Volume 34,Issue 1,2005 Table of Contents
2005, 34(1):1-6.
Abstract:
The crystallization of amorphous alloys predestinates the microstructure and magnetic properties of the melt spun nanocomposite rare earth permanent magnets. Obeying the nucleation regularity, the model of the crystallization of amorphous alloys,namely, continually and explosively nucleation and growth. is put forward. The main factors affecting it were analyzed, such as melt-spun speed, the addition of alloys and the annealing sequence with or without the applied magnetic field, Especially, the re-distribution of the alloys during crystallization. On the bases, the ideas to gain ideal grain structure were discussed, for example, refining the grains by decomposition of metastable phase.
The crystallization of amorphous alloys predestinates the microstructure and magnetic properties of the melt spun nanocomposite rare earth permanent magnets. Obeying the nucleation regularity, the model of the crystallization of amorphous alloys,namely, continually and explosively nucleation and growth. is put forward. The main factors affecting it were analyzed, such as melt-spun speed, the addition of alloys and the annealing sequence with or without the applied magnetic field, Especially, the re-distribution of the alloys during crystallization. On the bases, the ideas to gain ideal grain structure were discussed, for example, refining the grains by decomposition of metastable phase.
2005, 34(1):7-11.
Abstract:
The waste material of precious metals is an important secondary resource. How to increase the utilization of these waste materials and treat them innoxiously is an important problem, and have drawn a wide attention around the world. In this paper, the characterization, origination, pretreatment methods of waste materials of precious metals and the recovering technology of gold, silver, platinum and palladium from above waste materials have been reviewed. Several suggestions about innoxious treatment on the waste materials of precious metals have been proposed.
The waste material of precious metals is an important secondary resource. How to increase the utilization of these waste materials and treat them innoxiously is an important problem, and have drawn a wide attention around the world. In this paper, the characterization, origination, pretreatment methods of waste materials of precious metals and the recovering technology of gold, silver, platinum and palladium from above waste materials have been reviewed. Several suggestions about innoxious treatment on the waste materials of precious metals have been proposed.
2005, 34(1):12-15.
Abstract:
Thermoelectric materials used for the conversation between thermal energy and electric energy make it possible to manufacture no pollution, no mechanical moving and high effective equipments which can be used for generate electricity and refrigeration. with the increase of environment problems and energy consumption, thermoelectric materials have been drawing more and more attention. The R&D of various thermoelectric materials are introduced and reviewed.
Thermoelectric materials used for the conversation between thermal energy and electric energy make it possible to manufacture no pollution, no mechanical moving and high effective equipments which can be used for generate electricity and refrigeration. with the increase of environment problems and energy consumption, thermoelectric materials have been drawing more and more attention. The R&D of various thermoelectric materials are introduced and reviewed.
2005, 34(1):16-21.
Abstract:
分别以Miedema坐标、合金自扩散激活能ΔHs与形成焓ΔHf为参数坐标，将多元合金分解为若干相应的二元合金叠加，对有实验结果的128个二元和153个多元机械合金化(MA)非晶合金的形成规律进行了研究。结果：以上2种坐标中，分别可由一直线或曲线将非晶形成与非形成区分割，方程为：Miedema坐标，二元系，y=2．8600x 0．22；多元系，y=2．7900x 0．27，总区分率均为80％：ΔHs～ΔHf坐标，二元系，y=0．0005x^2 0．20x-23；多元系，y=0．0005x^ 0．21x-25，总区分率分别为85％和83％。合金包含过渡族金属、涵盖非过渡族金属及类金属，并扩展至多元系，同时与已有定性以及半定量结果进行了比较。
分别以Miedema坐标、合金自扩散激活能ΔHs与形成焓ΔHf为参数坐标，将多元合金分解为若干相应的二元合金叠加，对有实验结果的128个二元和153个多元机械合金化(MA)非晶合金的形成规律进行了研究。结果：以上2种坐标中，分别可由一直线或曲线将非晶形成与非形成区分割，方程为：Miedema坐标，二元系，y=2．8600x 0．22；多元系，y=2．7900x 0．27，总区分率均为80％：ΔHs～ΔHf坐标，二元系，y=0．0005x^2 0．20x-23；多元系，y=0．0005x^ 0．21x-25，总区分率分别为85％和83％。合金包含过渡族金属、涵盖非过渡族金属及类金属，并扩展至多元系，同时与已有定性以及半定量结果进行了比较。
2005, 34(1):22-27.
Abstract:
The effects of the binder composition, powder loading, thermal properties of feedstocks, and the injection molding parameters on the compact shape retention for metal injection molding 17-4PH stainless steel were investigated. HDPE is more effective as a second component of the wax-based binder to retain compact shape than EVA due to its higher pyrolytic temperature and higher heat of fusion. The compact distortion decreases with the increase of powder loading, molding pressure and molding temperature. There exists a best process condition, including powder loading, molding pressure and molding temperature. Under this process condition, the lowest percentage is there of distorted compacts.
The effects of the binder composition, powder loading, thermal properties of feedstocks, and the injection molding parameters on the compact shape retention for metal injection molding 17-4PH stainless steel were investigated. HDPE is more effective as a second component of the wax-based binder to retain compact shape than EVA due to its higher pyrolytic temperature and higher heat of fusion. The compact distortion decreases with the increase of powder loading, molding pressure and molding temperature. There exists a best process condition, including powder loading, molding pressure and molding temperature. Under this process condition, the lowest percentage is there of distorted compacts.
2005, 34(1):28-32.
Abstract:
The surfaces of Zr-Ti hydrogen storage alloys are modified with methods such as chemical plating of nickel or cobalt, mechanical mixture, ball grinding and so on. XRD shows that the alloy has the trend to form micro-crystals with the content of coating nickel increasing, and long grinding time leads to dispersion of diffraction peaks of alloys. When the discharge current density is 60mA.g-1, the initial capacity of the alloy electrode plated Ni 15wt% is 130 mAh.g-1 more than that of untreated alloy. The alloy is activated absolutely after 6 cycles ~8 cycles, and the max discharge capacity can reach 400 mAh.g-1. The discharge capacity of alloy electrode with 5% Co can be up to 390 mAh.g-1. Anti-discharge ability increases with the percentage of Ni plated. The activation behavior of hydrogen storage alloys is also improved by ball grinding, and the max discharge capacity can reach 450 mAh.g-1. Mechanical mixture can only increase initial capacity without any improvement of max discharge capacity.
The surfaces of Zr-Ti hydrogen storage alloys are modified with methods such as chemical plating of nickel or cobalt, mechanical mixture, ball grinding and so on. XRD shows that the alloy has the trend to form micro-crystals with the content of coating nickel increasing, and long grinding time leads to dispersion of diffraction peaks of alloys. When the discharge current density is 60mA.g-1, the initial capacity of the alloy electrode plated Ni 15wt% is 130 mAh.g-1 more than that of untreated alloy. The alloy is activated absolutely after 6 cycles ~8 cycles, and the max discharge capacity can reach 400 mAh.g-1. The discharge capacity of alloy electrode with 5% Co can be up to 390 mAh.g-1. Anti-discharge ability increases with the percentage of Ni plated. The activation behavior of hydrogen storage alloys is also improved by ball grinding, and the max discharge capacity can reach 450 mAh.g-1. Mechanical mixture can only increase initial capacity without any improvement of max discharge capacity.
7 Numerical Calculation of Fluid Viscosity in Hot Hydrostatic Extrusion of High Density Tungsten Alloy
2005, 34(1):33-36.
Abstract:
This paper analyzed the flow of working medium in extrusion by an athletic differential equation of viscous fluid and discussed the influence of the viscosity on Hot Hydrostatic Extrusion(HHE). Extrusion force of HHE can be minimized and the disfigurement of extrusion products can be avoided when the viscosity of the medium is proper. A mathematics formula for the viscosity of working medium is given important theoretic foundation for HHE.
This paper analyzed the flow of working medium in extrusion by an athletic differential equation of viscous fluid and discussed the influence of the viscosity on Hot Hydrostatic Extrusion(HHE). Extrusion force of HHE can be minimized and the disfigurement of extrusion products can be avoided when the viscosity of the medium is proper. A mathematics formula for the viscosity of working medium is given important theoretic foundation for HHE.
2005, 34(1):37-40.
Abstract:
利用有限元法，采用弹塑性理论对Al2O3陶瓷／Nb接头的应力场进行了数值模拟。得出了接头部位应力σx，σy和τxy的分布状态，研究发现在当接头界面结合良好时在界面附近的陶瓷侧的残余主应力(σ1)出现极大值，裂纹最有可能从此处开启，然后在残余主应力(σ2)的作用下向陶瓷内部延伸。
利用有限元法，采用弹塑性理论对Al2O3陶瓷／Nb接头的应力场进行了数值模拟。得出了接头部位应力σx，σy和τxy的分布状态，研究发现在当接头界面结合良好时在界面附近的陶瓷侧的残余主应力(σ1)出现极大值，裂纹最有可能从此处开启，然后在残余主应力(σ2)的作用下向陶瓷内部延伸。
2005, 34(1):41-45.
Abstract:
通过磁性测量和X-射线衍射研究了Gd2(Co，Al)17化合物的结构和磁晶各向异性。当x≤4时，样品具有菱方Th2znl7型结构，x=5时，具有六方CaCu5型结构。随着Al浓度增加，晶格常数和单胞体积单调增大，而居里温度和自发磁化强度近似线性地减小；在x≥l时，观察到Co亚点阵的磁晶各向异性变号，室温易磁化方向由易面转变为易轴，且易轴各向异性场和各向异性常数随Al原子浓度增加出现极大值；基于补偿温度(65K)下自由粉末颗粒的磁化曲线，导出了亚点阵间的分子场系数和Gd-co交换耦合常数，结果表明，Al原子对Gd-Co交换耦合作用的影响较小。根据Al原子在Co亚点阵4种晶位的择优占位，分析了磁晶各向异性的演变。
通过磁性测量和X-射线衍射研究了Gd2(Co，Al)17化合物的结构和磁晶各向异性。当x≤4时，样品具有菱方Th2znl7型结构，x=5时，具有六方CaCu5型结构。随着Al浓度增加，晶格常数和单胞体积单调增大，而居里温度和自发磁化强度近似线性地减小；在x≥l时，观察到Co亚点阵的磁晶各向异性变号，室温易磁化方向由易面转变为易轴，且易轴各向异性场和各向异性常数随Al原子浓度增加出现极大值；基于补偿温度(65K)下自由粉末颗粒的磁化曲线，导出了亚点阵间的分子场系数和Gd-co交换耦合常数，结果表明，Al原子对Gd-Co交换耦合作用的影响较小。根据Al原子在Co亚点阵4种晶位的择优占位，分析了磁晶各向异性的演变。
10 Computer Simulation of the Mechanism of Ordered Precipitates of Al-Li Alloy in External Energy Filed
2005, 34(1):46-50.
Abstract:
基于离散格点形式的微扩散方程(Langevin方程)和非平衡自由能函数，编制了引入原子间相互作用能变化的Al3Li(δ′)相沉淀原子层面计算机模拟程序。该程序包容亚稳区到失稳区的全部温度、成分范围，孕育期至粗化的全过程，可以处理与时间相关的过程问题。开展了不同原子间相互作用势下原子图像、序参数的计算机模拟，进而探讨了最近邻原子相互作用能(W1)对有序相沉淀的影响机制。探明过渡区合金先发生等成分有序化，后进行失稳分解；随W1的增大，有序相沉淀的孕育期缩短，单相有序畴数量增多，面积减小，合金达到最大有序化的时间早，所能达到的最大有序化程度大。W1值较大，会促进合金有序化和原子簇聚，阻碍无序相的形成。
基于离散格点形式的微扩散方程(Langevin方程)和非平衡自由能函数，编制了引入原子间相互作用能变化的Al3Li(δ′)相沉淀原子层面计算机模拟程序。该程序包容亚稳区到失稳区的全部温度、成分范围，孕育期至粗化的全过程，可以处理与时间相关的过程问题。开展了不同原子间相互作用势下原子图像、序参数的计算机模拟，进而探讨了最近邻原子相互作用能(W1)对有序相沉淀的影响机制。探明过渡区合金先发生等成分有序化，后进行失稳分解；随W1的增大，有序相沉淀的孕育期缩短，单相有序畴数量增多，面积减小，合金达到最大有序化的时间早，所能达到的最大有序化程度大。W1值较大，会促进合金有序化和原子簇聚，阻碍无序相的形成。
2005, 34(1):51-55.
Abstract:
通过热力学平衡相计算方法并采用相应的Ni基数据库，对1种新型高铬的Ni-Cr基GH648合金成分对平衡相析出的影响规律进行系统研究。结果认为GH648合金析出的主要平衡相为α-Cr，γ′相和M23C6碳化物(主要为Cr23C6)，并进一步计算了合金成分对这些相的析出行为及合金初熔点和终熔点的影响规律。计算结果表明，Cr含量主要影响α-Cr的析出量及开始析出温度，并影响合金的初熔点，对以Cr为主的M23C6的析出行为没有明显影响。C显著影响碳化物的析出量，而Al，Ti增加显著增加γ′相的析出量和开始析出温度。
通过热力学平衡相计算方法并采用相应的Ni基数据库，对1种新型高铬的Ni-Cr基GH648合金成分对平衡相析出的影响规律进行系统研究。结果认为GH648合金析出的主要平衡相为α-Cr，γ′相和M23C6碳化物(主要为Cr23C6)，并进一步计算了合金成分对这些相的析出行为及合金初熔点和终熔点的影响规律。计算结果表明，Cr含量主要影响α-Cr的析出量及开始析出温度，并影响合金的初熔点，对以Cr为主的M23C6的析出行为没有明显影响。C显著影响碳化物的析出量，而Al，Ti增加显著增加γ′相的析出量和开始析出温度。
2005, 34(1):56-59.
Abstract:
The structure of K2Ti6O13 nanowires has been investigated using both the Rietveld powder diffraction profile fitting technique and high resolution transmission electron microscopy (HRTEM) image simulations. the Rietiveld analysis show that the nanowires had a monoclinic structure of the space group C2/M. The good agreement between the experimental and simulated images confirms that the nanowires is indeed K2Ti6O13 nanowire. HRTEM conclusions agree with refinement results obtained from experimental XRD data. The nanowires grow out mainly along the [010] direction.
The structure of K2Ti6O13 nanowires has been investigated using both the Rietveld powder diffraction profile fitting technique and high resolution transmission electron microscopy (HRTEM) image simulations. the Rietiveld analysis show that the nanowires had a monoclinic structure of the space group C2/M. The good agreement between the experimental and simulated images confirms that the nanowires is indeed K2Ti6O13 nanowire. HRTEM conclusions agree with refinement results obtained from experimental XRD data. The nanowires grow out mainly along the [010] direction.
2005, 34(1):60-63.
Abstract:
弹性变形范围内,在采用三维有限元模型分析了颗粒增强Mg基复合材料(PRMMCs)中,颗粒的分布形态对材料微区力学状态的影响。结果表明,在保持颗粒长径比(2:1)和颗粒间距(d)不变的情况下,随着θ的变化,不存在颗粒断裂的危险,材料的主要失效方式为界面脱离和基体开裂。增强体相对夹角θ=15o时的结果优于其它情况,这更有利于充分发挥材料的性能。
弹性变形范围内,在采用三维有限元模型分析了颗粒增强Mg基复合材料(PRMMCs)中,颗粒的分布形态对材料微区力学状态的影响。结果表明,在保持颗粒长径比(2:1)和颗粒间距(d)不变的情况下,随着θ的变化,不存在颗粒断裂的危险,材料的主要失效方式为界面脱离和基体开裂。增强体相对夹角θ=15o时的结果优于其它情况,这更有利于充分发挥材料的性能。
2005, 34(1):64-68.
Abstract:
为了推进从俄罗斯引进的田湾VVER-1000型核电站用Zr-1Nb合金燃料包壳和端塞棒材的国产化进程，研究了焊接及随后的真空热处理对Z4-1Nb合金抗360℃，18．6MPa水和500℃，10.3MPa蒸汽腐蚀性能的影响。实验结果表明焊接严重恶化Zr-1Nb合金在2种介质中的腐蚀抗力，主要是因为焊区中出现了粗大的马氏体组织；随后的真空退火对腐蚀抗力的影响取决于退火温度和腐蚀实验温度。但即使在最佳温度退火也不能使焊接态的腐蚀抗力恢复到非焊接态的水平。
为了推进从俄罗斯引进的田湾VVER-1000型核电站用Zr-1Nb合金燃料包壳和端塞棒材的国产化进程，研究了焊接及随后的真空热处理对Z4-1Nb合金抗360℃，18．6MPa水和500℃，10.3MPa蒸汽腐蚀性能的影响。实验结果表明焊接严重恶化Zr-1Nb合金在2种介质中的腐蚀抗力，主要是因为焊区中出现了粗大的马氏体组织；随后的真空退火对腐蚀抗力的影响取决于退火温度和腐蚀实验温度。但即使在最佳温度退火也不能使焊接态的腐蚀抗力恢复到非焊接态的水平。
2005, 34(1):69-72.
Abstract:
通过等温压缩特性及微观组织演变研究，提出了有效的γ-TiAl基合金晶粒细化方法。研究发现，如果γ-TiAl合金锭具有一定的细晶组织便可以在(α2 γ)2相区完成等温变形而不产生裂纹。动态再结晶和静态球化数量的增加是提高γ-TiAl合金变形能力的主要原因。将等温变形的模拟锻件在不同相区进行热处理获得了具有细小尺寸的3种(全片层、近片层和双态)组织。
通过等温压缩特性及微观组织演变研究，提出了有效的γ-TiAl基合金晶粒细化方法。研究发现，如果γ-TiAl合金锭具有一定的细晶组织便可以在(α2 γ)2相区完成等温变形而不产生裂纹。动态再结晶和静态球化数量的增加是提高γ-TiAl合金变形能力的主要原因。将等温变形的模拟锻件在不同相区进行热处理获得了具有细小尺寸的3种(全片层、近片层和双态)组织。
2005, 34(1):73-76.
Abstract:
Hexagonal wurtzite GaN materials with nano-structure have been fabricated on Si (111) substrates via ammoniating ZnO/Ga2O3 films at different temperatures. ZnO layers and Ga2O3 films were deposited in turn on Si (111) substrates by radio frequency (r.f.) magnetron sputtering before the ammoniating process. The structure and composition of GaN crystal were studied by X-ray diffraction(XRD) and fourier transform infrared spectrophotometer(FTIR).The morphology of the samples was studied by scanning electron microscopy (SEM).Through the analyses of the measurement results , a conclusion can be drawn that hexagonal wurtzite GaN with nano structure was grown on Si (111) substrates with the assistance of the volatilization of ZnO, and the ammoniating temperature has a great effect on the fabrication of GaN nano materials with this method.
Hexagonal wurtzite GaN materials with nano-structure have been fabricated on Si (111) substrates via ammoniating ZnO/Ga2O3 films at different temperatures. ZnO layers and Ga2O3 films were deposited in turn on Si (111) substrates by radio frequency (r.f.) magnetron sputtering before the ammoniating process. The structure and composition of GaN crystal were studied by X-ray diffraction(XRD) and fourier transform infrared spectrophotometer(FTIR).The morphology of the samples was studied by scanning electron microscopy (SEM).Through the analyses of the measurement results , a conclusion can be drawn that hexagonal wurtzite GaN with nano structure was grown on Si (111) substrates with the assistance of the volatilization of ZnO, and the ammoniating temperature has a great effect on the fabrication of GaN nano materials with this method.
2005, 34(1):77-81.
Abstract:
研究了不同能量界面动态共混过程中的界面反应及其对沉积在GCr15和45钢基体的IBAD CrN薄膜结合强度的影响。用AFM和GDOES分析了不同能量共混界面的形貌和成分。用循环滚动接触法使薄膜在膜基最薄弱处产生剥落，用以分析界面反应产物，同时对膜基结合强度加以评价。用SEM，EDAX和XPS分析了滚动接触疲劳试验后的疲劳剥落区的形貌、成分及结构。结果表明40kV共混后的界面粗糙度高并出现了碳含量的升高，而20kv时界面碳含量和基体差不多。基体碳化物在离子轰击引起的热峰效应的作用下发生分解，而对基体和碳化物的选择溅射导致了碳含量的升高以及粗糙度的增加。分解后的碳以石墨态的形式存在。在滚动接触疲劳试验时循环载荷的作用下，界面处的石墨相当于孔洞引起应力集中。疲劳裂纹起始于界面石墨富集处表明它是引起结合强度差的主要原因。
研究了不同能量界面动态共混过程中的界面反应及其对沉积在GCr15和45钢基体的IBAD CrN薄膜结合强度的影响。用AFM和GDOES分析了不同能量共混界面的形貌和成分。用循环滚动接触法使薄膜在膜基最薄弱处产生剥落，用以分析界面反应产物，同时对膜基结合强度加以评价。用SEM，EDAX和XPS分析了滚动接触疲劳试验后的疲劳剥落区的形貌、成分及结构。结果表明40kV共混后的界面粗糙度高并出现了碳含量的升高，而20kv时界面碳含量和基体差不多。基体碳化物在离子轰击引起的热峰效应的作用下发生分解，而对基体和碳化物的选择溅射导致了碳含量的升高以及粗糙度的增加。分解后的碳以石墨态的形式存在。在滚动接触疲劳试验时循环载荷的作用下，界面处的石墨相当于孔洞引起应力集中。疲劳裂纹起始于界面石墨富集处表明它是引起结合强度差的主要原因。
2005, 34(1):82-85.
Abstract:
研究了放电等离子烧结(SPS)纳米WC-10%Co-0.8%VC硬质合金的致密化机理,并与真空烧结的制品显微组织及性能进行对比。SPS特殊的直流脉冲电压使烧结中蒸发-凝固、塑性流动、表面扩散等过程得到加强,使制品在低温下快速致密,有效抑制了晶粒的长大,如在1200℃烧结5min的制品平均晶粒尺寸<100nm。与真空烧结相比,SPS可以使制品在低温、短时间内获得高密度、高硬度,如1300℃烧结3min,制品相对密度达97.7%,HV30比相同烧结温度下真空烧结30min的相对密度92.8%的制品高近16.4%。SPS烧结温度降低至1200℃,虽然密度有所降低,但HV30和KIC分别提高了15.4%和12.2%。
研究了放电等离子烧结(SPS)纳米WC-10%Co-0.8%VC硬质合金的致密化机理,并与真空烧结的制品显微组织及性能进行对比。SPS特殊的直流脉冲电压使烧结中蒸发-凝固、塑性流动、表面扩散等过程得到加强,使制品在低温下快速致密,有效抑制了晶粒的长大,如在1200℃烧结5min的制品平均晶粒尺寸<100nm。与真空烧结相比,SPS可以使制品在低温、短时间内获得高密度、高硬度,如1300℃烧结3min,制品相对密度达97.7%,HV30比相同烧结温度下真空烧结30min的相对密度92.8%的制品高近16.4%。SPS烧结温度降低至1200℃,虽然密度有所降低,但HV30和KIC分别提高了15.4%和12.2%。
2005, 34(1):86-90.
Abstract:
选用了分散性能较差的4种商业氮化硅粉料，系统研究了表面水解及热氧化处理对氮化硅粉料表面特性及分散性能的影响，并结合粉料的DRIFT光谱、离子电导率和可溶性离子浓度、以及表面氧含量的分析，总结了氮化硅粉料分散性能较差的限制性因素，提出1种普适性的制备氮化硅水基浓悬浮体的新方法。
选用了分散性能较差的4种商业氮化硅粉料，系统研究了表面水解及热氧化处理对氮化硅粉料表面特性及分散性能的影响，并结合粉料的DRIFT光谱、离子电导率和可溶性离子浓度、以及表面氧含量的分析，总结了氮化硅粉料分散性能较差的限制性因素，提出1种普适性的制备氮化硅水基浓悬浮体的新方法。
2005, 34(1):91-94.
Abstract:
The high-temperature oxidation-resistant MoSi2 coating on the Nb substrate was prepared by slurry firing. The structure, composition and phase distribution of the coating and the relationship between these features and the oxidation resistance of the coating were investigated by SEM, EDS, and XRD. The results indicate that the interface between the coating and the substrate is metallurgical bond, and a transitional layer was formed by diffusion. The composite multi-layer structures improve the oxidation resistance properties of the coating. The method of slurry firing to prepare the high temperature MoSi2 coating on Nb was feasible. The SiO2 glass layer, which was formed on the surface of the coating by the self-oxidation of MoSi2, prevents oxygen from further diffusion. After a long time exposure in high temperature oxidizing environment, the porous microstructure was formed as a result of the diffusion of silicon in the coating. Due to further interdiffusion of the element, which takes place between the coating and the substrate, a large number of cavities which run through transversely are formed. The coating was broken through the interface between the body of the coating and the transitional layer.
The high-temperature oxidation-resistant MoSi2 coating on the Nb substrate was prepared by slurry firing. The structure, composition and phase distribution of the coating and the relationship between these features and the oxidation resistance of the coating were investigated by SEM, EDS, and XRD. The results indicate that the interface between the coating and the substrate is metallurgical bond, and a transitional layer was formed by diffusion. The composite multi-layer structures improve the oxidation resistance properties of the coating. The method of slurry firing to prepare the high temperature MoSi2 coating on Nb was feasible. The SiO2 glass layer, which was formed on the surface of the coating by the self-oxidation of MoSi2, prevents oxygen from further diffusion. After a long time exposure in high temperature oxidizing environment, the porous microstructure was formed as a result of the diffusion of silicon in the coating. Due to further interdiffusion of the element, which takes place between the coating and the substrate, a large number of cavities which run through transversely are formed. The coating was broken through the interface between the body of the coating and the transitional layer.
2005, 34(1):95-97.
Abstract:
研究了添加0．5at％和1．0at％Zr对钐铁合金微结构和相组成的影响。添加和不添加Zr的Sm-Fe合金相比，发现添加1．0at％Zr可以基本消除铸态组织中的α-Fe，并且能同时减少富钐相。多添加18at％Sm的Sm-Fe合金退火后，仍残留少量的α-Fe，而添加1．0at％Zr的Sm-Fe-Zr合金退火后主相Sm2Fe17以及α-Fe的量没有明显的变化，因此有可能避免过长的均匀化退火过程。
研究了添加0．5at％和1．0at％Zr对钐铁合金微结构和相组成的影响。添加和不添加Zr的Sm-Fe合金相比，发现添加1．0at％Zr可以基本消除铸态组织中的α-Fe，并且能同时减少富钐相。多添加18at％Sm的Sm-Fe合金退火后，仍残留少量的α-Fe，而添加1．0at％Zr的Sm-Fe-Zr合金退火后主相Sm2Fe17以及α-Fe的量没有明显的变化，因此有可能避免过长的均匀化退火过程。
2005, 34(1):98-101.
Abstract:
采用差示扫描量热仪(DSC)研究了大块金属玻璃Pd40Ni10Cu30P20的结构弛豫。结果表明金属玻璃Pd40Ni10Cu30P20的结构驰豫可分为2个阶段：在400K～520K的温度范围，样品发生的是低温结构弛豫，所伴随的结构变化是局域的和短程的，自由体积没有发生明显湮灭，所以样品的密度变化不大。而在520K～玻璃转变温度Tg的温度范围，样品发生的是高温结构弛豫，在这一过程中发生原子的中长程扩散，部分自由体积通过样品表面发生湮灭，因而导致样品的密度显著增加。实验还表明，在Tg以下进行预退火处理使得大块金属玻璃Pd40Ni10Cu30P20的玻璃转变激活能明显降低，但对后续的晶化过程的影响不大。
采用差示扫描量热仪(DSC)研究了大块金属玻璃Pd40Ni10Cu30P20的结构弛豫。结果表明金属玻璃Pd40Ni10Cu30P20的结构驰豫可分为2个阶段：在400K～520K的温度范围，样品发生的是低温结构弛豫，所伴随的结构变化是局域的和短程的，自由体积没有发生明显湮灭，所以样品的密度变化不大。而在520K～玻璃转变温度Tg的温度范围，样品发生的是高温结构弛豫，在这一过程中发生原子的中长程扩散，部分自由体积通过样品表面发生湮灭，因而导致样品的密度显著增加。实验还表明，在Tg以下进行预退火处理使得大块金属玻璃Pd40Ni10Cu30P20的玻璃转变激活能明显降低，但对后续的晶化过程的影响不大。
2005, 34(1):102-106.
Abstract:
Joining of Si3N4 / Si3N4 was carried out by using Cu68Ti20Ni12 fill metal. The results show that brazing temperature and holding time have an important influence on joining strength, and the highest strength value (289 MPa) was achieved at the brazing temperature of 1 373 K for 10 minutes. Microanalysis of the Si3N4/ Cu68Ti20Ni12 interfacial region showthat Ti and Ni concentrate towards Si3N4 and the enriched area of Ti is closer to Si3N4 ceramics, while Si diffuses towards braze layer and Cu element is concentrated in the center part of the joint; Interfacial region has two reaction layer. Reaction layer I is TiN while reaction layer II consists of TiN, Ti5Si4, Ti5Si3, Ni3Si and NiTi compounds .
Joining of Si3N4 / Si3N4 was carried out by using Cu68Ti20Ni12 fill metal. The results show that brazing temperature and holding time have an important influence on joining strength, and the highest strength value (289 MPa) was achieved at the brazing temperature of 1 373 K for 10 minutes. Microanalysis of the Si3N4/ Cu68Ti20Ni12 interfacial region showthat Ti and Ni concentrate towards Si3N4 and the enriched area of Ti is closer to Si3N4 ceramics, while Si diffuses towards braze layer and Cu element is concentrated in the center part of the joint; Interfacial region has two reaction layer. Reaction layer I is TiN while reaction layer II consists of TiN, Ti5Si4, Ti5Si3, Ni3Si and NiTi compounds .
2005, 34(1):107-111.
Abstract:
为了研究高能氪离子轰击对纯锆水溶液中耐蚀性能的影响,纯锆样品用LC-4型离子注入机在40℃温度下进行高能氪离子轰击,注入剂量从1×1015ions/cm2到3×1016ions/cm2,注入能量为300keV。用X-射线光电子谱(XPS)分析注入表层元素价态,俄歇电子谱(AES)测试氧化膜的深度分布,用透射电镜(TEM)观察轰击样品的形貌和结构转变,轰击样品在1N硫酸溶液中的耐蚀性能用动电位极化测量曲线表征。结果表明:高能氪离子轰击样品后其耐蚀性能大大降低,轰击剂量越大,耐蚀性越差。最后讨论了辐照腐蚀的机理。
为了研究高能氪离子轰击对纯锆水溶液中耐蚀性能的影响,纯锆样品用LC-4型离子注入机在40℃温度下进行高能氪离子轰击,注入剂量从1×1015ions/cm2到3×1016ions/cm2,注入能量为300keV。用X-射线光电子谱(XPS)分析注入表层元素价态,俄歇电子谱(AES)测试氧化膜的深度分布,用透射电镜(TEM)观察轰击样品的形貌和结构转变,轰击样品在1N硫酸溶液中的耐蚀性能用动电位极化测量曲线表征。结果表明:高能氪离子轰击样品后其耐蚀性能大大降低,轰击剂量越大,耐蚀性越差。最后讨论了辐照腐蚀的机理。
2005, 34(1):112-115.
Abstract:
Amorphous MgNi hydrogen storage alloy was synthesized by mechanically alloying (MA). The electrochemistry property of the alloy prepared in different parameters was tested. The relationship between the mechanically alloying parameters, the microstructure of the alloy and the electrochemistry property was analyzed. The results show that the eclectrochemistry property of the alloy has a strong relationship with milling speed, ball/powder weight ration(R) and milling time.
Amorphous MgNi hydrogen storage alloy was synthesized by mechanically alloying (MA). The electrochemistry property of the alloy prepared in different parameters was tested. The relationship between the mechanically alloying parameters, the microstructure of the alloy and the electrochemistry property was analyzed. The results show that the eclectrochemistry property of the alloy has a strong relationship with milling speed, ball/powder weight ration(R) and milling time.
2005, 34(1):116-119.
Abstract:
Carbonized La-Mo cathode applied in FU105 large powerful broadcast emission tube has been studied. Referred to carbonized Th-W cathode , the carbonizing techniques of La-Mo cathode was worked out. Exhausting and seasoning of carbonized La-Mo cathode for FU105 tube were carried out. Through the performance test of FU105 tube equipped with La-Mo cathode, the emission capacity and stabilization of carbonized La-Mo cathode were analyzed. The results show that the emission capacity of carbonized La-Mo cathode for FU105 tube has reached that of Th-W cathode, but its emission stabilization is not very good.
Carbonized La-Mo cathode applied in FU105 large powerful broadcast emission tube has been studied. Referred to carbonized Th-W cathode , the carbonizing techniques of La-Mo cathode was worked out. Exhausting and seasoning of carbonized La-Mo cathode for FU105 tube were carried out. Through the performance test of FU105 tube equipped with La-Mo cathode, the emission capacity and stabilization of carbonized La-Mo cathode were analyzed. The results show that the emission capacity of carbonized La-Mo cathode for FU105 tube has reached that of Th-W cathode, but its emission stabilization is not very good.
2005, 34(1):120-123.
Abstract:
摘要：利用真空甩带机制备了Fe84Zr2．08Nb1．92Cu1B11金属快淬薄带。X射线衍射结果表明：薄带经570℃退火后析出纳米化结构bccα-Fe相，晶粒大小约为20nm～40nm，利用HP4294A阻抗分析仪测量了此纳米晶薄带中的巨磁阻抗效应。结果显示在低频下阻抗随外磁场单调减小，这主要是由于磁导率随外磁场的变化导致的，高频下阻抗随外磁场变化出现1个峰值，这主要是由于横向各向异性的原因。运用计算机模拟了这一结果，发现磁导率随外磁场的变化在外场与各向异性场的比值约为0．9处出现了峰值，巨磁阻抗效应也在此位置出现峰值。并且随着驱动电流频率的增大峰值变大。
摘要：利用真空甩带机制备了Fe84Zr2．08Nb1．92Cu1B11金属快淬薄带。X射线衍射结果表明：薄带经570℃退火后析出纳米化结构bccα-Fe相，晶粒大小约为20nm～40nm，利用HP4294A阻抗分析仪测量了此纳米晶薄带中的巨磁阻抗效应。结果显示在低频下阻抗随外磁场单调减小，这主要是由于磁导率随外磁场的变化导致的，高频下阻抗随外磁场变化出现1个峰值，这主要是由于横向各向异性的原因。运用计算机模拟了这一结果，发现磁导率随外磁场的变化在外场与各向异性场的比值约为0．9处出现了峰值，巨磁阻抗效应也在此位置出现峰值。并且随着驱动电流频率的增大峰值变大。
2005, 34(1):124-127.
Abstract:
Rare-earth composite oxide DyFeO3 was synthesized by adopting sol-gel method in citrate which belongs to the structure of peroviskite. Structural characteristics characterized by XRD and TEM indicate that this material is nanosized. The crystal structure shows a certain amount of lattice distortion due to the decrease of the grain size and the increase of the surface area. This material was made into gas sensors and measured its gas-sensing properties to ethanol, CO, H2, H2S etc. The results show that the sensors based on DyFeO3 have high sensitivity ,excellent selectivity and quick response&recovery behavior to H2S.
Rare-earth composite oxide DyFeO3 was synthesized by adopting sol-gel method in citrate which belongs to the structure of peroviskite. Structural characteristics characterized by XRD and TEM indicate that this material is nanosized. The crystal structure shows a certain amount of lattice distortion due to the decrease of the grain size and the increase of the surface area. This material was made into gas sensors and measured its gas-sensing properties to ethanol, CO, H2, H2S etc. The results show that the sensors based on DyFeO3 have high sensitivity ,excellent selectivity and quick response&recovery behavior to H2S.
2005, 34(1):128-131.
Abstract:
Wear properties of TC4 alloy were systematically tested in air and vacuum (10-5Pa). The effects of load and sliding velocity on the wear rate of TC4 alloy were studied, and the microstructural analysis of the worn surface layer of TC4 alloy were carried out. In air, the microstructure of the surface layer presented slid band of dislocation at the lower sliding velocity, and micro-crack at the higher sliding velocity. In vacuum, the microstructure of the surface layer was refined to a gain size range of 50 nm~100 nm and comprised of high density of dislocations. Twins existed in the substructure of the surface layer at higher sliding velocities.
Wear properties of TC4 alloy were systematically tested in air and vacuum (10-5Pa). The effects of load and sliding velocity on the wear rate of TC4 alloy were studied, and the microstructural analysis of the worn surface layer of TC4 alloy were carried out. In air, the microstructure of the surface layer presented slid band of dislocation at the lower sliding velocity, and micro-crack at the higher sliding velocity. In vacuum, the microstructure of the surface layer was refined to a gain size range of 50 nm~100 nm and comprised of high density of dislocations. Twins existed in the substructure of the surface layer at higher sliding velocities.
2005, 34(1):132-134.
Abstract:
利用放电等离子烧结技术研究了SHS的Ti3AlC2粉体的烧结过程。烧结温度1450℃，压力20MPa，真空烧结，保温5min，可获得相对密度达98．4％的致密烧结体，HV可达3．8GPa；烧结温度为l500℃，则可获得完全致密的烧结体，HV可达4．2GPa；烧结体的维氏硬度随烧结温度(1300℃～1500℃)的升高而增大；SEM分析表明，SPS技术烧结制备的Ti3AlC2陶瓷，片层大小随烧结温度的升高而增大。
利用放电等离子烧结技术研究了SHS的Ti3AlC2粉体的烧结过程。烧结温度1450℃，压力20MPa，真空烧结，保温5min，可获得相对密度达98．4％的致密烧结体，HV可达3．8GPa；烧结温度为l500℃，则可获得完全致密的烧结体，HV可达4．2GPa；烧结体的维氏硬度随烧结温度(1300℃～1500℃)的升高而增大；SEM分析表明，SPS技术烧结制备的Ti3AlC2陶瓷，片层大小随烧结温度的升高而增大。
2005, 34(1):135-138.
Abstract:
采用电化学测试技术和化学浸泡试验对生物医用TiNi基形状记忆合金在生理盐水中的腐蚀行为进行了研究。结果表明，TiNi合金比TiNiCu合金阳极钝化区拓宽，孔蚀电位正移，腐蚀率减小。通过EDX分析和SEM观察发现，TiNi合金蚀孔内存在富Ti贫Ni的Ti2Ni析出相，而TiNiCu合金存在Cu原子富集的CuNi相，从而验证了这些析出相是萌生孔蚀的敏感位置。在生理盐水中TiNiCu合金的耐蚀性比TiNi合金劣，其原因是TiNiCu合金有较多的残余奥氏体及单斜和斜方的马氏体结构，存在不同晶体结构区域，造成电化学性质不均匀性，从而形成了腐蚀微电池，加速了活性溶解。
采用电化学测试技术和化学浸泡试验对生物医用TiNi基形状记忆合金在生理盐水中的腐蚀行为进行了研究。结果表明，TiNi合金比TiNiCu合金阳极钝化区拓宽，孔蚀电位正移，腐蚀率减小。通过EDX分析和SEM观察发现，TiNi合金蚀孔内存在富Ti贫Ni的Ti2Ni析出相，而TiNiCu合金存在Cu原子富集的CuNi相，从而验证了这些析出相是萌生孔蚀的敏感位置。在生理盐水中TiNiCu合金的耐蚀性比TiNi合金劣，其原因是TiNiCu合金有较多的残余奥氏体及单斜和斜方的马氏体结构，存在不同晶体结构区域，造成电化学性质不均匀性，从而形成了腐蚀微电池，加速了活性溶解。
2005, 34(1):139-142.
Abstract:
在不通入活性气体的条件下，采用三乙酰丙酮铱金属有机物化学气相沉积方法制备铱薄膜。结果表明：低于190℃长时间加热使先驱体分子结构改变，其C-H和C-O键断裂活性升高，导致沉积薄膜中含有显著数量的碳杂质；高于220℃加热先驱体和550℃沉积，可获得致密连续、无杂质碳并且呈亮银白色的铱薄膜。
在不通入活性气体的条件下，采用三乙酰丙酮铱金属有机物化学气相沉积方法制备铱薄膜。结果表明：低于190℃长时间加热使先驱体分子结构改变，其C-H和C-O键断裂活性升高，导致沉积薄膜中含有显著数量的碳杂质；高于220℃加热先驱体和550℃沉积，可获得致密连续、无杂质碳并且呈亮银白色的铱薄膜。
2005, 34(1):143-145.
Abstract:
During semiconductor manufacturing, the gold wire bonding is influenced by the native Al oxide film, and Au wire could not bond to Al bondpad.In this paper, SEM, EDS and AES are used to investigate the bondpads. It's found that the elements on the surface of Al bondpads after sawing are consistent with those of before sawing. So swilling techniques does not affect the wire bonding. The AES results show that there is 40% O element in Al bondpads even though at the depth of half of the Al bondpad height. Consequently, Al has already been oxidized by O. The Al oxide film which can prevent the bonding and the diffusion of O to Al causes the failure of wire bonding.
During semiconductor manufacturing, the gold wire bonding is influenced by the native Al oxide film, and Au wire could not bond to Al bondpad.In this paper, SEM, EDS and AES are used to investigate the bondpads. It's found that the elements on the surface of Al bondpads after sawing are consistent with those of before sawing. So swilling techniques does not affect the wire bonding. The AES results show that there is 40% O element in Al bondpads even though at the depth of half of the Al bondpad height. Consequently, Al has already been oxidized by O. The Al oxide film which can prevent the bonding and the diffusion of O to Al causes the failure of wire bonding.
2005, 34(1):146-149.
Abstract:
Using two kinds of liquid medium and two dispersants, we investigated the dispersed characteristic of Ti(C,N)-based cermet hard phase powders TiC, TiN and WC. It is concluded that: for TiC, TiN, WC powder, aqua is more suitable than ethanol as a kind of liquid medium. For TiC and TiN, aether is an appropriate dispersant but for WC, polyglycolis considered.
Using two kinds of liquid medium and two dispersants, we investigated the dispersed characteristic of Ti(C,N)-based cermet hard phase powders TiC, TiN and WC. It is concluded that: for TiC, TiN, WC powder, aqua is more suitable than ethanol as a kind of liquid medium. For TiC and TiN, aether is an appropriate dispersant but for WC, polyglycolis considered.
2005, 34(1):150-153.
Abstract:
研究了真空荧光显示屏阵列材料FeNi42Cr6合金在高温湿氢气氛中的氧化行为。其氧化过程为：首先形成Cr2O3，然后(Fe,Mn)Cr2O4氧化物形核、生长，形成完整氧化膜，成熟氧化膜由颗粒状刚玉型氧化物Cr2O3和块状尖晶石型(Fe,Mn)Cr2O4氧化物组成。实验同时表明，阵列板电阻率随氧化膜厚度增加而增大，电阻率过高会导致与之焊接的Ni丝熔断，氧化膜厚度应控制在1μm～2μm。借助扫描电镜、X射线衍射研究了氧化时间、氢气流量、氢气露点等工艺参数对阵列板氧化增重、氧化膜相结构及、氧化膜表面形貌的影响。得出氧化温度为950℃，时间40min～60min，氢气露点(dp)35℃，流量8L／mm为最佳阵列材料氧化工艺。
研究了真空荧光显示屏阵列材料FeNi42Cr6合金在高温湿氢气氛中的氧化行为。其氧化过程为：首先形成Cr2O3，然后(Fe,Mn)Cr2O4氧化物形核、生长，形成完整氧化膜，成熟氧化膜由颗粒状刚玉型氧化物Cr2O3和块状尖晶石型(Fe,Mn)Cr2O4氧化物组成。实验同时表明，阵列板电阻率随氧化膜厚度增加而增大，电阻率过高会导致与之焊接的Ni丝熔断，氧化膜厚度应控制在1μm～2μm。借助扫描电镜、X射线衍射研究了氧化时间、氢气流量、氢气露点等工艺参数对阵列板氧化增重、氧化膜相结构及、氧化膜表面形貌的影响。得出氧化温度为950℃，时间40min～60min，氢气露点(dp)35℃，流量8L／mm为最佳阵列材料氧化工艺。
2005, 34(1):154-157.
Abstract:
The effect of Nd2O3 on voltage and microstructure of ZnO varistor was studied, and a theoretical analysis of the mechanism of the effect was conducted. The results show that the voltage of ZnO varistor increases with the increase of Nd2O3 content in the range of 0 mol%~0.04 mol%. But when the content of Nd2O3 is more than 0.04 mol%, the voltage of ZnO varistor decreases with the increase of the content. The microstructure analysis indicates that the minimal additive exists in ZnO grain boundary in the form of a new compound and hinders the movement of grain boundary, which reduces the size of ZnO grain size and makes the grain more uniform, and as a result, Nd2O3 improve the voltage of the varistor greatly.
The effect of Nd2O3 on voltage and microstructure of ZnO varistor was studied, and a theoretical analysis of the mechanism of the effect was conducted. The results show that the voltage of ZnO varistor increases with the increase of Nd2O3 content in the range of 0 mol%~0.04 mol%. But when the content of Nd2O3 is more than 0.04 mol%, the voltage of ZnO varistor decreases with the increase of the content. The microstructure analysis indicates that the minimal additive exists in ZnO grain boundary in the form of a new compound and hinders the movement of grain boundary, which reduces the size of ZnO grain size and makes the grain more uniform, and as a result, Nd2O3 improve the voltage of the varistor greatly.
2005, 34(1):158-161.
Abstract:
采用热压烧结的方法制备了镍铁尖晶石基金属陶瓷试样,用于铝电解的惰性阳极。实验制得了相对密度大于98%的阳极试样,并研究了试样的导电性能和抗电解质腐蚀性能。结果表明,所得的阳极试样的电导率随温度的升高而增大,在900℃时电导率在40Ω-1·cm-1~60Ω-1·cm-1之间。在电解过程中,阳极电压降平稳(2.8V~3.2V),表明阳极的电阻在电解过程中没有明显变化,导电性能稳定。用反电动势法测量电解反应的分解电压为2.2V~2.5V,表明电解反应为2Al2O3=4Al+3O2,电极呈现良好的惰性。电子显微分析表明,试样抗冰晶石-氧化铝熔盐腐蚀的性能良好,电解质通过对Fe2O3的溶解来腐蚀阳极。
采用热压烧结的方法制备了镍铁尖晶石基金属陶瓷试样,用于铝电解的惰性阳极。实验制得了相对密度大于98%的阳极试样,并研究了试样的导电性能和抗电解质腐蚀性能。结果表明,所得的阳极试样的电导率随温度的升高而增大,在900℃时电导率在40Ω-1·cm-1~60Ω-1·cm-1之间。在电解过程中,阳极电压降平稳(2.8V~3.2V),表明阳极的电阻在电解过程中没有明显变化,导电性能稳定。用反电动势法测量电解反应的分解电压为2.2V~2.5V,表明电解反应为2Al2O3=4Al+3O2,电极呈现良好的惰性。电子显微分析表明,试样抗冰晶石-氧化铝熔盐腐蚀的性能良好,电解质通过对Fe2O3的溶解来腐蚀阳极。
2005, 34(1):162-165.
Abstract:
Cu elements have been introduced into the Ti-6Al-4V substrate by using double glow plasma surface alloying technology to form burn-resistant alloyed layer on the surface. Composition and hardness in the alloyed surface layer gradually change in the depth direction of the substrate and its microstructure is substrate microstructure plus diffused Ti2Cu intermetallics. Abecedarian tests reveal that the copperized alloying layer has the function of burn-resistance.
Cu elements have been introduced into the Ti-6Al-4V substrate by using double glow plasma surface alloying technology to form burn-resistant alloyed layer on the surface. Composition and hardness in the alloyed surface layer gradually change in the depth direction of the substrate and its microstructure is substrate microstructure plus diffused Ti2Cu intermetallics. Abecedarian tests reveal that the copperized alloying layer has the function of burn-resistance.
39 Photoluminescence Study of GaN Film Grown by Ammoniating Ga2O3/Al2O3 Deposited on Si(111) Substrate
2005, 34(1):166-168.
Abstract:
Photoluminescence(PL) of Gallium nitride (GaN) films grown by ammoniating Ga2O3/Al2O3 films deposited on silicon (111) by rf magnetron sputtering has been studied. The mechanism and the influence of growth condition on the photoluminescence is also studied. There are two emission peaks: a strong one at 347 nm, and a weak one at 412 nm. Increasing the ammoniating temperature and lengthening the ammoniating time, the intensities of both two peaks increase, but the in locations do not move. The peak at 347 nm is considered to be the blue-shift, which was caused by micro- size of GaN grains, of the band-edge emission peak of GaN. The emission peak at 412 nm is attributed to radiant combination from conduct band to the energy level of acceptor impurity.
Photoluminescence(PL) of Gallium nitride (GaN) films grown by ammoniating Ga2O3/Al2O3 films deposited on silicon (111) by rf magnetron sputtering has been studied. The mechanism and the influence of growth condition on the photoluminescence is also studied. There are two emission peaks: a strong one at 347 nm, and a weak one at 412 nm. Increasing the ammoniating temperature and lengthening the ammoniating time, the intensities of both two peaks increase, but the in locations do not move. The peak at 347 nm is considered to be the blue-shift, which was caused by micro- size of GaN grains, of the band-edge emission peak of GaN. The emission peak at 412 nm is attributed to radiant combination from conduct band to the energy level of acceptor impurity.
