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Thermal barrier coatings (TBCs) are facing the challenge of chloride salt hot corrosion in the marine environment. In the manuscript, 7YSZ feather-like columnar structure coatings were prepared by plasma spray-physical vapor deposition (PS-PVD). The Al2O3-modification based on in-situ synthesis was used as the strategy to improve the hot corrosion resistance of the coating. Then, the coatings were subjected to test of 900 °C NaCl thermal exposure and combustion gas-salt spray ablation. The microstructure and phase evolution results of the coatings show that NaCl has a strong corrosive effect on the as-sprayed PS-PVD TBC and leading to catastrophic oxidation. In contrast to this, the Al2O3-modified coating shows good corrosion resistance. In the hot corrosion behavior of NaCl, the metal elements in the bond layer are rapidly oxidized and accumulated on the surface of TGO layer through the electrochemical corrosion mechanism, which makes the TGO thicken rapidly. After combustion gas-salt spray corrosion, the YSZ coatings sintered and the evolution of mechanical properties were analyzed. Compared with the initial sprayed state, the hardness of the as-sprayed coating and the Al2O3-modified coating increased by 13.04 GPa and 11.47 GPa, respectively. And the elastic modulus of as-sprayed coating and Al2O3-modified coating increased by 133.00 GPa and 129.60 GPa, respectively.

This paper aims to research the high-temperature oxidation behavior of TiC/Mo composite. Adding 5 wt.% TiC, Mo-based composite was prepared by Spark Plasma Sintering. The composite was oxidized at different temperatures (400°C, 600°C, 800°C, 1000°C and 1200°C) and times (5 min, 10 min, 20 min, 30 min and 60 min). When oxidation was at 400-1000°C for 20 minutes, the degree of oxidation intensifies with the increase of temperature, and TiO2 was observed at 1000°C. While the temperature was 1200°C, the oxidation rate gradually decreased with the increase of time. The result shows that the formation of TiO2 can inhibit the oxidation process.

The liquid-solid compound casting technology was used to produce the AZ91D/0Cr19Ni9 bimetal composite without and with hot dipping aluminium, respectively. The influences of Al coating on microstructures and mechanical properties of AZ91D/0Cr19Ni9 interface were investigated. The results showed that the mechanical bonding was obtained between AZ91D and bare steel 0Cr19Ni9 where a gap existed at the interface; the metallurgical bonding was formed between AZ91D and Al-coated 0Cr19Ni9, which could be divided into two different intermetallic layers: layer I was mainly composed of α-Mg+β-Mg17Al12 eutectic structure and a small amount of MgAl2O4, and layer II mainly comprised of Fe2Al5 intermetallic compound. Furthermore, the hardness value of interface was obviously higher than that of AZ91D matrix, and the average hardness values of layers I and II were HV 158 and HV 493, respectively. The shear strength of AZ91D/Al-coated 0Cr19Ni9 interface was higher than that of AZ91D/bare 0Cr19Ni9 interface, which confirmed that Al coating could improve the adhesive strength between AZ91D and 0Cr19Ni9 during liquid-solid compound casting process.

In this study, the bronze-matrix/x-graphite (x = 0, 1, 3 and 5%) composites were fabricated by powder metallurgy route by using Cu-coated graphite, Ni-coated graphite and pure graphite, respectively. The microstructure, mechanical properties and corrosive behaviors of bronze/Cu-coated-graphite (BCG), bronze/Ni-coated-graphite (BNG) and bronze/pure-graphite (BPG) were characterized and investigated. Results show that the Cu-coated and Ni-coated graphite could definitely increase the bonding quality between the bronze matrix and graphite. In general, with the increase in graphite content in bronze-matrix/graphite composites, the friction coefficients, ultimate density and wear rates of BPG, BCG and BNG composites all went down. However, the Vickers microhardness of the BNG composite would increase as the graphite content increased, which was contrary to the BPG and BCG composites. When the graphite content was 3%, the friction coefficient of BNG composite was more stable than that of BCG and BPG composites, indicating that BNG composite had a better tribological performance than the others. Under all the values of applied loads (10, 20, 40 and 60N), the BCG and BNG composites exhibited a lower wear rate than BPG composite. What is more, the existence of nickel in graphite powders could effectively improve the corrosion resistance of the BNG composite.

The joining of arc sprayed Al-Zn coating and AZ91D substrate was achieved by solid-liquid compound casting. The microstructure evolution and formation mechanism of the interface were investigated in this study. A scanning electron microscopy (SEM), an energy dispersive spectroscopy (EDS), and an X-ray diffraction (XRD) were used to analyze the microstructure of the Al-Zn/AZ91D interface, whose results showed that the interface could be divided into three different intermetallic compound layers, which confirmed that the bonding between arc sprayed Al-Zn coating and AZ91D substrate was metallurgical. Among the three layers, the layer adjacent to the AZ91D substrate was mainly composed of δ-Mg, Mg 17 (Al, Zn) 12 and a small amount of lamellar Φ-Mg 21 (Al, Zn) 17 intermetallic compounds. The layer which was close to the Al-Zn pseudo-alloy coating mainly consisted of δ-Al, Al 2 Mg 3 Zn 3 and a small amount of oxides. The intermediate layer was mainly comprised of τ-Mg 32 (Al, Zn) 49 intermetallic compound. Furthermore, the microhardness values of interface zone were much higher than that of AZ91D substrate.

Magnesium alloy is honored as green engineering material for its low density, high specific strength, high specific rigidity, well cutting processing property, well electromagnetic shielding property, heat conduction and easy to recycle. In this paper, AZ31 Magnesium alloy sheet at difference thickness were prepared by symmetric and asymmetric rolling employed with six-roller mill. Microstructure of the two kinds of rolling magnesium alloy thin sheets at 0.5mm thickness were investigated. The grain distribution of AZ31magnesium alloy sheets made by asymmetry rolling at room temperature are more uniform than those made by symmetry process. The grains made by asymmetry are more tiny and the tensile strength and elongation increased obviously and the mechanical properties got better. At room temperature, value of n increased. Large value of n benefit to stamping forming. At room temperature, the value of LDR of asymmetry rolling sheets is 1.26, which was higher than symmetry rolling. So asymmetry rolling benefits to stamping forming.

A new Dy3+/Na+ co-doping system was attempted for improving the thermoelectric properties of CaMnO3 system in this paper. [Ca1-x(Na1/2Dy1/2)x]MnO3 samples were produced by the solid state reaction method, and the electrical properties and the microstructure were investigated. The X-ray diffraction data and tolerant factor were obtained, indicating the second phase and the geometric distortion in this system. Besides, compared with the resistivity and the Seebeck coefficient of single Dy-doped system, Dy3+/Na+ co-doping method could partially decrease the variation of carrier concentration as our expectation. More specifically, the holes introduced by doping Na+ could compensate electrons introduced by doping Dy3+, leading to a low variation of carrier concentration. As the result, a relatively high Seebeck coefficient (−251.6 μV/K) and a relatively low resistivity (8.7 mΩ cm) were gained in this system, and the highest power factor value of 298.0 μW/K2m was obtained at 323 K in [Ca0.95(Dy1/2Na1/2)0.05]MnO3.

P-type transparent conducting SnO thin films were directly fabricated using RF magnetron sputtering. The electronic properties of the SnO thin films were enhanced by Na ion implantation and annealing at 200°C. The growth and implantation conditions were systemically investigated. The electronic properties, optical properties, microstructure and surface morphologies of the films were characterized. It was observed that the structure of the Na-doped SnO films was crucial to improving their p-type conductivity.

Monolithic SiO2-TiO2 aerogels were prepared via supercritical drying using tetraethoxysilane and tetrabutyltitanate as precursors and ethanol as solvent. Influence of the heat-treatment on the microstructure and properties of SiO2-TiO2 aerogels were investigated in detail. The results showed that the as-prepared SiO2-TiO2 aerogels had low densities, high specific surface areas, small average pore diameters, and three-dimensional nanoporous structures. The anatase TiO2 phase of SiO2-TiO2 aerogels could form during supercritical drying process, and the transition to rutile TiO2 phase occurred after experiencing 1200°C for 2 h. SiO2-TiO2 aerogels containing 30 wt% TiO2 (ST3) still presented relatively high specific surface area of 451 m2/g even they undergo the treatment of 1000°C for 2 h. And the SEM images indicated that the agglomerated particles derived from ST3 appeared gradually to some extent. The glassy luster of ST3 heat-treated at 1200°C for 2 h illuminates SiO2 started to vitrify. Besides, the thermal conductivity of ST3 at room temperature is up to 0.03257 W·m-1·K-1.

A Cu2ZnSn(S,Se)4 (CZTSSe) absorber for thin film solar cells was fabricated by nonaqueous thiourea–metal–oxygen sol–gel processing followed by post-selenization. The effects of selenization temperature, selenization time and metal composition on the film microstructure and phase were investigated. Under optimized process parameters, the complete CZTSSe solar cell devices produced efficiency values as high as 8.08% with a short-circuit current density of 32.78 mA cm−2, an open-circuit voltage of 487 mV, and a fill factor of 51%. The factors that limit the device performance were discussed. The nonuniform film thickness and nonhomogeneous chalcogen components should be responsible for the low shunt resistance and thereby low open-circuit voltage; and the presence of a large number of voids and thick Mo(S,Se)2 interface layer may be the main reasons for high series resistance, detrimental to short-circuit current density and fill factor.

Perovskite type Ca1−xDyxMn1−xNbxO3 ceramics (x≤0·10) are synthesised by solid state reaction. Microstructures are characterised, and the thermoelectric properties are evaluated between 300 and 1100 K. The samples obtained in this work have high relative densities. The electrical resistivity shows a typical metallic conductivity behaviour and decreases with substitution, the variation of which is not significant in whole measured temperature range. The Seebeck coefficients are negative, indicating n type conduction, and the largest value is obtained, −174 μV K−1, at x = 0·02. The highest power factor is 258 μW (K2 m)−1 for the x = 0·02 sample. A maximum ZT value reaches 0·08 for electron doped Ca0·98Dy0·02Mn0·98Nb0·02O3 at 973 K, which is about twice as high as that of undoped CaMnO3.

In this work, fine-lamellar structured TiB2 ceramic wettable cathode coatings were deposited on carbon cathodes of aluminium oxide reduction cells by atmosphere plasma spraying (APS). Cathode carbon blocks consisting of coatings 800 μm thick of plasma sprayed TiB2 finepowder on carbon substrate were fabricated. In order to investigate the results of coating, the microstructure and phase composition of the wettable cathode coating were characterized by scanning electron microscopy (SEM). It is found that TiB2 fine-powders were partly oxidized during the plasma spraying process. The coating was mostly formed by a matrix of fully molten particles where the presence of semi-molten feedstock agglomerates. The APS method is believed to be a good choice to deposit TiB2 wettable cathode coating with high performance and reliability.

As a new technology, Atomil Force Microscopy (AFM) is being used in the research of microscopic structure on coal surface in recent years. By this technology, we can observe the nanoscale pore and crack shape of coal surface, and meas- ure some structural parameters. Different metamorphic grades produce different feature of surface microscopic structure of coal. This paper analyzes the surface microscopic structure of different metamorphic grade coal by AFM. The results show that the coal surface microstructure has a trend from rough to smooth with the increasing of metamorphic grade. The low rank coals contain large or medium pores and the high rank coals contain micro pores. The values of surface morphology characteristic parameters (Sq and Sa) nonlinearly decrease with the increasing coal rank. That is, the coal surface becomes smoother during coalification.

Series of a-Si:H/a-SiNx multilayers were prepared by very high frequency plasma enhanced chemical vapor deposition system. As-deposited samples were thermally annealed at the various temperatures. The effects of thermal annealing on the properties of luminescence were investigated. The photoluminescence intensity of the film annealed at 600 °C is found to be higher than that of the film without annealing. However, with further increasing the annealing temperature from 600 °C to 800 °C, the photoluminescence intensity of the film rapidly decreases. Fourier transform infrared spectroscopy and Raman-scattering spectroscopy were used to study the changes of the microstructures and bonding configurations. Based on the measurements of structural and bonding configurations, the improved photoluminescence intensity is attributed to the forming of radiative defect states caused by the effusion of hydrogen in the films.

Due to low-density, higher elevated temperature strength and good oxidation resistance; the Nb-Ti-Cr-Al alloy was estimated to become a new kind of material used at elevated temperature of next generation. Therefore, it was widely studied by western developed country, but there are still many questions unsolved in this area. In this article, several kinds of Nb-Ti-Cr-Al alloys of different compositions were prepared by arc melting, and analyzed by metallographic method, XRD, SEM and EDS. The results indicated, in Nb-40Ti-15Al alloy, the solidified Structure was typical small equiaxed grains, columnar crystals and common equiaxed crystals. And in Nb-40Ti-10Cr alloy, there is a serious coring segregation of Cr element; it can induce intergranular fracture of ingot. As the content of Cr element increased, constitutional supercooling occurred in solidification process, and the microstruture changed from straight crystal boundary to dendrite, such as Nb-40Ti-20Cr alloy. As for Nb-40Ti-10Cr-10Al alloy, the addition of Al and Cr lead to a great number of sub boundary and precipitated phase, and the microsegregation in alloy are also reduced to a certain degree. To sum up, the content level of Cr and Al is essential to both the microstructure and mechanical performances of Nb-Ti based alloys.

A detailed investigation of the effects of Nd on the microstructure, mechanical properties and electrochemical properties of lead anode in 160g.L-1 at 35°C was carried out. Galvanostatic polarization and Chronopotentiometry (CP) were used to study the electrochemical behavior ( such as anodic potential, corrosion rate and the composition of passive film) of the Pb and Pb-Nd anodes. The metallographic structure and passive film morphology of Pb and Pb-Nd anodes were observed and analyzed using polarizing microscope and scanning electronic microscopy (SEM), respectively. The experimental results show the grains become smaller and aggregation of PbxNdy become severe as the content of Nd increases. The addition of Nd enhances the formation of PbO2, inhibits the formation of PbSO4 and PbO and reduces the anodic potential. However, Holes presenting on rough passive film of high Nd content Pb-Nd anodes accelerate the corrosion.

The microstructure and properties of 600MPa grade steels produced by isothermal treatment has been studied. The influence of isothermal treatment temperature on the microstructure of steels has been investigated by the aid of Optical microscopy and TEM. The results show that after various isothermal treatments the microstructure of steels varies with the isothermal temperature. When the temperature is lower than 530°C the microstructure is mainly composed of granular bainite and lath bainite. Whereas when the temperature is higher than 580°C the polygonal ferrite and quasi polygonal ferrite appears and the microstructure consists of ferrite and fine lath bainite. Since the microstructures are complex and the yield ratio of steels under these conditions are all lower than 0.8. The strength of sample for 630°C isothermal treatment is the highest. The yield strength is over than 800MPa and the tensile strength is over than 1000MPa due to the fine precipitates containing copper. These copper containing precipitates formed during the isothermal transformation by the way of inter-phase precipitation.

A new type of double pore size activated alumina/activated carbon multiphase material was made by using waste aluminum slag and activated carbon as main raw materials. The microstructures and pore size distribution of the new material were characterized by SEM and BET techniques. Iodine adsorption value was used to evaluate the adsorption performance of the multiphase materials, and the benzene adsorption capability was also measured. The results show that the specific surface area of the activated alumina/activated carbon multiphase materials is 261.95m2/g, pore volume can reach 0.25m3/g, and the iodine adsorption value is 381.97mg/g. BET pore size distribution shows that micropores and mesopores both exist in the composite material. The micropores range from 0.6 to 1.4nm, and the mesopores range from 3.0 to 7.0nm. The benzene adsorption capability of this new material is excellent, with a saturated adsorption capacity of 241.00 mg/g, much better than pure activated alumina or activated carbon.

Several Nb-Ti-Al based alloys have been investigated by X-ray diffraction (XRD) and optical microscope (OM). It was found that the morphology of the B2/β phase was different from the O phase (Ti2AlNb) and δ phase (Nb3Al). The B2 phase can not be separated from the disordered β phase by metallography and XRD easily. And the typical morphology of O phase alloy is large herringbone structure. After that the aberrance of the lattice parameters was discussed in this article. The present result indicates in these alloys the lattice parameters were mainly determined by the ratio of Nb to Ti. As the ratio of Nb to Ti in alloys increased, the lattice parameters increased too.

The ingot of Ti47Al alloy was prepared by a newly developed rapid directional solidification, the microstructure and compressive properties of the ingot was observed and tested. The results show that the macrostructure consisted mainly of coarse columnar grains parallel to the axial direction, with the size of 0.5mm wide and 10mm in length. The direction of lamellar is almost perpendicular to the growth direction in the longitudinal section and no dendritic core is found. The average ultimate compressive strength of the specimens with grain growth parallel/perpendicular to the compressive direction is 1233.3 and 861.7 MPa respectively. The fracture mode for specimens with grain growth parallel to the compressive direction exhibits predominantly translamellar fracture, however, that for specimens with grain growth perpendicular to the compressive direction exhibits predominantly delamenation or interlamellar fracture.

The composites in the MgO-Al2O3-Fe2O3 system were prepared using high pure magnesia and alumina as raw materials and ferric oxide powder as additive. The effect of sintering temperatures on the sintering performance and thermal shock resistance of the composites was studied. The results showed that both the apparent porosity and linear change ratio of the samples decreased with the increase of sintering temperatures, and their bulk density and bending strength increased accordingly. The sample sintered at 1550°C exhibits excellent thermal shock resistance. The XRD and SEM results indicated that the crystal phase of the samples remained the same, but their microstructure became denser as the sintering temperatures increased from 1500°C to 1600°C. As a result, the composites could be sintered at about 1550°C, which has a potential application in cement rotary kiln linings.

Microcrystalline silicon (μc-Si:H) film deposited on silicon oxide in a very high frequency plasma enhanced chemical vapor deposition with highly H2 dilution of SiH4 has been investigated by Raman spectroscopy and high resolution transmission electron microscopy. Raman spectroscopy results show that the crystalline volume fraction increases with increasing the hydrogen flow rate and for the hydrogen flow rate of 160 sccm, the crystalline volume fraction reaches to 67.5%. Nearly parallel columnar structures with complex microstructure are found from cross-sectional transmission electron microscopy images of the film. The temperature depend dark conductivity and activation energy are studied in order to investigate the electronic transport processes in the nc-Si films.

A novel precision casting technique for TiAl based alloy was described in this work, called the permanent mold suction casting technology，and the blades of Ti-47Al-2Si、Ti-47Al-2W-0.5Si、Ti-47Al-2W-0.5Si -0.5B were get by this technology. The structures of these blades were studied. The results of this study indicate that microstructure is sensitive to heat treatment and composition. The average grain size is 30 um before heat treatment. The grain size of TiAl based alloy is grossed by heat treatment at 1573 for 5h and furnace cooling, especially Ti-47Al-2Si. The addition of boron, the grain size of Ti-47Al-2W-0.5Si-0.5B is smaller than Ti-47Al-2W-0.5Si. The γ-TiAl based alloys have equiaxed grain in cross section, but the surface microstructure of γ-TiAl based alloys have more fine equiaxed grain than inside due to high cooling rate of mold.

Microstructure evolution of peritectic Al-25at.%Ni alloy during directional solidification with pulling velocity ranging from 2 to 500m/s is investigated. The directional solidified alloy is composed of Al3Ni2, Al3Ni phase and eutectic (Al3Ni+Al) phase. When pulling velocity ranges from 2 to 5m/s, Al3Ni phase grows into an integral matrix. Majority of primary Al3Ni2 is consumed by peritecti reaction and transformation behind the peritectic interface with pulling velocity ranging from 2 to 20 m/s. While pulling rate increases, major Al3Ni phase direct solidifies from liquid. With cooling rate increasing, Al3Ni2 phase content firstly decreases and then increases, while the Al3Ni phase content decreases throughout.

Systematic directional solidification experiments were carried out in Fe–Ni peritectic alloys to investigate the influences of peritectic reaction on the microstructures evolution. Various microstructures were observed in the directionally solidified samples, such as bands, mixed bands, island banding, tree-like oscillatory pattern, coupled and cellular coupled growth structures. It was found that peritectic reaction occurs near the trijunctions during the two-phase growth at different interface morphologies of the primary phase observed as planar, cellular and dendritic. Peritectic reaction makes the liquid/δ/γ trijunctions region quite irregular and makes the trijunctions dynamics quite complicated, and thus plays an important role in the formation of various microstructures.

The microstructure evolution of Ti-Al peretectic system in transient stage and steady state in directional solidification was predicted via theoretical analysis. The solute distribution controlled by diffusion at and ahead the solid-liquid interface will determine whether the properitectic and peritectic phases can nucleate and grow ahead of the opposing solid phase. The formation of banding structure is possible in a certain composition range. At the steady state, a microstructure selection map was set up based on interface response function model. The microstructure of TiAl alloys with different aluminum content was studied with Bridgman directional solidification method. Some evidence in the experiment has been found to support the theoretical prediction.

The microstructure and phase constitution near the interface of diffusion bonding in Mg/Al dissimilar materials were researched by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM). The test results indicated that an obvious diffusion zone was formed near the Mg/Al interface during the vacuum diffusion bonding. The diffusion transition zone near the interface consists of MgAl, Mg3Al2 and Mg2Al3 phases. The transition region on the Mg side mainly consists of Mg crystals, and the new phase formed was Mg3Al2 with a face-centered cubic lattice. This is favorable for improving the combination strength of the Mg substrate and the diffusion transition zone.

A multiscale model is developed for simulating the microstructure evolution during solidification processes of Ti-6Al-4V alloy in vertical centrifugal casting, which combines the 3D finite difference method (FDM) at the macroscale with a 2D cellular automaton (CA) model at the microscale. The macro model is used to simulate the fluid flow, mass, heat and species transfer throughout the casting under centrifugal conditions. The micro model is used to predict the nucleation and growth of microstructures for the vertical central plane. A semi-coupled scheme between the 3D macroscopic and 2D microscopic calculations is adopted. Based on the CA cell, a modified method for simulating the shrinkage cavity is given. With the proposed model, numerical simulations are performed to investigate the influences of mould rotation speed, superheat, and mould material on microstructure formation. Calculated results reveal that the equiaxed zone is found to expand with increasing the mould rotation speed, as well as decreasing melt superheat and heat diffusivity of mould. The role of rotation speed is much greater than that of superheat and mould material in centrifugal casting. The underlying mechanisms responsible for those physical phenomena are discussed.

A TiAl sheet fabrication technique from Ti/Al foils was studied experimentally. Firstly, the reaction sequence between Ti and Al foils were studied with DSC and then a three stage solid transformations processing was carried out. At the first stage, Al diffused into Ti foils and formed Al3Ti. The heating temperature was selected based on a ruler that the pure Al was consumed by solid diffusion with a short time and avoiding the melting of Al. The resulted microstructure consists of pure Ti and Al3Ti. At the second stage, part of Al in Al3Ti diffused into pure Ti and formed the high temperature phase. At the third stage, the sample was heated into the high temperature -phase zone and hold a given time and then cooling with the furnace. A full density γ-TiAl based alloy sheet with lamellar microstructure was successfully fabricated under above processing. The lamellar orientations are aligned around 0-45o compared to the longitudinal direction of the sheet.

TEM was used to investigate the microstructure of the laser alloying zone on 65Mn tape-steel surface. The composition of this zone was designed on the basis of M2 high speed steel. The studies indicated that the structure of the laser alloying zone was significantly different from that of a normal M2 steel. Martensite laths dominated and a great amount of highly dispersed granular or short stick-like M6C carbides present. Moreover, there was a ball-like noncrystalline phase in some regions.

Physicochemical phenomena at the polymer-metal interface have been observed by the use of surface-enhanced Raman scattering (SERS). SERS spectra are compared with the infra-red reflection-absorption spectra for coatings of polymer on metals. Results show that SERS is an effective in situ analytical technique which is highly informative in that the authentic adsorption state and the microstructure of the first monolayer near the metal surface can be revealed with much less interference from the polymer bulk.