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Since it was first time proposed, the Space Solar Power Station (SSPS) has attracted great attention all over the world, which is a huge space system and provide energy for Earth. Although several schemes and abundant studies on SSPS have been proposed and conducted, it is still unrealized. The reason why SSPS is still an idea, not only because it is a giant and complex project, but also due to the requirement of various excellent space materials. Among the diverse required materials, we believe energy materials are the most important. Herein, we reviewed the space energy conversion materials for SSPS.

In this paper, we investigated the porosities and their formation mechanism in the nickel-base superalloy powders, which were prepared by electrode induction melting argon atomization and divided into four particle size ranges: d＜60μm, 60μm≤d＜120μm,120μm≤d＜180μm, and d≥180μm. Firstly, the distribution of porosities in the powder were observed by Zeiss electron microscope. Secondly, the number and size of porosities in different particle size range were counted. Finally, the formation mechanism of the porosity was analyzed in details. The results show that the porosities are mainly distributed at the edge and center of the powders, and the size increases with the increase of the powder size. the porosity varies from a few microns to dozens of microns. the biggest pore size in the powder is approximately 120μm.There are no obviously porosities found in powders when their diameters are less than 60μm. While the porosity appeared as the powder diameter is more than 60μm. In addition, the proportion of the powder with porosities also increases with increasing powder size. When powders size is more than 180μm, the proportion of the powder with porosities reached about 91%. In general, the formation of porosities in powders are mainly ascribed to two reasons. the first one is a portion of argon was enclosed by the metal films during the spheroidization; the second one is the metal droplets uneven shrinkage during the solidification.

A crucible-free, an Electrode Induction melting Gas Atomization (EIGA) technique for induction melting of the reactive and refractory metals/alloys is developed. The impedance matching of the superalloy Rene95 in a conical induction has been investigated. An evaluation of the complex electromagnetic and thermal fields on the free surface of the superalloy Rene95 is carried out by both numerical and experimental methods under alternating currents with the output power of 120 kW and operational effective current 2 kA. The two types of coupling induction coils have been devised, tested and compared with the experimental results, revealing the impedance of four-turn induction coil with superalloy Rene95 releasing the electrical energy that causes the most high-temperature distribution in the surface of superalloy Rene95. Induction coil is also known as an “inductor” which is the core component in the melting process of nickel-based superalloy, leading to design a good induction coil to reduce the power consumption and increase the efficiency of the process. The achievements are the melting rate enhancement and a steady-state of continuous liquid metal flow producing the liquid metal streams with diameter of about 5 mm.

Rare earth elements (REEs) are a vital modifier in tool & die steel. Their effects on the phase transformation behavior, microstructure characteristics and property of as-cast T15 high-speed steel (HSS) were investigated by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD), differential scanning calorimetry (DSC) and dilatometry. The experimental results show that the as-cast microstructure of samples is refined and ameliorated after adding REEs, and the total quantity of eutectic carbides with hard and brittle properties is significantly reduced, which contribute to lower Rockwell hardness levels and higher bending strength. The morphology of grain boundaries carbides turns from lamellar to blocky polygonal. During the reheating process, REEs can reduce the thermal expansion coefficient of studied steel before austenitizing and promote the dissolution of alloying elements into austenite matrix. During cooling, REEs delays the occurrence of phase transformation, but it is favorable to the increase of the expansion amount of martensite transformation. Additionally, the microhardness value also increases with the increase of cooling rate. When the cooling rate is 20 °C/s, the full martensite transformation will occur and the microhardness of HSS1 reaches the maximum value of HV738, greater than that of RE-free HSS0 (HV701).

A new method (electrode induction gas atomization, EIGA) of producing high-speed steel powder was preliminarily studied by a combination of numerical simulation and experiment. Based on COMSOL Multiphysics® software, the effect of various parameters including coil angle, output frequency and power of the electrical source on flux density, induced current, temperature field and phase field was simulated. Meanwhile, the experiment was carried out on the EIGA device to produce high-speed steel powder. The results of FEM simulation indicate that when the coil angle is 30°, there is the highest thermal efficiency on the electrode cone, and the induced current and temperature will increase as the output frequency and power of the electrical source increase. In addition, the powder experimentally obtained by the EIGA method exhibits good particle sphericity regardless of the size, with a median diameter (D50) of 71.4 μm and a low oxygen content of 81 μg/g. The phase composition of the powder is mainly composed of γ-Fe and α-Fe structures and MC-type carbides. Due to the faster cooling rate, a solidification microstructure consists of fine cellular crystals and dendrites, and no coarse eutectic carbide network is observed, also confirmed by EDX elemental mapping.

W/Ni/Fe alloy coating with different tungsten (W) content were prepared on CuCrZr substrate by cold spray (CS) process. The coating's surface and cross-section morphologies were investigated by scanning electron microscope. Results demonstrated that the CS W alloy coating was compact, voidless, crackless and free from impurities. The cohesive strength of CS W/Ni/Fe alloy coating was higher than 30 MPa. The coating's maximum Vickers hardness was measured to be 528 HV. The minimum porosity of deposit was measured to be 0.1%. Its maximum thickness can reach up to 1.9 mm when graded method was applied. The thermal shock cycles of graded coating can reach up to 330 and 46 at 500 °C and 800 °C respectively.

The hot deformation and densification behaviors of sintered P/F-10C50 steel were investigated by hot compression tests on Gleeble-1500 thermal mechanical simulator at the temperature ranging from 900 °C to 1000 °C and the strain rate ranging from 0.1 s-1 to 10 s-1. The flow and densification characteristics of the tested specimens at different deformation temperatures and strain rates were studied. The flow stress of the sintered steel persistently increases until the end of the test as the result of matrix and geometric work hardening. The higher deformation temperature and strain rate are conductive to the healing of the pores and promote the densification of the sintered steel, while the higher deformation temperature and lower strain rate impede the densification. The constitutive equation of the sintered steel is established by the means of stepwise regression. The flow stresses predicted by the established constitutive equation are in good agreement with the experimental values, and the correlation coefficient (R) and the average absolute relative error (AARE) are 0.9931 and 3.52%, respectively. These results demonstrate the hot deformation behaviors of the sintered P/F-10C50 steel are excellently predicted by the established constitutive equation.

To investigate the hot deformation behavior of powder-forged (P/F) Fe-0.5C-2Cu steel, the hot compression tests were conducted at temperatures ranging from 900 to 1000 °C and strain rates from 0. 1 to 10 s−1 using Gleeble-1500 thermal simulator. The true stress-true strain curves at different temperatures and strain rates of P/F steel were obtained. It is found that dynamic recovery only occurs as strain rate is 10 s−1 at 900 °C, and the dynamic recrystallization is the main softening mechanism. The flow stress increases with decreasing temperature and increasing strain rate. The experimental data are employed to develop constitutive equations on the basis of the Arrhenius-type equation by introducing the strain with nonlinear fitting. The flow stresses predicted by the proposed constitutive equations are in good agreement with the experimental values, and the correlation coefficient (R2) and the average absolute relative error (AARE) are 0.99525 and 3.07 % respectively. These results indicate the proposed constitutive equations can effectively describe the hot deformation behavior of the material.

Copper matrix composites consisting of chromium (Cr) or ferrochrome (Cr-Fe) as strengthening elements and molybdenum disulfide as a lubricant had been sintered in nitrogen and hydrogen atmosphere, respectively. Their morphology and energy-dispersive X-ray spectrometry (EDS) analysis showed that serious interaction occurred between MoS2 and Cr (or Cr-Fe) particles when the samples were sintered in hydrogen atmosphere. Chromium sulfide compound (Cr x S y ) was formed as a reaction product, which decreased the density and strength of the composites remarkably. This interaction was inhibited when the samples were sintered in nitrogen atmosphere; thus, the mechanical properties of the composites were improved.

The flow behavior of spray-formed FGH95 superalloy (similar to Rene 95) was investigated at temperatures ranging from 1050 to 1 140 °C and strain rate ranging from 0.01 to 10 s−1. At a given temperature and strain rate, flow stress increases quickly with increasing strain and then reaches a peak, then gradual decreases until high strain, and dynamic softening is observed. Utilizing the hyperbolic sine function and introducing the strain with nonlinear fitting, the revised constitutive equations incorporating the effects of temperature, strain rate and strain for high temperature flow stress prediction of superalloy were established. The revised constitutive equations were implanted into finite element software by second development to simulate the hot compression process successfully, and the effective stress and load stroke curves obtained by numerical simulation are good agreement with the experimental results.

in this work, two kinds of boron carbide coating based on copper substrates, which are non-FGM B4C/Cu coating and FGM B4C/Cu coating, have been fabricated successfully. It is found that the chemical sputtering yield of B4C measures by LAS2000 apparatus is much lower than that of SMF800 graphite under the conditions of 3keV, 4.6E 15D+ /s/cm2 irradiation, and that FGM-B4C coating has much better performance than non-FGM-B4C coating in thermal shock tests. Thermal desorption performance and physical sputtering damage after plasma irradiation are also evaluated.

Based on the experimental data from hot compression tests on Gleeble 1500 thermal simulator, the revised constitutive equations of spray-formed FGH95 superalloy considering the effect of strain on the material constants were established. The average absolute relative error (AARE) was employed to verify the validity of the constitutive equation, and the value of AARE is 3.85 %. Subsequently, the revised constitutive equations were successfully used to simulate and analyze the deformation behavior, stress distribution, forming loads and temperature distribution in both dies and billet during the isothermal forging process of turbine disk of large dimension (about 400 mm in diameter) by the means of finite element method (FEM). Moreover, the optimum process parameters are 1,120 °C of forging temperature and 0.01 s−1 of strain rate for the spray-formed FGH95 superalloy turbine disk.

The potential of spray forming for microstructural refining can be attractive to the production of superalloys. A f200 mm spray formed FGH95 superalloy round billet that was produced using a single atomizer has considerably homogeneous, small, equiaxed grains. The measured oxygen content is 2×10−5, and the measured porosity is only 0.6%. The achieved yield of deposit is in a good range of about 73. 6%. The microstructure and tensile properties of nickel-based spray formed FGH95 superalloy are analyzed. Also, effects of heat treatment on microstructure were discussed. The results show that the spray formed FGH95 superalloy has higher isotropy in tensile property due to its γ′ phase homogeneous distribution and less defects in the microstructure. Regarding processing procedures, the different heat treatment processes affect the microstructure and γ′ phase homogeneous distribution of spray formed FGH95 superalloy.

Sintered and forged powder metallurgy (P/M) steels were subjected to tensile, hardness and impact test, in order to understand the influence of the microstructure on the mechanical properties and fracture behavior. Ultimate tensile strength, yield strength, elongation, reduction in area, hardness and impact toughness all increase with a decrease in porosity. With the increase of density, the mode of fracture change from pure ductile in sintered necks of the material to complete brittle from fully dense pearlitic grains.

Tungsten coating is considered as a promising alternative material for plasma facing materials (PFC) in future fusion devices. The electro-deposition of tungsten in Na2WO4-ZnO-WO3 melt at 1173 K on low activation steel substrates was studied in this work. Adherent and smooth tungsten films were deposited under various pulsed current conditions. The crystal structure and microstructure of tungsten deposits were characterized by XRD, SEM and EDX techniques. The results show that pulsed current density and duty cycle have a significant influence on tungsten nucleation and electro-crystallization phenomena. Uniform and smooth tungsten coating with high purity and high adherence is obtained on low active steel substrates as cathodic current density ranges from 35 to 25 mA·cm−2.

The corrosion behaviors of CNS-I and modified CNS-II were evaluated by exposing to superciritical water (SCW) at 550 °C and 25 MPa with a dissolved oxygen concentration of 200 × 10−9 for up to 1000 h. Detailed corrosion results of these two alloys were provided, including the growth rate of the oxide scales, microstructure of the oxide scales, distribution of phases and alloying elements. The mass gains of CNS-I and modified CNS-II were 609.73 mg/dm2 and 459.42 mg/dm2, respectively, after exposing to SCW for 1000 h. A duplex oxide scale with an outer porous magnetite layer and an inner relatively dense magnetite/spinel-mixed layer was identified on CNS-I and modified CNS-II after the test. The oxide scales were rather porous at the beginning of the test but the porosity decreased with increase of the exposure duration. It was found that Fe was enriched in the outer oxide layer, Cr was enriched in the inner oxide layer and O existed at a very high concnetration in the whole oxide scale. Other alloying elements such as Mo, W, Mn were depleted from the outer oxide layer and showed slightly enrichment in the inner oxide layer. The distributution of Ni was different from other elements, it was enriched in the interface bewteen the base metal and the oxuJe scale and depleted in the outer and inner oxide layers.

Pure tungsten, oxide dispersion strengthened tungsten and carbide dispersion strengthened tungsten were fabricated by high-energy ball milling and spark plasma sintering process. In order to evaluate the properties of the tungsten alloys under transient high heat flues, four tungsten samples with different grain sizes were tested by high-intensity pulsed ion beam with a heat flux as high as 160 MW/(m 2 ·s −1/2 ). Compared with the commercial tungsten, the surface modification of the oxide dispersion strengthened tungsten by high-intensity pulsed ion beam is completely different. The oxide dispersion strengthened tungsten shows inferior thermal shock response due to the low melting point second phase of Ti and Y 2 O 3 , which results in the surface melting, boiling bubbles and cracking. While the carbide dispersion strengthened tungsten shows better thermal shock response than the commercial tungsten.

The hot compressive deformation behavior of the superalloy was investigated at the temperature range from 1050 to 1140 and strain rate range from 0.01 to 10s-1 on Gleeble-1500 thermal simulator. Utilizing hyperbolic sine function and introducing the strain with 4th order polynomial fitting, the constitutive equations of flow stress of spray-forming FGH95 superalloy at high temperature were established. The results show that during the hot compression deformation of the superalloy, the characteristics of dynamic softening were observed, and flow stresses decrease with increasing temperature and decreasing strain rate. The flow stress of the superalloy predicted by the proposed models with 4th order polynomial fit agree with the experimental value well, and the average relative error is 3.64%.

Modified CNS-Ⅱ F/M steel was designed for in-core components of supercritical water cooled reactor. Study on the hot deformation behavior of modified CNS- Ⅱ F/M steel is of great importance for processing parameter planning and microstructure controlling during hot deformation. The hot deformation behavior of modified CNS-Ⅱ F/M steel was investigated through isothermal hot compression test at temperature ranging from 1 223 to 1 373 K and strain rate 0.01 to 10 s^-1. The true stress true strain data gained from compression tests were used to built constitu- tive equation of modified CNS-Ⅱ F/M steel. The influence of strain on the accuracy of constitutive analysis was in corporated, assuming strain has a influence on material constants. A 5th order polynominal equation with very good accuracy was used to represent the influence of strain on material constant. The flow stresses calculated from the constitutive equation were compared with test values in the whole experiment range and the absolute average error for the constitutive equation in predicting fl.ow stress is 4. 728 %. At last, the recrystallization behavior of modified CNS-Ⅱ F/M steel was investigated. The relationship of critical strain and peak strain with Zener-Hollomon parameter were given by an experimental equation.

Ferritic/martensitic (F/M) steels have been recommended as one of the candidate materials for supercritical water cooled reactor (SCWR) in-core components use for its high thermal conductivity, low thermal expansion coefficient and inherently good dimensional stability under irradiation condition in comparison to austenitic steel. CNS-II F/M steel which has good mechanical properties was one of the 9-12Cr F/M steels designed for SCWR in the previous work. In this study a modified CNS-II F/M steel was used and it's ultimate tensile strength was 925 MPa at room temperature and 483 MPa at 600 °C after optimizing heat treatment parameter. The ductile to brittle transition temperature of modified CNS-II F/M steel is −55 °C. Those are at the same level or even higher than that of CNS-II and some commercial F/M steels nominated for SCWR in-core component use. The transmission electron microscope (TEM) results showed that the mechanical properties of the tempered martensite was closely related to the decomposition stage of the martensite.

The synthesis of thermo-responsive hydrogels poly(N-isopropylacrylamide )(PNIPAm) by frontal polymerization (FP) was carried out in four mixed solvents, i.e. dimethylsulfoxide (DMSO) mixing with water, ethanol, tetrahydrofuran (THF) and acetone, respectively. The influences of mixed solvent on frontal parameters, pore morphologies, swelling behavior of PNIPAm hydrogels were investigated. The pore of PNIPAm hydrogel synthesized in THF/DMSO was observed a big honeycomb cells, others were channel-like cells. Furthermore, the sample obtained in THF/DMSO had higher swelling ratio as compared to others, and the one synthesized in Water/DMSO showed the lowest. Above results indicated that fine-tuned poly(N-isopropylacrylamide) hydrogels can be prepared in short time and with easy protocol by adjusting mixed solvents in frontal polymerization process.

Nuclear fusion is a promising source of environmental friendly energy for the future, and the ultra-fine grained Tungsten (W) is a hopeful candidate material to be used as plasma-facing materials (PFMs), which are the key materials in the International Thermonuclear Experimental Reactor (ITER), for its many useful advantages. While, due to its high melting point and high sintering temperature needed, the ultra-fine grain sized tungsten is not easy to be fabricated. In this paper, the method of explosive consolidation of powders as well as its mechanism and improvements are discussed, and finally the possibility of using this method to preparing of ultra-fine grained W plasma facing material are also introduced.

In this article we present the testing, evaluation of infrared radiation properties of polycrystalline materials especially as cordierite-based glass-ceramics. Researches aim to make a comprehensive and systematic exposition of emissivity definition, test principles and test methods. And on the basis of measurement results of the infrared emissivity of cordierite-based glass-ceramics, the Infrared radiation property of this polycrystalline material was discussed. Research has a positive significance on the development of the infrared radiation heating and drying materials.

以SbCl 3 和Se粉为原料, 水合肼(N 2 H 4 ·H 2 O)为还原剂, 采用水热法在150℃下, 分别保温不同的时间合成Sb 2 Se 3 纳米粉末. 通过X射线衍射(XRD)、场发射电子扫描电镜(FESEM)、透射电镜(TEM)以及高分辨透射电镜(HRTEM)等分析方法对产物的物相成分和微观形貌等进行了表征, 实验结果表明保温时间达到24h时, 获得产物为单相Sb 2 Se 3 纳米线晶体. 根据实验结果还研究了水热合成Sb 2 Se 3 纳米线晶体可能的反应及生长机理, 结果表明一维纳米线沿[001]方向生长, 纳米线的形成与其独特的层状晶体结构有关. 最后采用放电等离子体快速热压烧结法将水热合成的Bi 2 Te 3 纳米粉末与不同含量Sb 2 Se 3 纳米线进行复合, 分析了Sb 2 Se 3 纳米线对Bi2Te3纳米材料热电性能的影响, 发现复合约1 at% Sb 2 Se 3 纳米线可以使Bi2Te3纳米材料热电性能有一定提高.

Ferritic/martensitic steels with Cr of 9% – 12% (in mass percent) are favourable candidates for fuel cladding tube and in-core components of supercritical water-cooled reactor. 9Cr-3WVTiTaN low activation ferritic/martensitic steel, designated as China Nuclear Steel- I (CNS- I), was patterned after T91 steel (modified 9Cr-1Mo) for the reactor. The idea of low activation material and microalloy technology was introduced into the design of the steel. The hardening, tempering and transformation behaviour of CNS- I steel was investigated. The steel has advantages in tensile properties at elevated temperature relative to zircaloy that has been widely used as cladding material for conventional light water reactors. CNS- I steel exhibits tensile properties and impact toughness comparable to T91 steel which exhibits availability in the present fission reactors and fast breeder reactor but includes undesired radioactive elements such as molybdenum and niobium.

Super-clean and super-spherical FGH4095 superalloy powder is produced by the ceramic-free electrode induction-melt inert gas atomization (EIGA) technique. A continuous and steady-state liquid metal flow is achieved at high-frequency (350 kHz) alternating current and high electric power (100 kW). The superalloy is immersed in a high-frequency induction coil, and the liquid metal falling into a supersonic nozzle is atomized by an Ar gas of high kinetic gas energy. Numerical calculations are performed to optimize the structure parameters for the nozzle tip. The undesired oxidation reaction of alloying elements starts at 1000 °C with the reaction originating from the active sites on the powder surfaces, leading to the formation of oxides, Me x O y . The role of active sites and kinetic factors associated with the diffusion of oxygen present in the atomization gas streams are also examined. The observed results reveal that the oxidation process occurring at the surface of the produced powders gradually moves toward the core, and that there exists a clear interface between the product layer and the reactant. The present study lays a theoretical foundation for controlling the oxidation of nickel-based superalloy powders from the powder process step.

Thermo-responsive hydrogels of poly(N-isopropylacrylamide) (PNIPAm) were prepared by fontal polymerization and investigated as a temperature-triggered delivery device for the model drug aspirin. The influence of relative amount of reactant components on the feature of the polymerization front was studied. Furthermore, aspirin was loaded into hydrogels prepared by fontal polymerization method and classical polymerization, respectively, and its release characteristics were determined under different temperature conditions (25 °C and 37 °C). The drug storages and kinetic parameters for two hydrogels indicated that drug-loading capacity and drug release of frontal polymerization (FP) hydrogel were improved as compared with the classical polymerization (CP) one. Scanning electronic microscope and differential scanning calorimetry (DSC) results could account for these improvements in drug delivery for FP hydrogel. The above results indicate that FP can be an alternative method for the preparation of PNIPAm hydrogels used as drug delivery devices with less time consuming and easier protocols.

Two kinds of W/Cu functionally graded material based high heat flux components, including monoblock concept and flat tile concept, are designed and fabricated. Thermally induced stresses and strains under operation conditions in these components are analyzed using finite element analysis. The effect on stress and strain of using different graded structures to join Cu to W is examined and compared. There has no obvious difference on operation thermal stress mitigating between monoblock design and flat tile design. The component with monoblock concept was fabricated by a one step fast resistance sintering, and the component with flat tile concept was fabricated by infiltration-welding method successfully.

The feasibility of 5 kg β-SiC synthesized in one batch was demonstrated through igniting the mixture of Si, C-black and polytetrafluoroethylene (PTFE) under different nitrogen pressures. The effect of experimental parameters, including the contents of PTFE, nitrogen pressure, preheating, and raw materials distribution forms were investigated. The results show that the products are β-SiC with equiaxed grains. The average grain size is less than 200 nm. The powders loaded loosely promote reaction heat dispersing, resulting in small grains. High purity β-SiC powders are obtained when the PTFE content is as low as 5wt%, which simplifies the process and decreases the cost effectively. The ceramic sintered from the obtained β-SiC powders presents the hardness of 22.20 GPa, the bending strength as high as 715.15 MPa and the fracture toughness of 8.179 MPa·m½, which are higher than those of ceramics fabricated with α-SiC produced by combustion synthesis.

Efforts to improve the thermoelectric efficiency of silicon–germanium alloys are discussed. These efforts are essentially focused on substantially enhancing carrier concentration levels and thus increasing the values of the power factor and the figure of merit of n-type Si95Ge5 alloys materials. A combination of (P + GaP) multi-dopants is used for this purpose. Very high carrier concentration levels and high electrical power factors were obtained in hot isostatically pressed materials. The good overall understanding of doping mechanisms which has been achieved should enable optimization of the thermoelectric properties over this extended carrier concentration range.

Tungsten has been decided as the plasma facing material (PFM) for some high heat flux regions of the divertor in the International Thermo-Nuclear Experimental Reactors (ITER). In this paper, our efforts concentrated on the functionally gradient W/Cu coating fabricated on the oxygen free copper by atmosphere plasma spraying under the inert gases protection. The functionally gradient W/Cu coatings were designed to relieve the thermal stress during the spraying processes. For comparison, the tungsten coatings were also deposited directly onto the copper substrates by the same technology. XRD, SEM and EDS were applied to identify the phases, morphologies and compositions of these coatings. Tensile tests were performed to measure the bonding strength between the coatings and the substrates. Furthermore, water quenching and high heat loading experiments using a pulse laser beam were also carried out to estimate the thermal shock properties of these coatings.

This paper reports some new progresses on layered and graded coatings for plasma facing materials in fusion devices in Laboratory of Special Ceramics and Powder Metallurgy (LSCPM), University of Science and Technology Beijing (USTB), China. They included tungsten coatings made be various particle sizes of initial feedstock and interlayers and boron carbide graded coatings. All the coatings were fabricated on the oxygen free copper by plasma spraying. The microstructures and properties were investigated for PFM. Water quenching and high heat loading experiments were also carried out to estimate the thermal performance of these coatings.

Selective laser sintering (SLS) of Si3N4 and Al2O3 powders were investigated in this work. Copolymer was synthesized through monomer MMA and BMA. Infrared spectrum was employed to characterize the as-synthesized copolymer. Results show that the main compositions of the copolymer are PMMA and PBMA. The binders were prepared by mixing the copolymer and the inorganic NH4H2PO4 with certain ratio. Binders were used to coat the Si3N4 and Al2O3 powders by spray drying. The coated powders were sintered successfully by SLS to make cubic part and rotor part.

A frontal polymerization method is used to produce highly porous polymer monoliths. The method is an approach to polymer synthesis that exploits the heat produced by the reaction itself. This heat triggers polymerization of neighboring monomer molecules, leading to a self-sustaining hot front, which propagates along the reacting vessel. Dissolved or microencapsulated foaming agents are decomposed only at the fronts, synchronizing the polymerization and the foaming. The ultimate pore structures appear to depend on the polymerization-front velocity and temperature. The resultant materials are porous, exhibiting tunable pore volume and a multimodal pore size distribution. No organic solvents or high-pressure equipment are used in the process, and no solvent residues are left in the resulting materials. Specifically, this route allows for the synthesis of large-scale samples with the additional advantages of high velocity, low energy cost, and the avoidance of multiple process steps. Substitution of hydrophilic acrylamide, N-isopropylacrylamide, with hydrophobic styrene and methyl methacrylate also leads to porous monolithic materials, suggesting that frontal polymerization represents a powerful and facile method for an exothermic polymerization reaction and the creation of porous polymers.

Superalloy powders, which have a small particle size and spherical shape, were prepared by a spark plasma discharge process. The electrical parameter, spark voltage, current and pulse duration have very important effects on the size distribution of produced superalloy powders. When current or pulse duration changed the mean size significantly changed.

The paper outlined here uses self-propagating high-temperature synthesis (SHS) or combustion synthesis that employs more efficient and effective high reaction and cooling rates to produce high quality, reproducible nitride fuels. The fundamental SHS processing parameters was determined to produce Mn-Si-C-N ceramic compounds in which Mn is a surrogate for Am. Because manganese nitride has a relatively low heat of formation the reaction can not be self-sustaining when Si was blended with Mn in the Si:Mn=0.25:1 ratio. The purity of MnSiN2 increases with an increase of the Mn content in Mn-Si-N system. Pure MnSiN2 can be synthesized when Si was blended with Mn in the Si:Mn = 0.5:1 ratio. Volume expansion and porosity decreases, so density, strength and hardness increase as increasing the Mn content in Mn-Si-N system. The powders and sintered cake of MnSiN2-Si3N4 or MnSiN2-Si3N4-SiC was produced by combustion synthesis. The sintered cake of MnSiN2-Si3N4-SiC is attacked by atmospheric moisture to fall to a powder.

Molybdenum has many prominent properties, such as high melting point, good thermal properties, and low erosion rate and so on, which make it promising candidate materials for plasma facing materials in the next fusion reactor. In this paper, Molybdenum coatings were deposited onto the oxygen-free copper substrates by atmospheric plasma spraying. The spraying parameters had been carefully selected. Different interlayers were induced between the substrate and the coating. SEM and XRD were used to investigate the photographs and compositions of these coatings. The micro-hardness and bonding strength were also tested. Thermal behaviors of the coatings were evaluated by thermal shock tests. The coatings with interlayers showed better resistance of thermal shock but lower bonding strength compared to coatings that without interlayers.

Machinable silicon nitride/ hexahedral boron nitride (Si3N4/h-BN) composites were in-situ synthesized in a nitrogen (N2) atmosphere by means of combustion synthesis gas-solid reaction with silicon (Si) powder and h-BN as raw materials. The effect of the volume fraction of h-BN on the machinable properties of Si3N4/BN composite was studied. The results show that Si powder was fully nitrified and no residual Si was found. Microstructures by a scanning electron microscopy (SEM) show Columnar crystals of β-Si3N4 are the main phase and acicular crystals of h-BN disperse β-Si3N4 intergranular. With the increasing of the volume content of h-BN, the machinability of the composite increases, but the bending strength of composite decreases firstly and then increases. The lowest bending strength is 84.96MPa at 25% volume fraction of h-BN.

The densification and phase transformation of high α-phase silicon nitride powder synthesized by SHS with a combination of Y2O3 and Al2O3 sintering additives were investigated. The densification process occurred rapidly from 1400 to 1500 °C and was nearly finished at 1500 °C. However, the α-β transformation of silicon nitride progressed rapidly from 1500 to 1600 °C, and completed at 1600 °C. The phase transformation of silicon nitride lagged behind the densification of Si3N4 ceramics. It showed that the solution and precipitation process did not play the main role in the densification of silicon nitride. The sufficient amount of liquid phase was crucial to complete the densification.

Silicon nitride was prepared by means of low-pressure preheating combustion synthesis in this paper. When N2 pressure is less than or equal to 2MPa, the lowest preheating temperature is about 653K, reactant could make silicon nitride by combustion synthesis. The additive of ammonium fluoride and ammonium chloride, as the reactive diluent, and Si react and make some useful intermediate products to α -Si3N4 after thermal decomposition. The reactive diluent content must be appropriate. At the same time, with the improvement of Si3N4, as the inert diluent, content in reactant, the adiabatic flame temperature of system would reduce, and combustion reaction rate of Si also drops, so it is propitious to make high level of α -Si3N4.

Sintering of the Self-Propagating High-Temperature Synthesis (SHS) of β-Si3N4 powder with 6.67 wt.% Y2O3 and 3.33 wt.% Al2O3 as sintering additives has been emphatically investigated using hot-press sintering process. The relative density of hot-pressed β-Si3N4 reached near to the full densification (99.43%) at 1700°C. The similar micrographs with self-reinforcing rod-like β-Si3N4 grains forming an interlocking structure were observed. The better mechanical properties of hot-pressed Si3N4, such as the hardness (16.73GPa), fracture toughness (5.72 MPa·m1/2) and bending strength (611.72MPa) values, were obtained at 1700°C. The results indicate that good sinter ability can be obtained with the cheaply SHS of silicon nitride powder for preparing silicon nitride materials, which will make the cost of silicon nitride materials lowered.

Tungsten has the highest melting point among all metal, which makes it withstand thermal shock and erosion in high temperature environments. In this study, Tungsten coatings were sprayed onto the oxygen-free copper substrates by plasma spraying using inert gases protection. XRD, SEM and EDS were used to identify the phases, morphologies and compositions of the coatings. Vickers micro-hardness and bonding strength of the tungsten coatings were also measured. The results revealed that the hardness distribution of the tungsten coatings was different along the thickness direction. The tungsten coating without any interlayer showed higher bonding strength than that of the other two coatings with NiCrAl and W/Cu interlayers, respectively.