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In order to improve the wear resistance of aluminum matrix composites and reduce the cost at the same time, the Al2O3/Al composite powder was prepared by hydrothermal method in this experiment, and the material properties of the Al2O3/Al metal matrix composite powder material were studied. It can be seen from the results that the encapsulation degree of Al2O3/Al-based composite powder material first increases and then decreases with the increase of ammonia concentration, and first increases and then decreases with the increase of PH value. The optimal molar ratio of salt and alkali is 1:1. Through the optimization of process parameters, the ratio of aluminum nitrate and ammonia water is obtained as: 1:1, the slurry stirring speed is 1500r/min, the stirring time is 10min, and the heating temperature is 200°C, the obtained composite powder is relatively uniform, has a larger specific surface area, and has better powder properties.

On the one hand, cermet has the advantages of metal materials, and on the other hand, it maintains the excellent properties of ceramic materials, and is a very important new engineering material. In this paper, the alumina/aluminum cermet material composite powder was prepared by ball milling, and its densification properties were characterized and studied to provide reference for the preparation of high-performance cermet materials. When the ball milling time is more than 6h, the distribution of alumina particles around the aluminum powder is relatively uniform. The research shows that: with the extension of the ball milling time, the number of pinning of Al2O3 particles on the surface of the Al ball first increases and then decreases; The trend of decreasing; with the increase of ball-to-powder ratio, the distribution of Al2O3 particles on the surface of Al balls is more uniform. Considering its cost-effectiveness, it is more suitable to prepare pinned alumina/aluminum-ceramic composite powder under the conditions of ball milling speed of 360r/min, ball-to-material ratio of 2:1 and ball milling time of 12h. When the Al content gradually decreased, the density and hardness of the cermet material also decreased gradually. When the Al content gradually decreased, the density and hardness of the cermet material also decreased gradually. When Al accounts for 75% in the sample, the microstructure is dense and the hardness is higher. When the molding pressure is 20MPa, the unevenness of the surface of the material is greatly relieved, relatively flat, and the densification effect is better. When the sintering temperature is 800°C, the fired sample is very dense, and the particles have relatively high bonding strength, but a small amount of aluminum is precipitated on the surface of the sample, forming a silver-white spherical substance.

With the popularization of "sponge city" in the whole country, the use of permeable bricks is increasing every year. Although the raw materials required for the preparation of permeable bricks are widely sourced, there are few reports on the process of using refractory waste to prepare permeable bricks. It is the ball milling process of refractory waste. The effects of ball milling time, ball mill rotation speed, and ball-to-material ratio on the properties of refractory waste were mainly studied. Through the experimental results and analysis, the following conclusions can be drawn: with the increase of ball milling time, ball milling speed and ball-to-material ratio, the particle size of refractory waste powder gradually decreases. Through research, it is concluded that the optimal ball milling time is 4h, the ball milling speed is 100r/min, and the ball-to-material ratio is 2:1.

In this paper, the YAG powder is prepared by the co-precipitation method. In addition, the sintering aid to aid sintering and the high temperature foaming agent that becomes gas released during the heating process so that the sample has pores, the ball mill mixes the material, and the sample press is extruded. Box-type resistance furnace sintering. Through this process, porous ceramics can be made. Study the effect of sintering aid content, foaming agent type, sintering temperature on the properties of YAG porous materials. The analysis and discussion can lead to the following conclusions: as the content of sintering aid silica in the sample increases, the sintering temperature of the sample decreases. It is best when the ratio of sintering aid alumina to silica is 3:1. The moldability of the sample whose foaming agent is wood chips is worse than that of the sample whose foaming agent is fiber and carbon powder. The ratio of sintering aid alumina to silica is 3:1, and the sintering temperature of the sample with carbon powder as the blowing agent is best when the sintering temperature is 1400 °C.

Yttrium aluminum garnet is abbreviated as YAG, which has many excellent high temperature characteristics. YAG structural materials and functional materials are promising candidates. In this paper, YAG porous ceramic materials with different mechanical properties are prepared by adjusting the parameters of the sintering process to provide reference for the preparation of high-performance porous ceramics. From the experimental results, the following conclusions can be drawn: when the sintering temperature is 1450°C and the holding time is 2h, the YAG gradient porous ceramics have no deformation and shrinkage, have a regular good shape, and have good strength after sintering. The sintering rate was 8 °C/min and carbon emission temperature is 800°C, the structure of the YAG gradient porous material is good, the pores are uniform, and the strength of the sintered sample is high, The porosity is 25.7%, the compressive strength is 8.12MPa.

The effect of forming technology on the properties of quartz sand porous materials were researched with the low grade quartz sand along the Yangtze River via the pressureless sintering method in this paper, which lay technology foundation for researching new heat insulating materials. The wear of ball milling media is investigated through adjusting the ball milling parameter via the weigh methods. The results are shown that the porosity of quartz sand porous materials are decreased with increasing a forming pressure. The porosities of Φ30 and Φ50 materials are decreased with increasing a holding pressure time, however, the porosity decreasing rate of Φ30 is slower than that of Φ50. The porosity of Φ50 is higher than that of Φ30 under same forming conditions. Through optimized the forming conditions, the porosity of sintered Φ50 quartz matrix porous materials reaches 54.52% under the forming pressure for 5MPa and the holding pressure time for 5min.

At present, the commonly used cement has low tensile strength and low flexural strength, which is a fatal defect of cement materials. It is extremely urgent to conduct research on this shortcoming of cement. In addition, the steel industry steel mill produces a large amount of waste steel slag. The chemical composition of steel slag is similar to that of cement. This experiment makes full use of waste steel slag as raw material to prepare cement to improve the performance of cement materials. Using limestone, sandstone, shale, steel slag and river sand as the main raw materials, through the powder preparation, mixing, calcination, grinding, molding process and performance analysis of raw materials. After the calcination, the cement clinker in the form of a block becomes higher in hardness as the steel slag is incorporated. The higher the calcination temperature, the smaller the steel slag incorporation maximum. When the calcined at 1150 °C is mixed with 17.5% steel slag, a cement with better performance can be obtained.

Dye-sensitized solar cells have better development prospects than silicon cells, and their main structural composition of nanoporous semiconductor films is particularly important. It is the tin dioxide film, and the effect of preparing tin oxide film on dye-sensitized solar cells under different conditions is studied. In this paper, the SnO2 powder was prepared by hydrothermal method, and the experiment was studied by controlled variable method. The properties of the obtained tin dioxide powder were characterized by SEM and three-dimensional ultra-depth microscope and XRD. The XRD diffraction peak is shown as tetragonal phase rutile type SnO2, With the increase of the concentration of tin tetrachloride solution, the coarser the particle size of the tin oxide crystal in the film, the more complicated the surface morphology, so that the specific surface area of the film is larger. At 0.1 mol/L, the surface of the film is a porous structure in the form of a loose sheet is presented. After analyzing the surface microstructure and flatness of the tin dioxide film, it can be concluded that the effect of salt concentration on the specific surface area of the film is extremely large. When the salt concentration is higher or lower, the obtained two the surface of the tin oxide film is relatively flat and has poor performance. When the salt concentration is 0.1mol/L, the surface of the obtained film has a large undulation and a large specific surface area, and the ability to adsorb the dye molecules can be predicted to be the greatest, and the photoelectric conversion efficiency is optimal in the photocatalytic process.

In this paper, the effect of sintering temperature on the interfacial structure of the composite was investigated and three different formulation groups were used to compare the respective properties. To obtain a composite material with excellent interface, the law between reference number and performance is obtained. Through mixing, molding, sintering, sample preparation, scanning electron microscopic observation, energy spectrometer observation and analysis, the following conclusions can be drawn: As the temperature increases, the density and hardness increase. The sample melts at 1500 °C, and there is no specific data. When the temperature reaches 1450 °C, the density and hardness reach the highest. When the formulation is Fe:Al2O3:SiO2=18:1:1 and the temperature reaches 1450 °C, the properties of the sample materials are optimized. The density is as high as 95% and the hardness reaches 42.9HBW.

In this paper, the effect on the properties of alumina/aluminum cermet by changing the sintering temperature, and comparing the advantages and disadvantages of different characterization methods and their application range, it provides a reference for selecting the characterization technology suitable for alumina/aluminum composites.Through mixing, molding, sintering, sample preparation, scanning electron microscopic observation, energy spectrometer observation and analysis, the following conclusions can be drawn: the higher the vacuum sintering temperature, the more aluminum material is melted out of the body to form aluminum balls on the surface, and the green body The more severe the cracking. When the sample is sintered at a temperature of 600 °C, the density is the highest and the appearance is the best. When the molding pressure is 40 MPa and the sintering temperature is 700 °C, the microstructure of the sintered alumina/aluminum cermet is better. It can be seen from SEM and EDS analysis that the particles are continuously distributed and the larger one is metal Al, and the particles are discontinuously distributed and finer is Al2O3.

In this paper, the effect of raw materaisl on the properties of coated Al2O3/Al cermet materials were investigated, the raw materials were prepared via different methods, which provide a reference for obtaining higher performance cermet materials. Through mixing, molding, sintering, sample preparation, scanning electron microscopic observation, energy spectrometer observation and analysis, the following conclusions can be drawn, the density of the cermet material prepared by the mechanical ball milling method (83.5%) is higher than that of the cermet material prepared by the chemical precipitation method (92.8%). It is nearly 10% lower. The alumina particles prepared by the ball milling method are agglomerated, and a large amount of agglomeration occurs in the aluminum, and the composition is very uneven. For materials prepared by the precipitation method, the aluminum oxide is uniformly distributed in the aluminum. The ball-milling powder is used to prepare materials, most of the alumina is in the form of particles, and in the precipitation method. In the powder preparation sample, the thin layer of alumina which forms the same eggshell envelops the aluminum, and the aluminum has a certain liquid phase change. the surface hardness (824HV) of the cermet material prepared by the mechanical ball milling method is lower than the surface hardness (1005HV) of the cermet material prepared by the chemical precipitation method.

Nano-SnO2 is a relatively important semiconductor material. Its crystal structure is unique rutile type. It has the advantages of high conductivity, high transparency and stable chemical properties. It is widely used in gas sensing detectors and solar cells for photoelectric conversion. Applications. In this paper, SnO2 nanofilms with different crystal structures were prepared by changing the three process parameters of salt concentration, reaction time and hydrothermal temperature in hydrothermal method. The samples were tested by scanning electron microscopy (SEM) and three-dimensional ultra-depth microscopy analyzer. As the concentration of the reaction solution increases, the macroscopic thickness of the film gradually thickens, and the three-dimensional structure of the surface changes from flat to coarse to coarse peak. The peak between the peaks first increases and then decreases, and the surface microstructure is The conditions change are not obvious. Through the comprehensive comparison of film integrity and surface area, it is found that the concentration is 0.03mol/L, which is relatively better.

Both alumina and boron carbide have good hardness and strength, and are widely used in production and life, industrial manufacturing, and military defense. However, due to the insufficiency of research at this stage and the lack of technical means, it is difficult to prepare alumina-boron carbide composite powder with good coating and ultra high strength through large-scale batch production. Therefore, this experiment wants to obtain a relatively good performance of coated Al2O3/B4C cermet by hydrothermal method through different experimental parameter ratios. Through the experimental results and analysis, the following conclusions are obtained. The most suitable concentration of aluminum nitrate is 0.1 mol/l. The low concentration affects the formation of alumina particles. The concentration is too high and prone to agglomeration. Through the optimization of hydrothermal synthesis concentration, a composite of Al2O3/B4C composite with good nanoencapsulated structure was obtained. The composite powder was pure in composition and high in specific surface area, which lays a foundation for solving the low-temperature preparation of high-density boron carbide ceramics.

Dye-sensitized solar cells have better development prospects than silicon cells, and the main structural components of nanoporous semiconductor films are particularly important. In this experimental study, we used tin dioxide film and investigated the effect of preparing this film on dye-sensitized solar cells under different conditions. Furthermore, SnO2 powder was prepared through hydrothermal method, and an experiment was conducted through a controlled variable method. The properties of the obtained tin dioxide powder were characterized by SEM, 3D ultradepth microscopy, and XRD. An XRD peak is displayed as tetragonal-phase rutile-type SnO2, and the SEM indicates that the powder grain size is several nanometers. With the increase in reaction time, the film gradually became flat and uniform from only a small amount of powder coating. At the reaction time of 8 days, the integrity and flatness of the film were optimal, and the pore size was uniform. Moreover, the specific surface area was large. In summary, the reaction time of 8 days is suitable for membrane growth.

The construction industry continues to develop and the requirements for cement performance are getting higher and higher. At the same time, in the steel industry, the discharge of steel slag is also increasing. The effective reuse of steel slag has become a prominent problem in the steel industry. . Therefore, it is envisaged to use steel slag as a raw material for the cement production process to produce cement and to produce high-performance cement. The main raw materials of this experiment are steel slag, limestone, sandstone and shale. Through the cement preparation process, the cement is made, and then the cement is made into concrete to test its performance. This experiment mainly studies the sintering temperature and holding time variable. In the experimental test, the analysis and comparison were carried out in five aspects of the degree of macroscopic cracking, particle size, density, microstructure and composition. In the comparison experiment of sintering temperature, with the increase of temperature, the flexural and compressive properties of cement gradually increased. In this test, 1200 °C is the most suitable temperature for the performance of the cement. Through the experimental comparison of different holding time, it is known that with the prolonging of the holding time, the microstructure and actual performance of the cement are continuously enhanced. Comprehensive consideration: the ratio of steel slag in cement ratio is 10%, sintering temperature is 1200 °C, and heat preservation is 2h. The steel slag cement prepared under this condition has the strongest performance.

YAG materials have a number of unique properties, the application is very extensive. In order to improving the properties of YAG porous materials, the effect of forming processing on the properties of YAG porous ceramics is investigated. Through the results and analysis, the conclusions showed that the porosity of YAG porous ceramics gradually decreased with the molding pressure increases, and the compressive strength of YAG porous ceramics shows a rising trend. The size and number of pores in the microstructure are reduced with increasing the forming pressure, there are inherently many voids in the YAG porous ceramics body at low forming pressures. The porosity of YAG porous ceramic decreases with the increase of dwell time, however, the process of extending from 5 min to 10 min is much faster than the rate of descending from 10 min to 15 min. The size and number of pores in the microstructure are reduced with extending the holding pressure time, which also makes YAG porous ceramics pose the higher mechanical strength. Through the analysis of the results, when the forming pressure is 10MPa, the porosity of YAG porous ceramics is 41.11% and the compressive strength is 5.8MPa, the porosity and compressive strength of YAG porous ceramics is better.

The Al2O3/Al cermet composite powders were prepared via the ball milling method,which provide raw materials for preparing high performance cermet materials. The results show that the number of Al2O3 particles on the surface of Al particles increases first and then decreases with increasing the ball milling time and milling rotating speed. The number of Al2O3 particles on the surface of Al particles increases with increasing ball to powder mass ratio. The analysis of the ratio of performance to price shows that the better parameters for preparing the pinned Al2O3/Al cermet composite powders are as follows, the ball milling time 24h,the ball milling rotating speed 100 r/min and the ratio of ball to powder 1:2.

A high-performance quartz sand insulation brick was prepared by using low grade quartz sand under different sintering process conditions. The optimum sintering process conditions were obtained by analyzing the relationship between microstructure and sintering process. Through the compounding, pulping, forming, drying and sintering processes, and the performance test of the porous brick, the following conclusions can be drawn, the comprehensive performance in all aspects, the porosity is similar, the preferred high compressive strength conditions, in order to get a best The bonding point, brick body sintering temperature of 1150 °C, porosity of 74.56%, compressive strength of 2.1 MPa of porous brick, and the pores are smooth, more uniform distribution. With the prolonging of the holding time, the porosity of the porous brick is reduced, and the performance is 1h, the porosity is 77.22% and the compressive strength is 2.05 MPa. When the raw material ratio is 60% quartz sand, 30wt% kaolin, calcium carbonate 9.6wt%, foaming agent 0.4wt%, water ratio 0.9 holding time at 1h sintering at 1150°C can get better porosity and compressive strength of the insulation brick. The porous material was sintered at 1150 °C, the content of foaming agent was 0.2wt%, the ratio of water to material was 0.9, and the compressive pressure and porosity were the better.

YAG has many excellent features and therefore has a wide range of applications. Preparation and properties of YAG porous ceramics via the casting method is investigated. Through analysis and discussion, the following conclusions can be obtained. With the increase of the content of foaming agent, in the foaming process of the slurry, bubbles generated by the foaming agent and water are gradually increased, the more pores are left in the body after casting, and when the blowing agent is too much, excessive bubbles are generated, which can lead to a very low strength of the green body and can not be formed and operated later. As the ratio of water to material increases, the porosity of the porous material increases. This is because when the blowing agent is constant, the amount of water required for foaming is constant, and the amount of foam generated is also constant. When the content of foaming agent and the ratio of water to material is both 1, the porosity and compressive strength is better.

Zirconium diboride is widely applied because of some excellent performances. The oxidation kinetics of ZrB2-YAG-Al2O3 composite materials were researched, which helps to improve the performance of ultra-high-temperature composite materials. The results show the oxidation weight gain is decreased with increasing the content of YAG-Al2O3 and the molar ratio of Al2O3. The oxidation weight gain is increased with prolonging the oxidation time under 1300°Cæ, the oxidation weight gain ratio is decreased with prolonging the oxidation time. The effecting tendency of oxidation weight gain is not abvious with varying the contend of YAG-Al2O3 upon 1300°Cæ, however, the effecting tendency of oxidation weight gain is very abvious with varying the molar ratio of Al2O3.

The composite ZrB2 powder coated A12O3-Y2O3 prepared by co-precipitation method were densified via the spark plasma sintering (SPS) and then researched the oxidation resistance at high temperature. ZrB2 powder must have the better dispersibility during the coating processing for obtaining the better coating effect. Effect of dispersant on the dispersibility of ZrB2 powder in the liquid is researched in this paper, the results show ZrB2 powder have the better dispersibility as the dispersant for PMAA and the content for 2vol%, which lay foundation for synthsising the better coating effect coated A12O3-Y2O3-ZrB2 composite powder.

Cermet materials is a important new engineering materials with the advantages of ceramics and metal materials. The Al2O3/Al cermet materials is prepared via the powder metallurgy method, the effect of sintering technology on properties of Al2O3/Al cermet materials is researched in this paper, which lay the base for preparing the high performance cermet materials. The results are shown through the study, the denstity of cermet is increased with an increasing moliding pressure, the sample density is 2.084g/cm3 as the pressure for 40MPa and the sintering temperature at 600¡æ, the density is higher, that is to say it is highest performance, the distribution of aluminum and alumina is most uniform. When the sintering temperature is higher, howerver, the molding pressure is lower, the lower density of the sample is shown, the aluminum is easier to overflow the surface of the sample.

Zirconium diboride (ZrB2) ceramics with high melting point, high hardness, good electrical and thermal conductivity, good neutron control and other characteristics, can be widely used in high-temperature structural ceramics, composite materials, electrode materials. In order to improve ZrB2 difficult densification and high-temperature oxidation, the properties of coated Al (OH)3-Y(OH)3/ZrB2 composite powders prepared by co-precipitation method were investigated in this paper, The conclusions are shown that the effect of coated composite powders is getting worse with the accelerated titration rates. the coating effect will be worse with the increasing reaction time. When the concentration of mixed solution is lower, the coated effect is better. When the synthesis condition is that the titration rate of 10ml/min, and the reaction time was 1h, mixed solution ion concentration of Y3+=0.119mol/L and Al3+=0.231mol/L, the coated effect of composite powders is better.

Superfine alumina has various excellent performance, superfine aluminum often used in metallurgy, aerospace, microelectronics and medicine, so the study of alumina has become a hot research at home and abroad, superfine alumina powder the body needs are also increasing. In this paper, superfine alumina powder were prepared by hydrothermal method, and to study the preparation process. The results show that the fibrous alumina particles gradually becomes granular with the increase of pH of the reaction, pH value of 9 to get a uniform particle size distribution and an average size of small powder particles. As the increasing calcination temperature, the alumina particles gradually grow, the homogeneous superfine particulate alumina powders is obtained under calcination temperature at 950¡æ. The better preferred process is that alkali molar ratio of 1:3, a concentration of 0.3mol/L, the reaction temperature at 200°C, calcination temperature of 950°C.

Alumina ceramics with good mechanical and corrosion resistance, is one of the most widely used engineering ceramics. The aluminum has a high strength, high conductivity, high plasticity, etc. than aluminum ceramics used in more and more industries. In this paper, aluminum and alumina powder as raw material, mixing, forming, sintering and a series of processes for preparing the alumina/aluminum metallic ceramic materials, through performance testing and analysis can be found in the ratio of raw materials 50wt% Al, 50wt % Al2O3 relatively good moldability. After sintering, after measuring the density contrast is found better density in the pressing process pressure of 20MPa and holding pressure time for 20min. By comparing the sintering process, after the interface structure by scanning electron microscopy and found help improve density through the secondary sintering metallic ceramic materials.

Pore gradient material has obvious uneven, making the material porosity, pore size and strength changes with the thickness of the material exhibits a special distribution, pore gradient material is therefore in the chemical industry, environmental protection, metallurgy, food, biotechnology and other industries widely used, it is a very promising new material. In this paper, low-grade quartz sand as the main raw material, by adding auxiliary ingredients, using foam deposition method, the pore graded material were prepared. Through experimental results and analysis, the conclusions can be obtained, quartz pore gradient material body after sintering at 1300¡æ posing obvious gradient structure. When the ratio of water to 1.4 and 1.5, the sample can be observed that there is a clear gradient structure. Considering the combination of price, quality quartz pore gradient material should be water feed ratio of 1.4, the sintering temperature is 1300 ¡æ more appropriate, the porosity of prepared quartz graded materials was 32.45%.

Cermet while maintaining the excellent properties of ceramic materials, but also have the advantages of a metal material, is an important new engineering materials. In this paper, prepared by calcination of alumina - aluminum metal-ceramic composite material powder, and its characterization as a basis to provide raw materials for preparing high performance metal ceramic material. According to the research, with the calcination temperature is increased, the rate of change gradually increase the weight of aluminum. Calcined at a temperature of 600¡æ, the oxidation of aluminum surface the best. With the firing time increases, the rate of change in the weight of aluminum powder showed an increasing trend. When 8h, oxidation of aluminum surface better. Through this experiment, process optimization can be found in the calcination temperature was 600¡æ, calcination time is 8h, the best coating effect aluminum surface, coating evenly, clean interface, the reaction layer thickness of about 700nm, the prepared package type composite powders the best results.

The technology of quartz pore gradient ceramics were researched with the low grade quartz sand along the Yangtze River via the vacuum sintering method in this paper, which lay technology foundation for exploiting new heat insulating materials. The research results are shown as following, when the ratio of water to raw materials is 1, the shape and pore distribution of pore gradient ceramics is better. The porosity are first increased and then decreased with an increasing the sintering temperature. The suitable sintering temperature is decided at 1100°Cæ, the density is 1.343g/cm3, the porosity is 48.7%, the compressive strength is 7.071MPa, and the pore gradient structure is homogeneous transition zone.

Metal ceramics are a important new engineering materials with the advantages of ceramics and metal materials. The Al-Al2O3 metal ceramics were prepared via the powder metallurgy methods and characterized in this paper, which lay the base for preparing the high performance cermet materials. Through the results and analysis, the conclusions are shown that the relative density is increased with a increasing forming pressure, the electrical resistivity is decreased with a increasing forming pressure. The relative density is increased with a increasing sintering temperature under 700°C, the relative density decreases with a increasing sintering temperature above 700°C, the electrical resistivity is shown the opposite tendency. Through the optimizing the technological parameter, such as the sintering temperature at 700°C, the forming pressure under 20MPa, the Al content for 75wt%, Al-Al2O3 metal ceramics are successfully prepared with the high relative density and the low electrical resistivity, the relative density is 97.52%, and the electrical resistivity is 101.34Ω·m

The shell structure YAG composite powders with different volume fraction (15, 20 and 25vol%) micro h-BN have been prepared by co-precipitation process. The bulk composites were performed by pressure sintering at 1600°C under a pressure of 30MPa in vacuum. The mechanical properties (elastic modulus, hardness, and fracture toughness) and relative density of the composites were investigated detailedly. Furthermore, phase composition and microstructure of the composites were analyzed thoroughly by X-ray diffraction, scanning electron microscopy. Meanwhile, good machinability is maintained due to the low hardness of the second phase.

Alumina-zirconia (Al2O3-ZrO2) composite ceramics were prepared by means of cross spraying and hydrothermal method under atmospheric pressure with nanometer powders doped with ZrO2 as the raw material. Then, the prepared powders and ceramics were characterized by SEM, XRD and BET methods. The results showed that combining cross spraying with hydrothermal method under atmospheric pressure could improve the dispersity of the ZrO2 composite ceramics nanopowders, while adding Al2O3 accelerated the low temperature sintering for 3Y-ZrO2 and improved the bending strength, fracture toughness and density of ZrO2 composite ceramics. In addition, through optimization the bending strength and fracture toughnessof the obtained ceramic, were 1,150 MPa and 8.2 MPa∙m1/2 respectively.

YAG is an important advanced structural and functional material. The mechanism of controlling pore microstructure of YAG porous ceramics were investigated in this paper. Through the porosity and SEM result analyzing, the conclusions are shown as follows, the porosity and the pore size of YAG porous ceramics are decreased with increasing the sintering temperature, the pores of YAG porous ceramics show a regular and well-distributed structure as lower sintering temperature, the porosity of YAG porous ceramics is increased with increasing the foaming agent content, but the increasing tendency is few after adding content more 15wt%, when the foaming agent content is less than 15wt%, the big pore is more and the pore microstructure is better. So the sintering temperature at 1500°C for 1 hour and the foaming agent content for 15wt% are better controlling conditions for obtaining better porosity and pore microstructure.

ZrB2 has some excellent high-temperature performance. However, due to it is easily oxidized in the high-temperature air to impact high-temperature strength, which restricts its applied range. To decrease the oxidization and sintering temperature, and improve the strength of ZrB2 at high temperature, in this paper, the prepared composite powders is analyzed with XRD, SEM, EDS and TEM, which proves ZrB2@A12O3-Y2O3 core-shell composite powders are successfully synthesized by co-precipitation method, the synthesis mechanism of ZrB2@A12O3-Y2O3 core-shell composite powders is received through the results discussion.

The low grade quartz sands is the main raw material to prepare the unfired porous brick through adjusting the maitenance technology. The compressive strength of brick is higher with the maitenance temperature for 40¡æ. The compressive strength of brick is higher with the longer maitenance time. The high performance brick is prepared via the third technology, the pore of brick is more and uniform, it is bowl shape, that is close pore, which provide the reference for preparing the heat insulating materials. The compressive strength of brick is 1.9MPa, the density is 0.628 g/cm3.

ZrB2, YAG and Al2O3 are widely applied because of some excellent performances, but ZrB2 is easily oxidized in the high-temperature air. To make the ZrB2 ceramics obtain better oxidation resistance, high-density ZrB2-YAG-Al2O3 ceramics were prepared. The oxidation mechanism of ZrB2-YAG-Al2O3 ceramics is investigated. When YAG-ZrB2 ceramics are exposed to air at temperatures from 1100°C¡æ to 1600°C¡æ, the weight change rate of YAG-ZrB2 ceramics is fleetly increased, the reacted speed of ZrB2 and O to form B2O3 and ZrO2 is more faster. The quantity of melted B2O3 is increased and carried to the surface, B2O3 is reacted with Al2O3 to form Al18B4O33. Al18B4O33 is melted and coated on the surface of ceramics to form protection layer for the oxidation resistance of ceramics at high temperature, which shows the similar with the influence of reinforcing phase on the oxidation model of ZrB2 based multi-phase ceramics.

The study of dye-sensitized solar cells (DSCs) based on nanocrystalline films of high band gap semiconductors is a progressive field of research that is being carried out by scientists in a wide range of laboratories. To improve the conversion efficiency of the DSCs, the SnO2 nanorots photocurrent is prepared via the hydrothermal method, and characterized by XRD, FESEM, BET and Absorption spectrum. Though analysis the results, the conclusion is shown the pure SnO2 is preparation, the SnO2 nanocrystalline both shows the single phase that SnO2 from the sule solution to kalin solution. The prepared SnO2 nanocrystalline under pH=3 shows the particle-shape crystalline, the surface area of SnO2 nanocrystalline is 86.3412m2/g. The prepared SnO2 nanocrystalline under pH=7 shows the short rod-shape crystalline, the surface area of SnO2 nanocrystalline is 58.3408m2/g. The absorbance of SnO2 nanocrystalline shows the strong absorption in the ultraviolet ray range, the absorbance of synthesized SnO2 nanocrystalline under pH=11 shows the highest value.

ZrB2, YAG and Al2O3 are widely applied because of some excellent performances, but ZrB2 is easily oxidized in the high-temperature air. To make the ZrB2 ceramics obtain better oxidation resistance, high-density ZrB2-YAG-Al2O3 ceramics were prepared. The influences of coated composite powders on the densification and the oxidation resistance of ZrB2-YAG-Al2O3 ceramics were investigated. The 80wt%ZrB2-YAG-Al2O3 multiphase ceramic materials from different composite raw materials with the spark plasma sintering technique were successfully prepared. The densification of ZrB2-YAG-Al2O3 ceramics with Al2O3-Y2O3 composite powder coated is easier than that of ZrB2-YAG-Al2O3 ceramics with YAG-Al2O3 powder mixed. The reaction temperature is lower than the 1100¡æ for synthesizing YAG powders from Al2O3-Y2O3 composite powders. The weight gain are increased with increased the oxidation temperature. B2O3 is reacted with Al2O3 to form Al18B4O33, Al18B4O33 is melted and coated on the surface of ceramics to form a protective layer for the oxidation resistance of ceramics at high temperature. The oxidation weight gain of ZrB2-YAG-Al2O3 ceramic with Al2O3-Y2O3 composite powder coated is lower than that of ZrB2-YAG-Al2O3 ceramic with YAG-Al2O3 powder mixed.

Yttrium aluminium garnet (YAG) possesses many good properties, and usually uesd as sintering additives for silicon carbide ceramics. The YAG precursor solution was preformed by the coprecipitation process, then 8wt% prepared precursor solution was added and uesed as binder for samples' green bodies dry mould pressing. The dried pressed samples were directly sintered at 1850¡æ under vaccum atmosphere, and the precursor Al2O3-Y2O3 could be formed YAG during sintering process. The oxidation resistance property was performed at 1500¡æ in air. Bulk density and porosity were about 2.42g/cm3 and 24.98% respectively, and three-point bonding strength was up to 90MPa. Phase composition of sintered specimen was determined by X-ray diffraction and fracture morphology was detected by scanning electron microscope (SEM). The results showed that the as-fabricated porous SiC ceramics exhlibted excellent oxidation resistance abilities, its oxidation resistance improvement was benefited from silicon carbide particle coated with a compact YAG layer. The relationship between microstructure and properties was analyzed, and the finally formed phase composition was discussed.

The study of dye-sensitized solar cells (DSCs) based on nanocrystalline films of high band gap semiconductors is a progressive field of research that is being carried out by scientists in a wide range of laboratories. Of the many semiconductor materials utilized for conversion of solar energy into electricity, SnO2 is a high band gap semiconductor that has been used extensively. However, its efficiency is at a relatively lower level when compared to other semiconductor materials such as TiO2 working under similar circumstances. To improve the conversion efficiency of the DSCs, the SnO2 nanorots photocurrent is prepared via the hydrothermal method, and characterized by XRD, FESEM, BET and Absorption spectrum. Though analysis the results, SnO2 nanocrystalline were successfully synthesized using a hydrothermal method by certainly experimental parameters. The SnO2 nanocrystalline is the rod-shape with length for 100nm and diameter for 5nm as pH=11. the specific surface area is 86.3412m2/g, which lay base for reaching the high conversion efficiency of the DSCs.

Zirconium diboride is widely applied because of some excellent performances. The results show the A1(OH)3-Y(OH)3/ZrB2 composite powders is prepared by a co-precipitation method, the shell-core structure A12O3-Y2O3/ZrB2 composite powders is prepared by sintering A1(OH)3-Y(OH)3/ZrB2 composite powders. The coating and density ZrB2-YAG-Al2O3 multi-phase ceramics is sintered at 1700°C, 20MPa for 4min by using Al2O3-Y2O3-80wt%ZrB2 composite powders, the oxidation weight is increased with increasing the oxidation temperature, however, the oxidation weight is decreased with increasing the YAG-Al2O3 content. ZrB2 reacted with O2 to form B2O3, and B2O3 is reacted with Al2O3 to form Al18B4O33, which is melted and coated on the surface of ceramics to form a protective layer for the oxidation resistance of ceramics at high temperature.

ZrB2 belongs to a class of ceramics defined ultra-high-temperature ceramics with extremely high melting temperatures, but ZrB2 ceramics is difficultly sintered and easily oxidized. To make ZrB2 ceramics possess the high relative density and the better oxidation resistance. The effects of adding phase on the sintering and oxidation resistance mechanism of ZrB2 based high-temperature multi-phase ceramics were investigated. YAG and Al2O3 help for the densification of ZrB2 based ceramics. The oxidation layer thickness of sintered ceramics adding YAG or YAG-Al2O3 phase is thinner than that of sintered pure ZrB2 ceramics under the same oxidation condition, the oxidation layer thickness of sintered ceramics adding YAG-Al2O3 phase is thinner than that of sintered ceramics adding YAG phase, the oxidation layer thickness of sintered ceramics is decreased with an increased Al2O3 content.

ZrB2, YAG, and Al2O3 are widely applied because of some excellent performance qualities, but ZrB2 is easily oxidized in high-temperature air. To make the ZrB2 ceramics obtain better oxidation resistance, high-density ZrB2–YAG–Al2O3 ceramics were prepared. The oxidation behavior of ZrB2–YAG–Al2O3 ceramics was investigated. The weight gain of ceramics was increased with increasing oxidation temperature, and the weight gain of ceramics was reduced with increasing YAG–Al2O3 content and Al2O3 proportion, especially above 1500°C. The weight gain was increased with prolonged oxidation time, but the rate of weight gain was decreased gradually after 2 h, and the weight gain was reduced with increasing YAG–Al2O3 content and Al2O3 proportion. Increasing YAG–Al2O3 content and Al2O3 proportion may raise the oxidation resistance of ZrB2–YAG–Al2O3 ceramics. Through the above analysis, the oxidation resistance model of ZrB2–YAG–Al2O3 ceramics was constructed to fully comprehend the oxidation process and mechanism.

Zirconium diboride (ZrB2) is difficult to prepare as high-density ceramics, which limits its application. To obtain high-density ZrB2 ceramics for improving its high-temperature properties, ZrB 2 particles were coated with Al2O3—Y 2O3 particles to prepare 20%YAG—ZrB2 ceramics with SPS. The optimum sintering condition is a temperature of 1700°C, a pressure of 20 MPa, and a holding time of 4 min. The relative density of prepared 20%YAG—ZrB2 multi-phase ceramics is 97.2% under optimization sintering technology, which indicate that high density YAG—ZrB 2 multi-phase ceramics are successfully prepared.

ZrB2 belongs to a class of ceramics defined ultra-high-temperature ceramics (UHTCs) with extremely high melting temperatures, but ZrB2 ceramics are difficult for densification. To make high relative density and good high-temperature property ZrB2 ceramics, in this article, the effect of YAG content on the property of YAG–ZrB2 multiphase ceramics is investigated. The sintering shrinkage is increasing with the increasing of the YAG content from 10% to 40%. The relative density increases with the increase of the YAG content from 10% to 40%, but the rate of increasing relative density from 10% to 30% is higher than that of 40%. When the content of YAG is higher than 30%, fracture toughness increases a little. The YAG content is more, and the weight gain is less, which shows that the oxidation layer thickness is thinner.

Although ZrB2 has some excellent performances, it is difficult to prepare the high relative-density ZrB2 ceramics, which limits the application of ZrB2 materials. To obtain higher relative-density ZrB2 ceramics for increasing the good oxidation resistance, YAG/ZrB2 multiphase ceramics is prepared with the spark plasma sintering, the sintering mechanism of preparing YAG/ZrB2 multiphase ceramic materials is investigated. Al2O3 reacts with Y2O3 to form YAG above 700°C during the sintering process. YAG is filled and melted the space of ZrB2 particles to bind the ZrB2 particles during reaction and sintering process, which increases the density of YAG/ZrB2 multiphase ceramic materials. The YAG/ZrB2 multiphase ceramic materials was successfully prepared under sintering temperature of 1700°C, holding temperature time for 4 min, and sintering pressure of 20 MPa; the density is 5.63 g/cm3, the relative density is 99.78%.

To obtain the better ZrB2/Al(OH)3–Y(OH)3 core-shell composite particles, ZrB2 particles must be adequately dispersed during the coating process. In this article, the dispersibility of ZrB2 particles in the ZrB2 suspension is investigated via the sedimentation method. Through test and analysis, the dispersibility is rapidly increased with prolonging the ultrasonic dispersion time before 10 minutes. After 30 minutes, the sedimentation grads using ultrasonic dispersion basically reach the sedimentation balance, but the grads using mechanical agitating dispersion does not basically change after 5 minutes. The ultrasonic dispersion is one of more effective ways between ultrasonic and mechanical agitating dispersion, the dispersion time for 10 minutes is chosen in the dispersibility of ZrB2 particles via ultrasonic dispersion.

In order to decrease the oxidization and improve the strength of ZrB2 at high temperature, the surface of ZrB2 was coated with Al(OH)3 and Y(OH)3 to synthesize Al(OH)3-Y(OH)3-ZrB2 composite particles. Through TEM, EPMA and SEM analysis, when pH was about 9, Al(OH)3-Y(OH)3-ZrB2 composite particles were successfully synthesized by co-precipitation methods. The coating layer was about 25 nm, which has compaction and conformability. Dispersibility of coated ZrB2 with Al(OH)3 and Y(OH)3 particles were very good. Synthesis of Al(OH)3-Y(OH)3-ZrB2 composite powder will lay the foundation for preparing high-performance YAG/ZrB2 and Al2O3-YAG/ZrB2 multiphase ceramic materials.