in LiFePO₄ and did not alter its crystal structure. During de-intercalation and intercalation process of lithium ions, the doped zinc atoms protect the LiFePO₄ crystal from shrink. Consequently, the conductivity is enhanced after doping. It is noted that zinc ions doping can improve performance of LiFePO₄, especially on the aspect of stable cycle-life at higher C rate.

Laser-induced breakdown spectroscopy (LIBS) has been applied to determine the oxygen concentration in heavily doped silicon wafer by using a high power pulsed laser and an optical fibre coupled CCD spctrometer. The relative concentration of oxygen in the heavily doped silicon wafer was calculated by the ratio of the integral intensity of the O_I emission of oxygen to the SiI emission silicon from the LIBS spectra. A calibration curve was obtained by comparing the oxygen concentration determined by LIBS with the oxygen concentration determined by conventional FTIR technique used in Si industies, in which a set of four lightly doped CZ silicon wafers were used. Based on the calibration curve, quantitative oxygen concentration in several heavily doped silicon samples was measured.