Yttria-stabilized zirconia and α-alumina films were prepared by laser chemical vapor deposition at deposition rates of several hundred micrometers per hour. Moreover, the structural oxide coatings by laser chemical vapor deposition are reviewed. The laser can significantly accelerate the chemical reaction and grain growth in CVD, yielding high deposition rates. The films contain large amounts of nanopores that act as thermal insulation and are thus promising as coating materials for gas turbine blades of Ni-based superalloys and WC-Co cutting tools.

Sodium beta alumina (Na-β-alumina) films were synthesized by heat treatment of NaAl₆O_9.5 and γ-NaAlO₂ films at temperatures of 1 373-1 573 K. Single-phase γ-NaAlO₂ and NaAl₆O_9.5 films were prepared by laser chemical vapor deposition at the deposition temperatures of 976 and 1 100 K, respectively. Subsequent heat treatment of the films resulted in the formation of Na-β-alumina with α-Al₂O₃ at temperatures above 1 373 K for NaAl₆O_9.5 and 1 473 K for γ-NaAlO₂. On heat treatment at temperatures of 1 473-1 573 K, the faceted morphology with terraces of the as-deposited (110)-oriented γ-NaAlO₂ films transformed to a porous morphology with platelet grains comprising Na-β-alumina and α-Al₂O₃. On heat treatment at temperatures of 1 373-1 473 K, the pyramidal, faceted grains of as-deposited NaAl₆O_9.5 films transformed to planer, shapeanisotropic morphology in the film of mixed Na-β-alumina and α-Al₂O₃. A dense morphology was observed in both the as-deposited and heat-treated NaAl₆O_9.5 films.

Electrospray, as a liquid source supply system, has been applied to chemical vapour deposition (CVD). In thermal CVD, the microstructure of the obtained films changes from dense to coarse granular because of the decreasing surface temperature during deposition. Using the electrospray laser chemical vapour deposition method, we prepared homogenous alumina coatings. We found that laser irradiation was effective in compensating the surface temperature decrease, and an alpha-alumina coating with dense columnar microstructures was obtained at a deposition rate of 200 μm/h using 200 W Nd:YAG laser irradiation.

c-axis-oriented SmBa₂Cu₃O₇ (SmBCO) films have been deposited on (100)- LaAlO₃ (LAO) substrate by metal organic chemical vapor deposition (MOCVD) technique. The effects of deposition temperature (T _dep) and total pressure (P _tot) on the orientation and microstructure of SmBCO films were investigated. The orientation of SmBCO films transformed from a-axis to c-axis with increasing of T _dep from 900 to 1 100 °C. At T _dep = 1 050 °C, SmBCO films had c-axis orientation and tetragon surface. At P _tot= 400-800 Pa and T _dep = 1 050 °C, totally c-axis-oriented SmBCO films were obtained. The R _dep of SmBCO films increased firstly and then decreased with increasing P _tot. The surface of SmBCO films exhibited tetragon morphology at 1 050 °C and 400 Pa. Maximum thickness of SmBCO film deposited was 1.2 μm at P _tot = 600 Pa, and the corresponding R _dep was 7.2 μm·h^-1.

Antimony doped tin oxide (ATO) thin films have been prepared by pulsed laser deposition (PLD) method. The intrinsic effect of Sb dopant, including the Sb content, transition degree between Sb³⁺ and Sb⁵⁺ and crystallinity on the electrical and optical properties of the ATO thin films is mainly investigated. It is suggested that the transition degree of Sb³⁺ towards Sb⁵⁺ (Sb⁵⁺/Sb³⁺ ratio) is determined by Sb content. When the Sb content is increased to 12 at%, the Sb⁵⁺/Sb³⁺ ratio reaches the highest value of 2.05, corresponding to the resistivity of 2.70×10^-3 Ω·cm. Meanwhile, the Burstein-Moss effect caused by the increase of carrier concentration is observed and the band gap of the ATO thin films is broadened to 4.0 eV when the Sb content is increased to 12 at%, corresponding to the highest average optical transmittance of 92%. Comprehensively considering the combination of electrical and optical properties, the ATO thin films deposited with Sb content of 12 at% exhibit the best properties with the highest “figure of merit” of 3.85×10^-3 Ω-1. Finally, an antimony selenide (Sb₂Se₃) heterojunction solar cell prototype with the ATO thin film as the anode has been prepared, and a power conversion efficiency of 0.83% has been achieved.

Al-doped ZnO (AZO) thin films were grown on c-sapphire substrates by laser ablation under different oxygen partial pressures (P _O2). The effect of PO2 on the crystal structure, preferred orientation as well as the electrical and optical properties of the films was investigated. The structure characterizations indicated that the as-grown films were single-phased with a wurtzite ZnO structure, showing a significant c-axis orientation. The films were well crystallized and exhibited better crystallinity and denser texture when deposited at higher P _O2. At the optimum oxygen partial pressures of 10 - 15 Pa, the AZO thin films were epitaxially grown on c-sapphire substrates with the (0001) plane parallel to the substrate surface, i e, the epitaxial relationship was AZO (000 1) // Al₂O₃ (000 1). With increasing P _O2, the value of Hall carrier mobility was increased remarkably while that of carrier concentration was decreased slightly, which led to an enhancement in electrical conductivity of the AZO thin films. All the films were highly transparent with an optical transmittance higher than 85 %.

The Cu _xSi_1-x thin films have been grown by pulsed laser deposition (PLD) with in situ annealing on Si (001) and Si (111), respectively. The transformation of phase was detected by X-ray diffraction (XRD). The results showed that the as-deposited films were composed of Cu on both Si (001) and Si (111). The annealed thin films consisted of Cu + η”-Cu₃Si on Si (001) while Cu + η’-Cu₃Si on Si (111), respectively, at annealed temperature (T _a) = 300-600 °C. With the further increasing of T _a, at T _a= 700 °C, there was only one main phase, η”-Cu₃Si on Si (001) while η’-Cu₃Si on Si (111), respectively. The annealed thin films transformed from continuous dense structure to scattered-grain morphology with increasing T _a detected by field emission scanning electron microscope (FESEM). It was also showed that the grain size would enlarge with increasing annealing time (t _a).

High temperature oxidation behavior of the bond coat layer is a critical factor that controls the failure mechanism of thermal barrier coatings (TBCs). Previous work reveald that TBCs with cryomilled NiCrAlY bond coats exhibited an improved oxidation behavior compared to equivalent TBCs with conventional bond coats. The cryomilled NiCrAlY bond coats contributed to a slower growth rate of thermally grown oxides (TGO) with a final thinner thickness and enhanced homogeneity in TGO composition. To better understand the improved oxidation behavior, a mechanistic investigation based on diffusion theory and quantum mechanics is performed to elucidate the role of aluminum diffusion in the oxidation behavior and how the microstructural features of the cryomilled NiCrAlY bond coats, i e, the creation of a thermally stable, uniform distribution of ultrafine Al-rich oxide dispersoids, affect the diffusion kinetics of Al and the migration of free electrons. It is revealed that these Al-rich oxide dispersoids result in a uniform diffusion of Al and slow migration of free electrons within the NiCrAlY bond coat, consequently leading to the improved oxidation behavior.

The effect of substrate temperature on the structure and magnetic properties of CoPt/AlN multilayer films has been investigated. The crystallinity of CoPt has been improved with increasing substrate temperature from room temperature to 400 °C. After post-annealing process, L1₀ CoPt structure transformation has also been promoted. However, since the easy magnetic axis of L1₀ CoPt is in [001] orientation, the promotion of L1₀ CoPt transformation causes the change of easy magnetic axis in (111) textured CoPt layers, which impairs the perpendicular magnetic anisotropy. The optimum substrate temperature should be room temperature to obtain the strongest perpendicular magnetic anisotropy according to the results of the present work.

Tin oxide (SnO₂) and fluorine doped tin oxide (FTO) films were prepared on glass substrates by sol-gel spin-coating using SnCl₄ and NH₄F precursors. Fluorine doping concentration was fixed at 4 at% and 20 at% by controlling precursor sol composition. Films exhibited the tetragonal rutile-type crystal structure regardless of fluorine concentration. Uniform and highly transparent FTO films, with more than 85% of optical transmittance, were obtained by annealing at 600 °C. Florine doping of films was verified by analyzing the valence band region obtained by XPS. It was found that the fluorine doping affects the shape of valence band of SnO₂ films. In addition, it was observed that the band gap of SnO₂ is reduced as well as the Fermi level is upward shifted by the effect of fluorine doping.

The optimized growth conditions for high density germanium (Ge) nanowires and P-doped Ge nanowires on Si (111) substrate were investigated, the phosphorus (P)-doping in Ge nanowires was also characterized. Vapor liquid solid-low pressure chemical vapor deposition (VLS-LPCVD) of Ge nanowires was conducted with different thicknesses of Au film as catalyst, different flow rates of GeH₄ as precursor and PH₃/Ar as co-flow. The morphologies of the Ge nanowires were characterized by scanning electron microscopy (SEM), the P-doping was verified by micro Raman spectroscopy via measuring the P local vibrational peak (342-345 cm^-1) and asymmetric broadening of Ge-Ge vibrational peak (about 300 cm^-1), respectively. The characterization results show that 1 nm thickness of Au catalyst is the most suitable condition among thicknesses of 0.1, 1, 5, and 10 nm for the growth of high density Ge nanowires at 300 and 350 °C, and 0.5 sccm is the best flow rate of PH₃/Ar to grow high density and large scale P-doped Ge nanowires among flow rates of 0.5, 1 and 2 sccm. The P impurity can be doped into Ge nanowires effectively during LPCVD process at 350 °C.

Forming adsorbents FFA-R, FFA-A and FFA-B were prepared from different particle size coal fly ashes FA-R, FA-A and FA-B, their average particle sizes (d ₅₀) were 15.75, 3.61 and 1.73 μm respectively. The structure and adsorption properties for Cr⁶⁺ of forming adsorbents from aqueous solution were studied. The results show that forming adsorbent prepared from the coal fly ash with smaller particle size exhibits higher specific surface area, higher pore volume and better adsorption properties for Cr⁶⁺.The adsorption kinetics of Cr⁶⁺ on FFA-R, FFA-A and FFA-B fitts the second order kinetic model and the second adsorption rate constants are 7.523, 3.197 and 2.187 mg·g^-1· min^-1/2, respectively. The adsorption of Cr⁶⁺ on FFA-R, FFA-A and FFA-B can be described in terms of Langmuir isotherms better, and the adsorption processes are spontaneous and exothermic.

Hydrogen is a promising fuel for it is clean, highly abundant and non-toxic, but on-board storage of hydrogen is still a challenge. So it is imperative to have an efficient method of hydrogen storage. The mesoporous MCM-48 especially the nickel-containing MCM-48 has great potential in hydrogen storage. MCM- 48 was prepared by hydrothermal synthesis. Then electroless plating technology was used to deposit Ni on the surface of MCM-48 under ultrasonic environment. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and N₂ adsorption-desorption were employed to investigate the pore structure properties. The results showed that all the samples had Ia3d cubic structure and pore channels were highly ordered. Hydrogen adsorption studies showed that the MCM-48 after nickel plating adsorbed nearly twice the amount of hydrogen than pure MCM-48 at 2.0 MPa, 263 K. So we believe that a small amount of Ni can improve the capacity of hydrogen adsorption of MCM-48 efficiently.

Nanocrystalline zirconia (ZrO₂) was synthesized using a microwave-hydrothermal process. The effect of pH on the crystallization of the ZrO₂ powders was investigated. The phase and microstructure of ZrO₂ powders were examined using X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). Results show that pure m-ZrO₂ can be obtained at low pH (pH<2). Pure t-ZrO₂ is formed at pH = 7 and 14. The size of the ZrO₂ crystals is in the range of 8-26 nm and decreases with increasing pH. The formation of m-ZrO₂ results from the precipitation of ZrO₂ from solution. The t-ZrO₂ is formed through the in-situ structural rearrangement of amorphous Zr(OH) _xO _y. The stabilization of t-ZrO₂ is attributed to the small crystal size and the adsorption of hydroxy ions on the surfaces of the crystals.

The structural and elastic properties of the recently-discovered wII- and δ-Si₃N₄ are investigated through the plane-wave pseudo-potential method within ultrasoft pseudopotentials. The elastic constants show that wII- and δ-Si₃N₄ are mechanically stable in the pressure ranges of 0-50 GPa and 40-50 GPa, respectively. The α→wII phase transition can be observed at 18.6 GPa and 300 K. The β→δ phase transformation occurs at pressures of 29.6, 32.1, 35.9, 39.6, 41.8, and 44.1 GPa when the temperatures are 100, 200, 300, 400, 500, and 600 K, respectively. The results show that the interactions among the N-2s, Si-3s, 3p bands (lower valence band) and the Si-3p, N-2p bands (upper valence band) play an important role in the stabilities of the wII and δ phases. Moreover, several thermodynamic parameters (thermal expansion, free energy, bulk modulus and heat capacity) of δ-Si₃N₄ are also obtained. Some interesting features are found in these properties. δ-Si₃N₄ is predicted to be a negative thermal expansion material. The adiabatic bulk modulus decreases with applied pressure, but a majority of materials show the opposite trend. Further experimental investigations with higher precisions may be required to determine the fundamental properties of wII- and δ-Si₃N₄.

An ambient pressure synthesis of SiO₂/TiO₂ binary aerogel was prepared through the low-cost precursors of titanium tetrachloride (TiCl₄) and sodium silicate (Na₂O·nSiO₂). After gelation, solvent exchange and surface modification were performed simultaneously and the modified gel was finally dried under ambient pressure. Microstructural analyses by transmission electron microscope (TEM) indicate that fabricated SiO₂/TiO₂ aerogel composite shows similar sponge-like nanostructure as silica aerogel, and the Brunauer–Emmett–Teller (BET) analysis shows that the specific surface area of the composite reaches 605 m²/g, and the average pore size is 9.7 nm. Such binary aerogel exhibits significant photocatalytic performance in this paper for treating model pollutant of methyl orange (MO), and the decolorizing efficiency of MO is detected as 84.9% after 210 mins exposure to UV light irradiation. Degraded gel suspends in the water so as to separate from solution for reuse, and after 4 times recycling, 70% degradation efficiency can be easily reached when composite catalyzed system is exposed for 210 mins under UV irradiation.

We established a model for investigating polycrystalline silicon (poly-Si) thin film transistors (TFTs). The effect of grain boundaries (GBs) on the transfer characteristics of TFT was analyzed by considering the number and the width of grain boundaries in the channel region, and the dominant transport mechanism of carrier across grain boundaries was subsequently determined. It is shown that the thermionic emission (TE) is dominant in the subthreshold operating region of TFT regardless of the number and the width of grain boundary. To a poly-Si TFT model with a 1 nm-width grain boundary, in the linear region, thermionic emission is similar to that of tunneling (TU), however, with increasing grain boundary width and number, tunneling becomes dominant.

Wafer curvature method has been applied to determine the internal stress in the films using Stoney’s equation. During the film deposition, the wafer fixation on the sample holder will restrict the deformation of the rectangle-shaped wafer, which may result in the stress datum difference along length and width direction. In this paper, the effect of wafer size and the wafer fixation on the TiN film internal stress measured by wafer curvature method was discussed. The rectangle-shaped wafers with different length/width ratios (L/W=1:1, 2:1, 3:1 and 4:1) were fixed as a cantilever beam. After the TiN films deposition, the profiles of the film/wafer were measured using a stylus profilometer and then the internal stress was calculated using the Stoney equation in the film. The results showed that the fixed end of the wafers limited to some degree the curvature of the wafers along the width direction. For film internal stress measured by wafer curvature method, the wafer profile should be scanned along the length direction and the scan distance should be greater than or equal to half of wafer length. When the length/width ratio of the wafer reached 3:1, the wafer curvature and the calculated stress were basically the same at different positions along the length direction. For film internal stress measured by wafer curvature method, it was recommended that the length/width ratio of wafer should be considered to be greater than or equal to 3:1, and the deformed profile was scanned along the length direction.

The Kubelka-Munk revised theory was adopted to derive the mix design theory of high solar reflectance and high emissivity coatings. When the concentration of each colorant is within 20%, and the width of the coating is more than 200 μm, each colorant has enough covering power in visible and near-infrared spectral range. It can be assumed that the addition of colorants in coatings can only change the solar spectral absorption ratio rather than solar spectral scattering coefficient. The spectral scattering coefficient of coatings tends to a constant. The spectral absorption-scattering property of each colorant can be characterized through one parameter. The spectral absorption-scattering coefficient of coatings can be calculated with the multivariate linear relationship of each pigment. Moreover, the results can be expanded for high solar reflectivity and high long-wave emissivity coating preparation. The accuracy of Kubelka-Munk revised theory has been tested and verified through comparison between the calculated value and tested value of coating reflectance.

Fibrous brucite, a kind of brucite with unique structure and physical properties, was modified with stearic acid as a surface modifier. In order to investigate the mechanism of surface modification, the fixation of stearic acid on fibrous brucite and the induced changes in surface properties were studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR), Raman spectroscopy and thermo-gravimetric analysis (TGA). XRD analysis indicates that the modification of fibrous brucite with stearic acid does not cause any changes in the structure of fibrous brucite mineral. Spectroscopy and thermal analysis show that the surfactant molecules are not only directly adsorbed on the surface of the mineral, but also chemisorbed on mineral surface by forming chemical bonds between the modifier and magnesium hydroxide.

Ordered mesoporous ceria and ceria-zirconia with high specific surface area were prepared by nanocasting of a mesoporous silica KIT-6 template and used for soot oxidation. The as-synthesized ordered mesoporous ceria and ceria-zirconia were characterized by XRD, TEM,Nitrogen adsorption-desorption,Raman spectroscopy, and XRF. The results indicate that mesoporous ceria and ceria-zirconia possess highly ordered mesoporous structure, and exhibited excellent catalytic performance in soot oxidation. T ₅₀ of mesoporous ceria and ceria-zirconia are 475 and 470 °C, respectively.The high catalytic activity of mesoporous materials can be attributed to the mesoporous structure and small crystallite size. Moreover, aged mesoporous materials exhibit high catalytic activity.

To investigate the ballistic performance and damage characteristics of quasi threedimensional (3D) needle-punched Cf/SiC composites prepared by chemical vapor infiltration (CVI), penetration experiments were conducted by using 7.62 mm armor piercing incendiary (API). Macro and micro fracture morphologies were then observed on recycled targets. The results show that the protection coefficient of 3D Cf/SiC composites is 2.54. High porosity and many micro thermal stress cracks may directly lead to the lower ballistic performance. Flat fracture morphology was observed on the crater surface. The low dynamic fracture strength along layer direction may be attributed to the voids and microcracks caused by residual thermal stress. The damage characteristics of Cf/SiC composites include matrix cracking, fiber bundle cracking, interfacial debonding, fiber fracture, and fiber bundle pull-out. And interfacial debonding and fiber fracture may play major roles in energy absorption.

A new multiscale numerical approach was presented to predict the ionic diffusivity of cement based materials, which incorporated the lattice Boltzmann method, the conjugate gradient method, and the random walk method. In particular, the lattice Boltzmann method was applied to model the ionic diffusion in pore space of cement paste, while the upscaling of effective ionic diffusivity from cement paste (mortar) to concrete was processed by means of the conjugate gradient method and the random walk method. A case study was then presented, i e, the chloride diffusivity of concrete affected by sand content and gravel content. It is shown that the results of numerical prediction agree well with those of experimental measurements adopted from literatures. The multiscale numerical approach provides a prior assessment of ionic diffusivity for cement based materials from a microstructural basis.

Welan gum has been widely used in oil cement and grouting materials for its excellent rheological properties and anti-bleeding, and most of all, being friendly to the environment. However, when welan gum was added, the fluidity of mortar decreased sharply, so it should be used together with a superplasticizer to enable good workability. With its powerful charge density in the molecular structure, the competitive adsorption between welan gum and other admixtures happened remarkably during the addition process. Consequently, we experimentally studied on the bleeding rate and rheological properties of cement slurry, fluidity and mechanical properties of mortar with welan gum mixed with superplasticizer, aiming at understanding the competitive adsorption phenomenon by application of welan gum mixed with superplasticizer. By measuring the hydration heat and zeta potential, the mechanism of interaction of welan gum with superplasticizer was deduced and explained. The results showed that it could ensure a good dispersion effect when welan gum is mixed with the two kinds of superplasticizer. Welan gum had little impact on the naphthalene superplasticizer, but did have a substantial influence on polycarboxylate. In practice, adding welan gum after PCE acted with cement for 2 min could effectively avoid the competitive adsorption and then achieve better performance. On this viewpoint for mortar with PCE, new delay release welan gum needs further research and development.

Effect of isobutyl-triethoxy-silane penetrative protective agent on the carbonation resistance of the concrete was studied. The concrete specimens for the 28 d accelerated carbonation process were manufactured with w/c of 0.49 and 0.64, both in the presence and absence of silane and mineral admixture. The penetration of isobutyl-triethoxy-silane and the carbonation of concrete were investigated by penetration depth, carbonation depth, XRD, SEM, and pore size distribution. The results showed that concrete compactness played an important role in the silane penetration and carbonation resistance. Penetration depth of silane-treated concrete mainly depended on the compactness of the concrete, and could not remarkably change through the accelerated carbonation process. In the accelerated carbonation process, penetrative protective agent improved the carbonation resistance of the higher compactness concretes but accelerated the carbonization process of the lower compactness concretes. As penetrative protective agent penetrated along the external connectivity pores into concrete not filling the entire surface area, the inorganic film could not fully protect the Ca(OH)₂ phase from carbonation. After 28 d accelerated carbonation, fibrous hydration products disappeared and the surface holes decreased. Due to the formation of carbonized products, the porosity of the concrete surface decreased, especially in high-strength concrete.

In order to investigate the effects of carbonation on the microstructure of cement concrete, the carbonation depth and microstructure of cement paste with 0.3, 0.4 and 0.5 water/cement ratio after 7, 14, 21 and 28 d accelerated carbonation were studied respectively. The results showed that with the increase of waterto- cement ratio and carbonation age, the carbonation depth was deepened with faster early carbonation speed and slower later carbonation rate. Carbonation densified the structure of hardened cement stone with refinement of pore structure and reduced porosity. Then, during the carbonation process from the surface to the inside of carbonation area, it was prone to form micro-cracks extending to the interior specimen, resulting in cement paste carbonation depth uneven. It is further illustrated that the color reaction method using phenolphthalein solution combined with X-CT and X-ray diffraction analysis is much more reasonable to evaluate the cement concrete carbonation degree. Moreover, during carbonation process sulfur element in cement paste migrated to the area un-carbonated and the concentrated shape of sulfur element is consistent with the coloring region in carbonation interface. Finally it was identified that carbonation not only reduced the pH value in cement concrete but also made prone to crack in carbonation zone, which increased the probability of reinforcement corrosion.

A new microcrystal muscovite composite superabsorbent was synthesized by UV photopolymerization using 2-hydroxy-2-methylpropiophenone (1 173) as photoinitiator, N, N-methylene bisacrylamide(MBA) as crosslinker, acrylic acid (AA), acrylamide (AM) and sodium 4-styrenesulfonate (SSS) as comonomers. Factors affecting water and salt absorption of the microcrystal muscovite composite superabsorbent, such as crosslinker amount, microcrystal muscovite concentration, photoinitiator content, and SSS concentration, were systematically studied. Water retention capacity of the composite superabsorbent was also investigated. The results show that microcrystal muscovite composite superabsorbent has water absorbency of 550 g/g, salt absorbency of 62 g/g, and water retention of 60% after heating at 70 °C for 40 h. The microcrystal muscovite is physically combined into the polymeric network without destroying its polycrystalline structure and the surface of the microcrystal muscovite composite superabsorbent has some deep and small holes.

The reaction kinetics between diazide(4,4’-biphenyl dibenzyl azide) and different diynes (dipropargyl bisphenol A and 1,3-diethynylbenzene) were studied by means of differential scanning calorimetry (DSC) and nuclear magnetic resonance spectroscopy (¹H-NMR). DSC was adopted to analyze the reactions under bulk polymerization condition, while ¹H-NMR for solution reaction polymerization was conducted. The apparent activation energies (E _α) calculated by Kissinger’s method were 77.96, 81.24 kJ/mol, which were confirmed by Friedman’s method, and 65.45, 69.36 kJ/mol by ¹H-NMR for dispropargyl bisphenol A/4,4’-biphenyl dibenzyl azide and 1,3-diethynylbenzene/4,4’-biphenyl dibenzyl azide, respectively. The polymerizations between the diazide and diynes were first-order reactions based on calculation from both DSC and ¹H-NMR. The results showed that the reaction between dipropargyl bisphenol A and 4,4’-biphenyl dibenzyl azide was easier than that between 1,3-diethynylbenzene and 4,4’-biphenyl dibenzyl azide, verifying that the reactivity of aliphatic alkyne was higher than that of aromatic alkyne.

In order to improve the thermal properties of polylactic acid (PLA) filament, nano-SiO₂ was applied to mix with PLA, then they were spun as composite filament by melt-spinning. The dispersion of nano-SiO₂ and the fracture surfaces of filaments were studied by scanning electron microscopy (SEM). The properties of composite filament, such as orientation degree, mechanical properties, and surface friction properties, were analyzed. The thermal performances of composite filament were analyzed by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). The results showed that the nano-SiO₂ modified by 5% KH-550 could disperse evenly and loosely in nano-scale, and 1 wt% and 3 wt% nano-SiO₂ dispersed throughout PLA evenly. As the quantity of nano-SiO₂ increased, the properties of composite filament, such as orientation degree, friction coefficient, thermal decomposition temperature, and glass transition temperature, increased more or less. The breaking tenacity increased when 1 wt% SiO₂ was added in PLA, but declined when 3 wt% SiO₂ was added.

The porosity of carbon fiber reinforced polymer (CFRP) workpiece is tested by ultrasonic in pulse-echo mode. When the ultrasonic frequency is close to the resonant frequency of the workpiece, the resonance will occur along the thickness direction. If the CFRP workpiece contains voids, the resonant frequency will decrease. The result of ultrasonic testing experiment clearly draws the conclusion that the center frequency of the backscattered signal spectrum declines with increasing porosity. Based on the above theory and conclusion, the three-dimensional (3D) voids identification and location method is established. Firstly, the ultrasonic signals are collected and the center frequencies of the backscattered signal spectra are calculated. Then the C-scan of center frequency is generated to identify the voids. At last the B-scan of center frequency for the region containing voids is generated to determine the depth of the voids. The experimental results show that, by using this method, the voids in the CFRP workpiece can be identified and pinpointed.

Three different online heat treatment processes were designed to study the effects on the mechanical properties of a 0.19C-1.6Si-1.6Mn (wt%) hot rolled strip steel. The microstructures were characterized by means of SEM, TEM, EPMA, and XRD. The mechanical properties were estimated by tensile tests. Results showed that a satisfying combination of strength and ductility could be obtained through the ferrite relaxation and direct quenching and partitioning process. Analysis was also focused on this process. The microstructure contained proeutectoid ferrite grains, martensite packets and blocky or interlath retained austenite, and also contained carbide-free bainite in the case of relatively high quench temperatures. The retained austenite fraction was increased through proeutectoid ferrite and partial bainite transformation, while the tensile strength was also consequently decreased. The most of retained austenite transformed to ferrite under deformation and the elongation was obviously improved.

Glass-forming ability (GFA) and mechanical properties of (Zr_0.58Nb_0.03Cu_0.16Ni_0.13Al_0.10)_100-xLu _x (x = 0-3 at%) alloys have been investigated. The GFA of Zr₅₈Nb₃Cu₁₆Ni₁₃Al₁₀ alloy is dramatically enhanced by adding Lu. The (Zr_0.58Nb_0.03Cu_0.16Ni_0.13Al_0.10)₉₈Lu₂ alloy possesses the highest GFA in the studied Zr-Nb-Cu-Ni-Al-Lu alloys, with its critical diameter for glass formation reaching 20 mm by copper-mould casting method, while that of the Lu-free Zr₅₈Nb₃Cu₁₆Ni₁₃Al₁₀ alloy is 7 mm. The critical diameters of (Zr_0.58Nb_0.03Cu_0.16Ni_0.13Al_0.10)100-xLux (x = 1 at% and 3 at%) alloys are 15 mm and 12 mm, respectively. The Lu addition to Zr₅₈Nb₃Cu₁₆Ni₁₃Al₁₀ alloy induces the change of initial crystallization phases from face-centred-cubic Zr₂Ni and tetragonal Zr₂Ni phases for the Lu-free Zr₅₈Nb₃Cu₁₆Ni₁₃Al₁₀ alloy to an icosahedral quasi-crystalline phase for the Lu-doped alloys, which may be the origin for the enhanced GFA of the Lu-doped alloys. The compressive fracture strength and plastic strain of the bulk glassy (Zr_0.58Nb_0.03Cu_0.16Ni_0.13Al_0.10)₉₈Lu₂ alloy are 1 610 MPa and 1.5%, respectively.

The non-isothermal and isothermal crystallization kinetics of Zr_72.5Al₁₀Fe_17.5 glassy alloy was investigated using differential scanning calorimeter (DSC). Under non-isothermal heating condition, the primary phase in the initial crystallization is Zr₆Al₂Fe phase and the final crystallized products consist of Zr₆Al₂Fe, Zr₂Fe and a-Zr phases. The apparent activation energy for crystallization estimated using the Kissinger method is 342.1 ± 8.1 kJ/mol. The local activation energy decreased with the increase in the crystallization volume fraction during nonisothermal crystallization. Under isothermal heating condition, the average Avrami exponent of about 2.76 implies a mainly diffusion-controlled three-dimensional growth with an increasing nucleation rate. The local activation energy for isothermal crystallization shows a different variation trend from that for nonisothermal crystallization, indicating different nucleation-and-growth mechanisms for the two crystallizaiton conditions.

Centrifugal casting was applied to produce cylindrical castings using SiCp/Al composite slurry, which contained 20% SiC particles. The castings comprised a particle free zone and a particle rich zone. The amount of SiC particles had a dramatic transformation from the particle rich zone to the particle free zone, and the maximum content of SiC particles in the particle rich zone reached up to 40 vol%. The ultimate tensile strength (UTS) of the as-cast SiCp / Al composites in the particle rich zone was 143 MPa, and the fracture was caused by the desorption of SiC particles from matrix alloy. The coefficient of thermal expansion (CTE) of the SiC_p / Al composites in the range of 20 and 100 °C was determined as 16.67×10^-6 s^-1, and the experimental CTE was lower than the predicted data based on the Kerner’s model. The results show that the decrease in CTE in the case of the composites at high temperature stage can be attributed to the solute concentration of Si in Al and the plastic deformation of the matrix alloy in the composites with void architecture.

Galvanic corrosion on samples of AZ91D magnesium alloy coupled with 2A12 aluminum alloy during neutral salt spray test was investigated. The variations of the surface potential were measured using scanning kelvin probe (SKP). The results showed that galvanic effect on the corrosion of AZ91D magnesium alloy is closely related to the potential difference between the anodic and cathodic materials. In the initial period, corrosion only occurred in a narrow area at the coupling interface because of the limited distance galvanic current. Then, the corrosion rate of 2A12 aluminum alloy was accelerated due to its poor stability in strong alkali environment, which was attributed to the strong alkalization caused by the corrosion of AZ91D magnesium alloy. With the increase of the potential of 2A12 aluminum alloy as a result of the continuous covering of corrosion products, the potential difference between the two materials was enlarged, which enhanced the galvanic corrosion.

A polymer blends containing thermoplastic polyurethane (TPU) and poly (lactic acid) (PLA) as a biomedical material were prepared by a process of modifying thermally induced phase separation (MTIPS) and melt blending. The influences of composition, shear frequency, and temperature on the rheological behaviors of the blends were investigated by small amplitude oscillatory shear rheology. The results revealed that the addition of TPU into PLA significantly decreased the non-Newtonian index of the blends, and increased the sensitivity of the blends on shear rate, suggesting that optimization of the shear rate and temperature could improve the flowability of the blend melts in the extrusion process. In addition, the results of SEM images revealed that TPU distributed well into PLA matrix and showed good compatibility between the TPU and PLA, which made the blends with good toughness. The primary cytocompatibility of the blends was evaluated using C2C12 cells. The results suggested that the TPU/PLA blends did not affect cell growth, showing no cytotoxicity. In short, the TPU/ PLA blends with excellent toughness had potential application as biomedical devices.

A series of aliphatic biodegradable poly(ether-ester)s based on poly(butylene succinate) (PBS) as hard segment and poly (tetramethylene oxide) (PTMO, M _n=1 000 g/mol) as soft segment were synthesized. The composition dependence of thermal behavior, morphology and mechanical properties was investigated by differential scanning calorimetry (DSC), atomic force microscopy (AFM), and tensile testing. The crystallization temperature (T _c) and melting temperature (T _m) of the PBS block within poly(ether-ester)s decrease steadily at first, but decrease sharply with PTMO content above 50 wt%. Two crystallization peaks were detected for PTMO in PBSPTMO60 sample, suggesting the occurrence of fractionated crystallization. The crystallization enthalpies (ΔH _c) and melting enthalpies (ΔH _m) of PBS block decrease at first, then increase as PTMO content increases further. AFM has demonstrated that phase-separated morphology transforms from a phase of continuous hard matrix to one of continuous soft matrix containing isolated hard domain as PTMO content is increased. Finally, the results of tensile testing show that the poly (ether-ester)s present the behavior of plastics when PTMO content is below 40 wt%, and of thermoplastic elastomers with PTMO content above 50 wt%. By varying the composition of copolymer, the aliphatic poly (ether-ester)s plastics, or especially biodegradable aliphatic poly(ether-ester)s thermoplastic elastomers can be obtained.

Phosphate-mineralization microbe was chosen to study the influences of bacterial mixture, filtrate, bacteria solution, bacterial body and bacterial secretion on barium hydrogen phosphate crystal formation. The chemical compositions and structures of samples were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction techniques (XRD), revealing that the crystal morphology of barium hydrogen phosphate was dumbbell-shaped pattern, nanoparticles via aggregate clusters, irregular sphere with different sizes. The results indicated that bacterial body and bacterial secretion could induce the formation of irregular quadrilateral and spheres, respectively. But the effect of bacterial secretion was stronger than that of bacterial body when induced barium hydrogen phosphate crystal in bacteria solution. However, the crystals form could be affected only in bacterial mixture, but filtrate could induce the formation of nanoparticles. As a result, the bacteria and metabolites play an important role in the process of crystal nucleation, growth, and accumulation of barium hydrogen phosphate.