The influence of Mo on the microstructure,bending strength and HV of Ti/Al 2O 3 composite was studied,and the influence mechanism was analyzed.The results indicate that after the addition of Mo,the composite organiz...The influence of Mo on the microstructure,bending strength and HV of Ti/Al 2O 3 composite was studied,and the influence mechanism was analyzed.The results indicate that after the addition of Mo,the composite organization is finer and phases distribution is better-proportioned which make the microstructure denser,the bending strength and HV of composite are also increased to a degree.But the bending strength increases first then decreases with the increasing of Mo content,so the appropriate Mo content for the Ti/Al 2O 3 composite is to be further confirmed.展开更多
High strength SiC whisker-reinforced Ti3SiC2 composites(SiCw/Ti3SiC2)with an improved thermal conductivity and mechanical properties were fabricated by spark plasma sintering.The bending strength of 10 wt%SiCw/Ti3SiC2...High strength SiC whisker-reinforced Ti3SiC2 composites(SiCw/Ti3SiC2)with an improved thermal conductivity and mechanical properties were fabricated by spark plasma sintering.The bending strength of 10 wt%SiCw/Ti3SiC2 was 635 MPa,which was approximately 50%higher than that of the monolithic Ti3SiC2(428 MPa).The Vickers hardness and thermal conductivity(k)also increased by 36%and 25%,respectively,from the monolithic Ti3SiC2 by the incorporation of 10 wt%SiCw.This remarkable improvement both in mechanical and thermal properties was attributed to the fine-grained uniform composite microstructure along with the effects of incorporated SiCw.The SiCw/Ti3SiC2 can be a feasible candidate for the in-core structural application in nuclear reactors due to the excellent mechanical and thermal properties.展开更多
The MAX phase Ti3SiC2 has broad application prospects in the field of rail transit,nuclear protective materials and electrode materials due to its excellent electrical conductivity,selflubricating properties and wear ...The MAX phase Ti3SiC2 has broad application prospects in the field of rail transit,nuclear protective materials and electrode materials due to its excellent electrical conductivity,selflubricating properties and wear resistance.Cu–Ti3SiC2 co-continuous composites have superior performance due to the continuous distribution of 3 D network structures.In this paper,the Cu/Ti3SiC2(Ti C/Si C)co-continuous composites are formed via vacuum infiltration process from Cu and Ti3SiC2 porous ceramics.The co-continuous composites have significantly improved the flexural strength and conductivity of Ti3SiC2 due to the addition of Cu,with the conductivity up to 5.73×10^5 S/m,twice as high as the Ti3SiC2 porous ceramics and five times higher than graphite.The reaction between ingredients leads to an increase in the friction coefficient,while the hard reaction products(Ti Cx,Si C)lower the overall wear rate(1×10^–3 mm^3/(N·m)).Excellent electrical conductivity and wear resistance make co-continuous composites more advantageous in areas such as rail transit.展开更多
Ti3SiC2/SiC composites were fabricated by reactive hot pressing method. Effects of hot pressing temperature, the content and particle size of SiC on phase composition, densification, mechanical properties and behavior...Ti3SiC2/SiC composites were fabricated by reactive hot pressing method. Effects of hot pressing temperature, the content and particle size of SiC on phase composition, densification, mechanical properties and behavior of stress-strain of the composites were investigated. The results showed that ： （ 1 ） Hot-pressing temperature influenced the phase composition of Ti3SiC2/SiC composites. The flexural strength and fracture toughness of composites increased with hot pressing temperature. （2） It became more difficult for the composites to densify when the content of SiC in composites increased. It need be sintered at higher temperature to get denser composite. The flexural strength and fracture toughness of composites increased when the content of SiC added in composites increased. However, when the content of SiC reached 50 wt%, the flexural strength and fracture toughness of composites decreased due to high content of pore in composites. （3） When the content of SiC was same, Ti3SiC2/SiC composites were denser while the particle size of SiC added in composites is 12. 8 μm compared with the composites that the particle size of SiC added is 3 μm. The flexural strength and fracture toughness of composites increased with the increase of particle size of SiC added in composites. （4） Ti3SiC2/SiC composites were non-brittle fracture at room temperature.展开更多
In this article, a new type of Cu-Ti3SiC2 composite powder prepared using the electroless plating technique was introduced. The initial Ti3SiC2 particles are 11 μm in diameter on an average. The Cu plating was carrie...In this article, a new type of Cu-Ti3SiC2 composite powder prepared using the electroless plating technique was introduced. The initial Ti3SiC2 particles are 11 μm in diameter on an average. The Cu plating was carried out at middle temperature （62-65℃） with the application of ultrasonic agitation. The copper deposition rate was determined by measuring the weight gain of the powder after plating. It has been found that the pretreatment of Ti3SiC2 powder is very important to obtain copper nanoparticles on the surface of Ti3SiC2 The optimum procedure before plating aimed to add activated sites and the adjustment of the traditional composition of the electroless copper plating bath could decelerate the copper deposition rate to 0.8 gm/h. X-ray diffraction （XRD） indicates that the chemical composition of the plating layer is copper. SEM images show that the surface of the Ti3SiC2 particles is successfully coated with continuous copper layer. The wetting property between the copper matrix and Ti3SiC2 can be improved so as to increase the interfacial strength.展开更多
ZA22/Al2O3 composites were prepared by means of squeeze casting process. The effects of Ce on the ultimate tensile strength (UTS), impact toughness, and hardness of the composites were studied. The results show that b...ZA22/Al2O3 composites were prepared by means of squeeze casting process. The effects of Ce on the ultimate tensile strength (UTS), impact toughness, and hardness of the composites were studied. The results show that both the UTS and the hardness are improved and the impact toughness is decreased with the increase of the volume fraction of fibers (Vf). After Ce is added ,UTS (Vf>15%) and the hardness are improved at room temperature because of the modification of Ce, but the impact toughness and UTS at elevated temperature are lowered.The filtered action of the fiber preform results in that the influence of the amount of Ce added from 0. 1 wt% to 0. 5 wt% on the mechanical properties of the composites can be ignored.展开更多
In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent ...In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent performance in improving the material properties. While no attempts have been made to add SiC whiskers and SiC nanoparticles together into the ceramic matrix and the synergistically toughening effects of them have not been studied. An Al2O3-SiCw-SiC np advanced ceramic cutting tool material is fabricated by adding both one-dimensional SiC whiskers and zero-dimensional SiC nanoparticles into the Al2O3 matrix with an effective dispersing and mixing process. The composites with 25 vol% SiC whiskers and 25 vol% SiC nanoparticles alone are also investegated for comparison purposes. Results show that the Al2O3-SiCw-SiCnp composite with both 20 vo1% SiC whiskers and 5 vol% SiC nanoparticles additives have much improved mechanical properties. The flexural strength of Al2O3-SiCw-SiCnp is 730＋ 95 MPa and fracture toughness is 5.6 ± 0.6 MPa.m1/2. The toughening and strengthening mechanisms of SiC whiskers and nanoparticles are studied when they are added either individually or in combination. It is indicated that when SiC whiskers and nanoparticles are added together, the grains are further refined and homogenized, so that the microstructure and fracture mode ratio is modified. The SiC nanoparticles are found helpful to enhance the toughening effects of the SiC whiskers. The proposed research helps to enrich the types of ceramic cutting tool and is benefit to expand the application range of ceramic cutting tool.展开更多
Al_(2)O_(3)/SiC composite ceramics were prepared fromα-Al_(2)O_(3) and SiC by a pressureless sinter method in this study.The effect of SiC contents on the mechanic properties,phase compositions and microstructure is ...Al_(2)O_(3)/SiC composite ceramics were prepared fromα-Al_(2)O_(3) and SiC by a pressureless sinter method in this study.The effect of SiC contents on the mechanic properties,phase compositions and microstructure is studied.Experimental results show that the vickers hardness,wear resistance and thermal conductivity of the samples increase with the increase in the SiC content,and the hardness of the sample reaches 16.22 GPa,and thermal conductivity of the sample reaches 25.41 W/(m.K)at room temperature when the SiC content is 20 wt%(B5)and the sintering temperature is at 1640℃.Higher hardness means higher scour resistance,and it indicates that the B5 material is expected to be used for the solar heat absorber of third generation solar thermal generation.The results indicate the mechanism of improving mechanical properties of Al_(2)O_(3)/SiC composite ceramics:SiC plays a role in grain refinement that the grain of SiC inhibits the grain growth of Al_(2)O_(3),while the addition of SiC changes the fracture mode from the intergranular to the intergranular-transgranular.展开更多
A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary...A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary phase including SrxCa1-xTiO3(0≤x≤1)solid solution and TiO2 co-exist in composite and form a stable composite system when the(CaxSr1-x)(0≤x≤1)substitutes for Zn of Li2ZnTi3O8 ceramic.As x is increased from 0 to 1,the relative permittivity(εr)increases from 26.65 to 27.12,and the quality factor(Q×f)increases from 63300 to 66600 GHz.With the increased of x,the temperature coefficient of resonant frequency(τf)increases from 0.27 to 8.23 ppm/℃,and then decreases to 3.51 ppm/℃.On the whole,the Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics show excellent comprehensive properties of middleεr=25-27,higher Q×f≥60000 GHz andτf≤±8.5 ppm/℃.展开更多
The composition, microstructures and properties of SiC /Al-2O-3/Al-Si composites formed by reactive penetration of the molten aluminum into the preforms of SiO-2 and SiC were investigated. The composition of the compo...The composition, microstructures and properties of SiC /Al-2O-3/Al-Si composites formed by reactive penetration of the molten aluminum into the preforms of SiO-2 and SiC were investigated. The composition of the composites was measured by X-ray diffraction (XRD). The microstructures of the composites were also measured by scanning electron microscopy (SEM) and optical microscopy. In addition, the factors affecting the properties of the composites were discussed.The experiments show that the mechanical properties of the composites depend on their relative densities and the sizes of the fillers“SiC grains".The denser the SiC/Al-2O-3/Al-Si composites,the higher their bending strength.As the filler “SiC grains" become fine,the bending strength of the composites increases.展开更多
Ti/Al 2O 3 composite with improved mechanical properties was synthesized by th e spark plasma sintering. The effect of Nb on the microstructure of the composit e was analyzed by TEM, SEM and so on. The experimental ...Ti/Al 2O 3 composite with improved mechanical properties was synthesized by th e spark plasma sintering. The effect of Nb on the microstructure of the composit e was analyzed by TEM, SEM and so on. The experimental results indicate that the bending strength, fracture toughness, micro-hardness and relative density of t he composite are 897.29MPa, 17.38MPa·m 1/2, 17.13GPa and 99.24% respec tively when adding 1.5vol%Nb. The bending strength is improved by reason of form ing dislocation ring and transfering fracture mode from intergranular to mixture fracture of intergranular and transgranular. The crack propagating is mainly th e deflection bridging. It indicates a reduction of crack driving force and an in crease in crack growth resistance,which results in toughness enhanced.展开更多
High-performance yttrium oxide-phenolic resin(Y_(2)O_(3)-PF)alternating coating was prepared on epoxy resin-based composite material using supersonic plasma spraying and dual-channel powder feeding technique.Y_(2)O_(3...High-performance yttrium oxide-phenolic resin(Y_(2)O_(3)-PF)alternating coating was prepared on epoxy resin-based composite material using supersonic plasma spraying and dual-channel powder feeding technique.Y_(2)O_(3)-coated PF(Y_(2)O_(3)/PF)powder was firstly sprayed onto the substrate,forming a transition layer,and then the spherical Y_(2)O_(3) powder and Y_(2)O_(3)/PF powder were alternately deposited to form the composite alternating coating.Results show that the alternating coating is mainly composed of deposited Y_(2)O_(3)/PF powder.The bonding strength between coating and substrate is as high as 26.48 MPa with the single-test maximum bonding strength of 28.10 MPa,and shear strength reaches 24.30 MPa.Additionally,the heat transfer effect caused by external Y_(2)O_(3) particles gradually softens and even melts PF,thus effectively avoiding the damage of high temperature to molecular structure and thereby promoting the crosslinking and curing effects of resin during the deposition process.In the meantime,the unmelted Y_(2)O_(3) powder results in the shot peening effect,which washes out and eliminates the powder particles with inferior deposition effect,ultimately improving the physical and chemical properties of the alternating coating.展开更多
This article provides a review of current research activities that concentrate on Ti3SiC2. We begin with an overview of the crystal and electronic structures, which are the basis to understand this material. Following...This article provides a review of current research activities that concentrate on Ti3SiC2. We begin with an overview of the crystal and electronic structures, which are the basis to understand this material. Followings are the synthetic strategies that have been exploited to achieve, and the formation mechanism of Ti3SiC2. Then we devote much attentions to the mechanical properties and oxidation/hot corrosion behaviors of Ti3SiC2 as well as some advances achieved recently. At the end of this paper, we elaborate on some new discoveries in the Ti3SiC2 system, and also give a brief discussion focused on the ＂microstructure -property＂ relationship.展开更多
文摘The influence of Mo on the microstructure,bending strength and HV of Ti/Al 2O 3 composite was studied,and the influence mechanism was analyzed.The results indicate that after the addition of Mo,the composite organization is finer and phases distribution is better-proportioned which make the microstructure denser,the bending strength and HV of composite are also increased to a degree.But the bending strength increases first then decreases with the increasing of Mo content,so the appropriate Mo content for the Ti/Al 2O 3 composite is to be further confirmed.
基金This study was supported by the National Natural Science Foundation of China(Grant Nos.11975296 and 51811540402)the Natural Science Foundation of Ningbo City(Grant No.2018A610001)the Korea Ministry of Education(NRF-2018K2A9A2A06018203).
文摘High strength SiC whisker-reinforced Ti3SiC2 composites(SiCw/Ti3SiC2)with an improved thermal conductivity and mechanical properties were fabricated by spark plasma sintering.The bending strength of 10 wt%SiCw/Ti3SiC2 was 635 MPa,which was approximately 50%higher than that of the monolithic Ti3SiC2(428 MPa).The Vickers hardness and thermal conductivity(k)also increased by 36%and 25%,respectively,from the monolithic Ti3SiC2 by the incorporation of 10 wt%SiCw.This remarkable improvement both in mechanical and thermal properties was attributed to the fine-grained uniform composite microstructure along with the effects of incorporated SiCw.The SiCw/Ti3SiC2 can be a feasible candidate for the in-core structural application in nuclear reactors due to the excellent mechanical and thermal properties.
文摘The MAX phase Ti3SiC2 has broad application prospects in the field of rail transit,nuclear protective materials and electrode materials due to its excellent electrical conductivity,selflubricating properties and wear resistance.Cu–Ti3SiC2 co-continuous composites have superior performance due to the continuous distribution of 3 D network structures.In this paper,the Cu/Ti3SiC2(Ti C/Si C)co-continuous composites are formed via vacuum infiltration process from Cu and Ti3SiC2 porous ceramics.The co-continuous composites have significantly improved the flexural strength and conductivity of Ti3SiC2 due to the addition of Cu,with the conductivity up to 5.73×10^5 S/m,twice as high as the Ti3SiC2 porous ceramics and five times higher than graphite.The reaction between ingredients leads to an increase in the friction coefficient,while the hard reaction products(Ti Cx,Si C)lower the overall wear rate(1×10^–3 mm^3/(N·m)).Excellent electrical conductivity and wear resistance make co-continuous composites more advantageous in areas such as rail transit.
文摘Ti3SiC2/SiC composites were fabricated by reactive hot pressing method. Effects of hot pressing temperature, the content and particle size of SiC on phase composition, densification, mechanical properties and behavior of stress-strain of the composites were investigated. The results showed that ： （ 1 ） Hot-pressing temperature influenced the phase composition of Ti3SiC2/SiC composites. The flexural strength and fracture toughness of composites increased with hot pressing temperature. （2） It became more difficult for the composites to densify when the content of SiC in composites increased. It need be sintered at higher temperature to get denser composite. The flexural strength and fracture toughness of composites increased when the content of SiC added in composites increased. However, when the content of SiC reached 50 wt%, the flexural strength and fracture toughness of composites decreased due to high content of pore in composites. （3） When the content of SiC was same, Ti3SiC2/SiC composites were denser while the particle size of SiC added in composites is 12. 8 μm compared with the composites that the particle size of SiC added is 3 μm. The flexural strength and fracture toughness of composites increased with the increase of particle size of SiC added in composites. （4） Ti3SiC2/SiC composites were non-brittle fracture at room temperature.
文摘In this article, a new type of Cu-Ti3SiC2 composite powder prepared using the electroless plating technique was introduced. The initial Ti3SiC2 particles are 11 μm in diameter on an average. The Cu plating was carried out at middle temperature （62-65℃） with the application of ultrasonic agitation. The copper deposition rate was determined by measuring the weight gain of the powder after plating. It has been found that the pretreatment of Ti3SiC2 powder is very important to obtain copper nanoparticles on the surface of Ti3SiC2 The optimum procedure before plating aimed to add activated sites and the adjustment of the traditional composition of the electroless copper plating bath could decelerate the copper deposition rate to 0.8 gm/h. X-ray diffraction （XRD） indicates that the chemical composition of the plating layer is copper. SEM images show that the surface of the Ti3SiC2 particles is successfully coated with continuous copper layer. The wetting property between the copper matrix and Ti3SiC2 can be improved so as to increase the interfacial strength.
文摘ZA22/Al2O3 composites were prepared by means of squeeze casting process. The effects of Ce on the ultimate tensile strength (UTS), impact toughness, and hardness of the composites were studied. The results show that both the UTS and the hardness are improved and the impact toughness is decreased with the increase of the volume fraction of fibers (Vf). After Ce is added ,UTS (Vf>15%) and the hardness are improved at room temperature because of the modification of Ce, but the impact toughness and UTS at elevated temperature are lowered.The filtered action of the fiber preform results in that the influence of the amount of Ce added from 0. 1 wt% to 0. 5 wt% on the mechanical properties of the composites can be ignored.
基金Supported by National Natural Science Foundation of China(Grant No.51175305)
文摘In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent performance in improving the material properties. While no attempts have been made to add SiC whiskers and SiC nanoparticles together into the ceramic matrix and the synergistically toughening effects of them have not been studied. An Al2O3-SiCw-SiC np advanced ceramic cutting tool material is fabricated by adding both one-dimensional SiC whiskers and zero-dimensional SiC nanoparticles into the Al2O3 matrix with an effective dispersing and mixing process. The composites with 25 vol% SiC whiskers and 25 vol% SiC nanoparticles alone are also investegated for comparison purposes. Results show that the Al2O3-SiCw-SiCnp composite with both 20 vo1% SiC whiskers and 5 vol% SiC nanoparticles additives have much improved mechanical properties. The flexural strength of Al2O3-SiCw-SiCnp is 730＋ 95 MPa and fracture toughness is 5.6 ± 0.6 MPa.m1/2. The toughening and strengthening mechanisms of SiC whiskers and nanoparticles are studied when they are added either individually or in combination. It is indicated that when SiC whiskers and nanoparticles are added together, the grains are further refined and homogenized, so that the microstructure and fracture mode ratio is modified. The SiC nanoparticles are found helpful to enhance the toughening effects of the SiC whiskers. The proposed research helps to enrich the types of ceramic cutting tool and is benefit to expand the application range of ceramic cutting tool.
基金Funded by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2018YFB1501002)。
文摘Al_(2)O_(3)/SiC composite ceramics were prepared fromα-Al_(2)O_(3) and SiC by a pressureless sinter method in this study.The effect of SiC contents on the mechanic properties,phase compositions and microstructure is studied.Experimental results show that the vickers hardness,wear resistance and thermal conductivity of the samples increase with the increase in the SiC content,and the hardness of the sample reaches 16.22 GPa,and thermal conductivity of the sample reaches 25.41 W/(m.K)at room temperature when the SiC content is 20 wt%(B5)and the sintering temperature is at 1640℃.Higher hardness means higher scour resistance,and it indicates that the B5 material is expected to be used for the solar heat absorber of third generation solar thermal generation.The results indicate the mechanism of improving mechanical properties of Al_(2)O_(3)/SiC composite ceramics:SiC plays a role in grain refinement that the grain of SiC inhibits the grain growth of Al_(2)O_(3),while the addition of SiC changes the fracture mode from the intergranular to the intergranular-transgranular.
基金Funded by the Open Project Program of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(No.KLIFMD201606)the Open Fund of National Innovation Platform(No.2017YJ163)+1 种基金the National Natural Science Foundation of China(Nos.51502220,51521001,and 51672197)the Open Foundation of Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics(Wuhan University of Technology)(No.TAM201802)。
文摘A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary phase including SrxCa1-xTiO3(0≤x≤1)solid solution and TiO2 co-exist in composite and form a stable composite system when the(CaxSr1-x)(0≤x≤1)substitutes for Zn of Li2ZnTi3O8 ceramic.As x is increased from 0 to 1,the relative permittivity(εr)increases from 26.65 to 27.12,and the quality factor(Q×f)increases from 63300 to 66600 GHz.With the increased of x,the temperature coefficient of resonant frequency(τf)increases from 0.27 to 8.23 ppm/℃,and then decreases to 3.51 ppm/℃.On the whole,the Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics show excellent comprehensive properties of middleεr=25-27,higher Q×f≥60000 GHz andτf≤±8.5 ppm/℃.
文摘The composition, microstructures and properties of SiC /Al-2O-3/Al-Si composites formed by reactive penetration of the molten aluminum into the preforms of SiO-2 and SiC were investigated. The composition of the composites was measured by X-ray diffraction (XRD). The microstructures of the composites were also measured by scanning electron microscopy (SEM) and optical microscopy. In addition, the factors affecting the properties of the composites were discussed.The experiments show that the mechanical properties of the composites depend on their relative densities and the sizes of the fillers“SiC grains".The denser the SiC/Al-2O-3/Al-Si composites,the higher their bending strength.As the filler “SiC grains" become fine,the bending strength of the composites increases.
基金Funded by the National Natural Science Foundation of China (No. 50232020) and the Natural Science Foundation of Shandong Province(No.2002F21)
文摘Ti/Al 2O 3 composite with improved mechanical properties was synthesized by th e spark plasma sintering. The effect of Nb on the microstructure of the composit e was analyzed by TEM, SEM and so on. The experimental results indicate that the bending strength, fracture toughness, micro-hardness and relative density of t he composite are 897.29MPa, 17.38MPa·m 1/2, 17.13GPa and 99.24% respec tively when adding 1.5vol%Nb. The bending strength is improved by reason of form ing dislocation ring and transfering fracture mode from intergranular to mixture fracture of intergranular and transgranular. The crack propagating is mainly th e deflection bridging. It indicates a reduction of crack driving force and an in crease in crack growth resistance,which results in toughness enhanced.
基金National Natural Science Foundation of China(52130509,52275211,52075542)Supported by 145 Project+1 种基金Science and Technology New Star Project of Shaanxi Innovation Capability Support Program(2021KJXX-38)China Postdoctoral Science Foundation(2021M693883)。
文摘High-performance yttrium oxide-phenolic resin(Y_(2)O_(3)-PF)alternating coating was prepared on epoxy resin-based composite material using supersonic plasma spraying and dual-channel powder feeding technique.Y_(2)O_(3)-coated PF(Y_(2)O_(3)/PF)powder was firstly sprayed onto the substrate,forming a transition layer,and then the spherical Y_(2)O_(3) powder and Y_(2)O_(3)/PF powder were alternately deposited to form the composite alternating coating.Results show that the alternating coating is mainly composed of deposited Y_(2)O_(3)/PF powder.The bonding strength between coating and substrate is as high as 26.48 MPa with the single-test maximum bonding strength of 28.10 MPa,and shear strength reaches 24.30 MPa.Additionally,the heat transfer effect caused by external Y_(2)O_(3) particles gradually softens and even melts PF,thus effectively avoiding the damage of high temperature to molecular structure and thereby promoting the crosslinking and curing effects of resin during the deposition process.In the meantime,the unmelted Y_(2)O_(3) powder results in the shot peening effect,which washes out and eliminates the powder particles with inferior deposition effect,ultimately improving the physical and chemical properties of the alternating coating.
基金supported by the National Outstanding Young Scientist Foundation for Y.C. Zhou under Grant No. 59925208the National Natural Science Foundation of China under Grants No. 50232040, No. 50302011 and No. 90403027"863" Project,and High-Tech Bureau of the Chinese Academy of Sciences
文摘This article provides a review of current research activities that concentrate on Ti3SiC2. We begin with an overview of the crystal and electronic structures, which are the basis to understand this material. Followings are the synthetic strategies that have been exploited to achieve, and the formation mechanism of Ti3SiC2. Then we devote much attentions to the mechanical properties and oxidation/hot corrosion behaviors of Ti3SiC2 as well as some advances achieved recently. At the end of this paper, we elaborate on some new discoveries in the Ti3SiC2 system, and also give a brief discussion focused on the ＂microstructure -property＂ relationship.
