Mono-dispersed organic microspheres of polymethyl methacrylate (PMMA) and polystyrene (PS) were prepared via soap-free emulsion polymerization, and which then were blended with waterborne epoxy resin to prepared composite paint of organic microspheres / waterborne epoxy composite. Finally the composite coating was applied on the surface of steel sheet by air spraying method. The organic microspheres were characterized by dynamic light scattering (DLS) and scanning electron microscope (SEM). The anti-corrosion property of the composite coatings with different P/B ratio (the ratio of pigment to base material) was investigated by electrochemical impedance spectroscopy (EIS)、salt spray test and adhesion test. The results show that the coatings with P/B=0.007 has the best performance in anti-corrosion to salt spray and adhesion to the substrate. The composite coating has better corrosion resistance than that of the coating of blank waterborne epoxy resin because of that the addition of organic microspheres can enhance the denseness of the coatings.

As the key material of components used for elevated temperature gas turbines,the failure mechanism of thermal barrier coatings (TBCs) under service conditions has been the hot spot of research for a long time. The influence of strain range,pre-oxidation and dwelling time at the maximum temperature on the thermal gradient mechanical fatigue (TGMF) behavior of a superalloy with TBCs was investigated. It is demonstrated that the fatigue life decreases with the increase of strain range. With the increase of pre-oxidation and dwelling time,more oxidation damage is induced,thus resulting in shortened fatigue life. During tests,bond coat gets oxidized and forms thermally grown oxide (TGO) at the bond coat/ceramic top coat interface. Cracks are initiated in TGO and propagate along the bond coat/ceramic top coat interface,forming laminated cracks. When the laminated ion connect with the segmentation cracks in ceramic top coat,the TBCs spall. At last,a TGMF lifetime model is established by considering the influence of mechanical strain and oxidation damage.

The tribological behavior of Cr doped diamond-like carbon coating (Cr-DLC) was investigated systematically in poly-alpha-olefin (PAO) oil at 180 °C (operating temperature of engine oil) with and without antiwear additive zinc dialkyldithiophosphate (ZDDP) for various applied loads. Then the worn surface was characterized by means of Energy dispersive X-ray spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Results show that ZDDP-derived lubrication film can suppress the surface graphitization of Cr-DLC coating. In addition, the Cr-doping could increase the activity of friction surface to accelerate the tribochemical reaction between coating and ZDDP, which promoting the formation of lubrication film and the accumulation of antiwear products, therewith, improved tribological be havior of Cr-DLC coating in PAO with ZDDP additive.

Totally encapsulated microcapsules of jasmine fragrance were prepared by in situ polymerization with melamine resin as wall material and inorganic nanometer silicon dioxide as surface modifier. The morphology, chemical composition, structure and embedding rate of the prepared microcapsules were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectrometric test, thermo gravimetric analysis (TG-DTG). Results show that the totally encapsulated microcapsules of jasmine fragrance present a core-shell structure with the capsule shell of good tightness and an embedding rate of 18%.

The temper resistance,thermal stability,high temperature thermal conductivity and thermal fatigue were investigated for a new Mo-W type hot work die steel SDCM-S. The results show that in comparison with the convensional H13 steel,the SDCM-S exhibits better temper resistance and thermal stability with a hardnessabove 38HRC after holding at 620℃ for 20 h,which higher than H13 by 8HRC,wihle its second hardening temperature appeared at 580℃ which higher than H13 by approximately 60℃. The high temper resistance and thermal resistance of SDCM-S may be ascribed to the well stability of the precipitates of Mo₂C carbide during tempering. The thermal conductivity of SDCM-S is 1.86 times and 1.26 times higher than those of H13 at 100℃ and 700℃,respectively,which may be due to the low content of Si,Mn and Cr,as well as the high content of Mo of SDCM-S. The SDCM-S has better thermal fatigue resistance than H13 steel,i.e. the former one has a damage parameter of thermal fatigue of ca.76.1% of that of the later. In conclusion,SDCM-S has better performance in high temperature temper resistance,thermal stability,and thermal conductivity,which reasonably result in better thermal fatigue resistance of the steel SDCM-S.

The degradation performance of polyethylene(PE) induced by artificial thermo-oxidation aging at 80℃ was characterized as a function of its crystallinity in terms of the variation of tensile strength, tensile modulus, impact strength and chromatic aberration. The variations of carbonyl index, hydroxyl index, chain scission and crystallinity of the three as prepared PE with different crystallinities were comparatively examined by attenuated total reflection infrared spectroscopy (ATR-FTIR). The results show that during thermo-oxidation aging at 80℃, the PE with higher degree of crystallinity experiences significant decrease of tensile property, slow decrease of impact property and faster increase of chromatic aberration. The higher the crystallinity, the molecular chains of the PE prone to breakage in the early aging stage, but its oxidation is more noticeable during the later aging stage. The crystallinity of the PE with different crystallinities trands essentially unchanged after the first rise throughout the aging cycle. But the thermo oxidation-aging has greater influence on the crystallinity,which increases significantly for the PE with lower crystallinity.

The initial corrosion behavior and mechanism of 6061 aluminum alloy anodized in a solution of mixed boron-sulfuric acidswere studiedthrough outdoor exposure tests in industry-marine and northernsemi-ruralatmospheric environments at Qingdao and Beijing respectively by means of weight-loss measurement, mechanical property testand morphology observation of surface andfracture surface. The results show that after exposed in the industry-marine and the northernsemi-ruralatmospheric environment for one year, the average corrosion rates of the anodized alloy decrease 43.3% and 10.1%, respectively in comparison to the naked alloy, thus the anodic treatment impedes the corrosion and this effect is much efficient in the severer environment. The break elongation of the naked alloy exposed in industry-marine environment for one year decreases 35% in comparison with the original one, but the decrease for the anodized alloy is 23%. Therefore, the anodization with boron-sulfuric acid is not enough to prevent the plasticity deterioration of the alloy; correspondingly, ductile fracture of the surface layer has changed to brittle cleavage. Nevertheless, the above results provide an important reference to the corrosion and protection of aviation materials.

The influence of heating rate on the pyrolysis characteristics of a carbon fiber bidirectional sheet (T300-3000) in air stream was investigated by means of DTG-60(AH) TG/DTA simultaneous thermal analyzer. The results show that the thermal degradation behavior of the sheet was affected greatly by heating rate. The temperature related with the maximum mass loss rate shifted towards high temperature,and the distance between the two peaks of DTG curves was gradually larger and the peak areas increased with the increasing heating rate. The pyrolysis process of the carbon fiber bidirectional sheet can be divided into three stages including two decomposition stages of epoxy resin and one of the carbon fiber decomposition. The pyrolysis kinetics curves of the carbon fiber bidirectional sheet were analyzed by Kissinger method and Flynn-Wall-Ozawa method,and the acquired apparent activation energy and the apparent pre-exponential factor for different heating rates were of good accordance with each other. The thermostability of the carbon fiber bidirectional sheet with epoxy resin is relatively strong and controllable within a certain range of mass loss.

The effect of quench with two quenching media of 13% polyaleneglycol (PAG) and oil respectively on the high cycle fatigue behavior of spring steel 60Si2CrVAT was studied by applying alternatively uniaxial tension and compression. While the fatigue fractograph,source composition,microstructural evolution of the steel were examined by means of SEM,TEM and EBSD. The results indicate that the fatigue limit for the steel quenched with 13%PAG is 781.5 MPa; however that with oil is 714.0 MPa. Analysis results of fractograph show that fatigue damages mostly originate from the internal inclusions and carbides,while granular bright facets (GBF) are observed in the vicinity around the inclusions. Further investigation indicates that the stress intensity factor range at crack initiation site of inclusion ?Kinc trends to decrease gradually with increasing the fatigue life N_f,while the stress factor range at GBF boundary ?KGBF keeps almost constant with varying N_f and the ?KGBF for the steel quenched with oil is smaller than that with 13% PAG. From microstructural observation results,it suggests that the beneficial effect on the fatigue property of the steel quenched with 13%PAG is caused by that there existed much more nano-twins,much finer individual lath and block,as well as finer carbides uniformly distributed in martensitic matrix for the steel quenched with 13% PAG rather than those with oil.

Carbon fiber/Mg-alloy composites were fabricated by powder metallurgy technique using short carbon fibers without and with electroless plated Ni-coating as reinforcer and AZ91D powder as matrix．Then their interfacial morphology, elemental composition,mechanical properties and damping capacities were characterized by means of SEM,TEM-EDS,tensile tests and dynamic mechanical analyzer (DMA)．Results shows that the carbon fibers are uniformly distributed in the composites and preferentially oriented paralleling to the extrusion direction．The Ni coating improves the wettability between the carbon fibers and AZ91D matrix. Based on the strain spectrum by different frequency strain and G-L characteristic line, it follows that there should be a damping mechanism other than the known dislocation damping mechanism for the composite. With the increasing strain frequency, the control step for the damping performance of composite changes mainly from interface slip to dislocation. The damping capacity of Ni-coated carbon fiber reinforced magnesium matrix composites increase with the rising temperature. One damping peak exists in the range of 250~300 ℃.The peak temperature moves to higher temperature with the increasing frequency,which shows the characteristics of the thermal activation of relaxation process. According to the Arrhenius formula the calculated thermal activation is 3.448 eV.