Volume 33,Issue 8,2004 Table of Contents
2004, 33(8):785-788.
Abstract:
The Al2O3/Ni composite brush plating coating with homogeneous distribution and good bonding with matrix metal Ni was prepared through adding nano-Al2O3 grains into the Ni-base electro-brush plating bath. The microstructures of the composite brush plating coating are superior to the common rapid Ni-base brush plating coating. The tribological results show that the abrasion-proof of the composite plating coating is better than that of the common plating coating not only at room temperature but also at high temperature. It is found that the plastic deformation-resistance and adhesion reduction performances of the composite plating coating were improved under strengthening effect of nano-Al2O3 grains.
The Al2O3/Ni composite brush plating coating with homogeneous distribution and good bonding with matrix metal Ni was prepared through adding nano-Al2O3 grains into the Ni-base electro-brush plating bath. The microstructures of the composite brush plating coating are superior to the common rapid Ni-base brush plating coating. The tribological results show that the abrasion-proof of the composite plating coating is better than that of the common plating coating not only at room temperature but also at high temperature. It is found that the plastic deformation-resistance and adhesion reduction performances of the composite plating coating were improved under strengthening effect of nano-Al2O3 grains.
2004, 33(8):789-792.
Abstract:
LiMnO2 and LiMn0.9Cr0.1O2 were prepared by a high temperature solid-state route. In comparison with orthorhombic LiMnO2, monoclinic LiMnO2 was formed with Cr substitution. The research shows that the irreversible transformation to spinel-like structure during LiMnO2 cycling is a gradual phase transformation process. In comparison with the 2.9 V and 4 V plateaus of LiMnO2, LiMn0.9Cr0.1O2 shows only 2.9 V plateau for further cycling. So it is clear that the electrochemistry behavior change from LiMnO2 to LiMn0.9Cr0.1O2 phase is due to doping of Cr.
LiMnO2 and LiMn0.9Cr0.1O2 were prepared by a high temperature solid-state route. In comparison with orthorhombic LiMnO2, monoclinic LiMnO2 was formed with Cr substitution. The research shows that the irreversible transformation to spinel-like structure during LiMnO2 cycling is a gradual phase transformation process. In comparison with the 2.9 V and 4 V plateaus of LiMnO2, LiMn0.9Cr0.1O2 shows only 2.9 V plateau for further cycling. So it is clear that the electrochemistry behavior change from LiMnO2 to LiMn0.9Cr0.1O2 phase is due to doping of Cr.
2004, 33(8):793-796.
Abstract:
为了提高Bi-2212/Ag带的性能（主要指临界电流密度Jc)，进行了部分熔化热处理工艺对带材Jc的实验。采用标准的4点法测量Jc,使用PW1700XRD,SL20 SEM 和EDX检验和研究带材的相组成和微观组织。实验表明，在流氧气氛下，烧结温度为860℃～880℃时，前驱粉末以Bi-2212为主相，同时含有少量的Bi-2201相，（Sr2Ca)Cu2O3相和富（Bi2Sr)相。在流氧气氛下，带材Jc性能对热处理工艺参数非常敏感，在实验条件范围内，优化后的热处理工艺参数为：熔化温度Tmax=890℃，熔化时间tmax=10min,冷却速率Rc=2℃h^-1，在保温温度为835℃时，保温时间ta=20h,通过优化的部分熔化热处理工艺，在77K，0T下最后所制得带材的最大Jc=6A,Jc=890Acm^-2.
为了提高Bi-2212/Ag带的性能（主要指临界电流密度Jc)，进行了部分熔化热处理工艺对带材Jc的实验。采用标准的4点法测量Jc,使用PW1700XRD,SL20 SEM 和EDX检验和研究带材的相组成和微观组织。实验表明，在流氧气氛下，烧结温度为860℃～880℃时，前驱粉末以Bi-2212为主相，同时含有少量的Bi-2201相，（Sr2Ca)Cu2O3相和富（Bi2Sr)相。在流氧气氛下，带材Jc性能对热处理工艺参数非常敏感，在实验条件范围内，优化后的热处理工艺参数为：熔化温度Tmax=890℃，熔化时间tmax=10min,冷却速率Rc=2℃h^-1，在保温温度为835℃时，保温时间ta=20h,通过优化的部分熔化热处理工艺，在77K，0T下最后所制得带材的最大Jc=6A,Jc=890Acm^-2.
2004, 33(8):797-803.
Abstract:
By analyzing the kinetics of thermal debinding, shifting of different controlling mechanism was found in the debinding process. The definition of critical thickness was specifically put forward for the first in this article. Big critical thickness means fast initial heating can be performed, which means the time for debinding can be comparatively shorter. To avoid defects such as blisters, cracks and distortion, heating of compacts with small critical thickness should be very slow. In debinding practice big critical thickness is more favorable. Theoretical calculation of controlling steps show that critical thickness depends on the flowing factor: powder size, debinding temperature and solid loading; its directly proportional to powder sizes, its inversely proportional to temperature and solid loading rate.
By analyzing the kinetics of thermal debinding, shifting of different controlling mechanism was found in the debinding process. The definition of critical thickness was specifically put forward for the first in this article. Big critical thickness means fast initial heating can be performed, which means the time for debinding can be comparatively shorter. To avoid defects such as blisters, cracks and distortion, heating of compacts with small critical thickness should be very slow. In debinding practice big critical thickness is more favorable. Theoretical calculation of controlling steps show that critical thickness depends on the flowing factor: powder size, debinding temperature and solid loading; its directly proportional to powder sizes, its inversely proportional to temperature and solid loading rate.
2004, 33(8):804-807.
Abstract:
Abnormal morphology appears easily in the cross section of cold-pilgered zirconium alloy bar due to improper die design or/and improper deformation ratio distribution. Causes and its effects on usability were investigated in this paper by optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffraction(XRD), hardness and density, etc. Studying results prove that such abnormal phenomena are not exhibition of defects; however result from preferred orientation with low acid corrosion resistance brought by cold pilgering; such abnormal phenomena have no effects on usability of cold-pilgered bars, cold-pilgered zirconium alloy bar with abnormal phenomena can still serve reactors safely.
Abnormal morphology appears easily in the cross section of cold-pilgered zirconium alloy bar due to improper die design or/and improper deformation ratio distribution. Causes and its effects on usability were investigated in this paper by optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffraction(XRD), hardness and density, etc. Studying results prove that such abnormal phenomena are not exhibition of defects; however result from preferred orientation with low acid corrosion resistance brought by cold pilgering; such abnormal phenomena have no effects on usability of cold-pilgered bars, cold-pilgered zirconium alloy bar with abnormal phenomena can still serve reactors safely.
2004, 33(8):811-814.
Abstract:
The effects of small addition of scandium on the microstructure and ageing characteristics in Al-2.5Cu-1.5Mg alloys have been investigated. The results indicate that the age hardening response of the Al-2.5Cu-1.5Mg alloy can be enhanced while the general form of the ageing curve is not altered by small addition of Sc. TEM observations show that GPB can only precipitated during the second age hardening period which will make a great contribution to the age hardening, and the morphology of GPB can be modified by the small addition of Sc, which does result in a refinement of the distribution of GPB in Al-2.5Cu-1.5Mg-0.2Sc.
The effects of small addition of scandium on the microstructure and ageing characteristics in Al-2.5Cu-1.5Mg alloys have been investigated. The results indicate that the age hardening response of the Al-2.5Cu-1.5Mg alloy can be enhanced while the general form of the ageing curve is not altered by small addition of Sc. TEM observations show that GPB can only precipitated during the second age hardening period which will make a great contribution to the age hardening, and the morphology of GPB can be modified by the small addition of Sc, which does result in a refinement of the distribution of GPB in Al-2.5Cu-1.5Mg-0.2Sc.
7 Simulation of Die Filling Process During Injection Molding of Cemented Carbide Feedstock with Ansys
2004, 33(8):815-818.
Abstract:
以流体力学和热力学理论为基础，结合金属注射成形的特点，建立了其充模流动过程中的控制方程、初始条件和边界条件，并以硬质合金材料为例，采用大型有限元软件ANSYS进行了计算数值模拟，求解了流体前沿、温度场、压力场，同时结合实验分析了金属注射成形过程中的几种常见缺陷的产生条件。模拟结果表明：当采用中间浇口、模温60℃、料温160℃、体积流速在40cm^3／s～70cm^3／s的范围内进行注射可以得到良好的硬质合金Ⅰ型拉伸试样预成形坯。该结论与实验结果一致。
以流体力学和热力学理论为基础，结合金属注射成形的特点，建立了其充模流动过程中的控制方程、初始条件和边界条件，并以硬质合金材料为例，采用大型有限元软件ANSYS进行了计算数值模拟，求解了流体前沿、温度场、压力场，同时结合实验分析了金属注射成形过程中的几种常见缺陷的产生条件。模拟结果表明：当采用中间浇口、模温60℃、料温160℃、体积流速在40cm^3／s～70cm^3／s的范围内进行注射可以得到良好的硬质合金Ⅰ型拉伸试样预成形坯。该结论与实验结果一致。
2004, 33(8):819-822.
Abstract:
采用循环水淬和脉冲激光冲击法并结合有限元计算考察和分析了用超高压梯度烧结方法制备的W／Cu FGM的抗热震性能。结果表明，W／Cu FGM经受50次800℃～25℃水淬冲击和100MW／m^2以上的激光循环冲击，没有出现界面破坏现象；但随着热冲击次数及冲击能量密度的增加，金属W表面产生了裂纹、晶间断裂以及出现液相及蒸发现象。与非梯度材料相比，W／Cu FGM有优异的抗热冲击性能，大致可以经受100MW／m^2 350次以上的激光循环冲击。
采用循环水淬和脉冲激光冲击法并结合有限元计算考察和分析了用超高压梯度烧结方法制备的W／Cu FGM的抗热震性能。结果表明，W／Cu FGM经受50次800℃～25℃水淬冲击和100MW／m^2以上的激光循环冲击，没有出现界面破坏现象；但随着热冲击次数及冲击能量密度的增加，金属W表面产生了裂纹、晶间断裂以及出现液相及蒸发现象。与非梯度材料相比，W／Cu FGM有优异的抗热冲击性能，大致可以经受100MW／m^2 350次以上的激光循环冲击。
2004, 33(8):823-826.
Abstract:
The specific heat capacity of ternary liquid Al85Ni10M5 alloys (addition elements M include Si, Mn, Ti and Ce) has been investigated using differential scanning calorimetry (DSC). Experimental results show that a hump occurs on the curve of specific heat capacity of Al85Ni10M5 alloys at elevated temperatures. The position of the hump shifts to a higher temperature with increasing atomic radius and decreasing electronegativity of addition elements. Furthermore, the specific heat capacity of ternary liquid Al85Ni10M5 alloys tends to descend at higher temperatures. The variation of specific heat capacity of liquid alloys with temperature shows that the micro-inhomogeneity exists in the liquid alloys.
The specific heat capacity of ternary liquid Al85Ni10M5 alloys (addition elements M include Si, Mn, Ti and Ce) has been investigated using differential scanning calorimetry (DSC). Experimental results show that a hump occurs on the curve of specific heat capacity of Al85Ni10M5 alloys at elevated temperatures. The position of the hump shifts to a higher temperature with increasing atomic radius and decreasing electronegativity of addition elements. Furthermore, the specific heat capacity of ternary liquid Al85Ni10M5 alloys tends to descend at higher temperatures. The variation of specific heat capacity of liquid alloys with temperature shows that the micro-inhomogeneity exists in the liquid alloys.
2004, 33(8):827-830.
Abstract:
The 7075 aluminum alloy is forged at different strain in different ways. OM(optical microscope) and TEM(transmission electric microscope) were employed to observe the microstructure of 7075 aluminum alloy after hot deformation. Experiment results indicated that 7075 aluminum can occur dynamic recrystallization under hot forging and fine grain can be obtained at the same time, whose recrystallization mechanism and nucleation mechanism are discontinuous dynamic recrystallization and subgrain rotation and polymerization respectively. Its critical strain value is related to deformation pass, the more passes are, the smaller critical strain value will become. Recrystallized grain size decreases with increase of strain, and dispersed second-phase particles play a very important role during dynamic recrystallization.
The 7075 aluminum alloy is forged at different strain in different ways. OM(optical microscope) and TEM(transmission electric microscope) were employed to observe the microstructure of 7075 aluminum alloy after hot deformation. Experiment results indicated that 7075 aluminum can occur dynamic recrystallization under hot forging and fine grain can be obtained at the same time, whose recrystallization mechanism and nucleation mechanism are discontinuous dynamic recrystallization and subgrain rotation and polymerization respectively. Its critical strain value is related to deformation pass, the more passes are, the smaller critical strain value will become. Recrystallized grain size decreases with increase of strain, and dispersed second-phase particles play a very important role during dynamic recrystallization.
2004, 33(8):831-834.
Abstract:
Many H+ response characteristics of Iridium oxide electrode were described in this paper. The linear relationship between open-circuit potential and pH value, decisive factors to response rate were studied in detail. The hysteresis effect were also investigated, furthermore, many determination technologies, such as cyclic voltammetry, SEM, XPS were used to analyze the element valence and composition or to decide the rate of inner and outer surface, as well as to observe the morphology of the oxide film, from which the relationship between hysteresis effect and film thickness as well as morphology was discussed, finally, the response mechanism of the hydrous iridium oxide electrode were suggested.
Many H+ response characteristics of Iridium oxide electrode were described in this paper. The linear relationship between open-circuit potential and pH value, decisive factors to response rate were studied in detail. The hysteresis effect were also investigated, furthermore, many determination technologies, such as cyclic voltammetry, SEM, XPS were used to analyze the element valence and composition or to decide the rate of inner and outer surface, as well as to observe the morphology of the oxide film, from which the relationship between hysteresis effect and film thickness as well as morphology was discussed, finally, the response mechanism of the hydrous iridium oxide electrode were suggested.
2004, 33(8):835-838.
Abstract:
The phase structure and dislocations in rapidly solidified AZ91D magnesium alloy were studied by TEM and XRD techniques. It shows that under rapid solidification conditions, the common eutectic transformation La-Mg+ Mg17Al12 in AZ91D alloys is suppressed to a great extent. As a consequence, the rapid solidification microstructures consist dominantly of supersaturated a-Mg solid solution, whose size is in the range of 0.8~6.0 m. TEM analysis reveals that little amount of oval Mg17Al12 granules, trace polygonal Al8Mn5 particles and very small anomalistic -AlMg phase with the size of 5~70nm precipitate in a-Mg grains or their boundaries. The -AlMg phase is metastable transition configurations which is further transformed into stable Mg17Al12 phase. There are large numbers of dislocation pile-up and cells with the size of 0.2~0.7m in a-Mg grains, and the high dense dislocations mainly concentrate on the (002) close-packed face and exhibit a remarkable orientation.
The phase structure and dislocations in rapidly solidified AZ91D magnesium alloy were studied by TEM and XRD techniques. It shows that under rapid solidification conditions, the common eutectic transformation La-Mg+ Mg17Al12 in AZ91D alloys is suppressed to a great extent. As a consequence, the rapid solidification microstructures consist dominantly of supersaturated a-Mg solid solution, whose size is in the range of 0.8~6.0 m. TEM analysis reveals that little amount of oval Mg17Al12 granules, trace polygonal Al8Mn5 particles and very small anomalistic -AlMg phase with the size of 5~70nm precipitate in a-Mg grains or their boundaries. The -AlMg phase is metastable transition configurations which is further transformed into stable Mg17Al12 phase. There are large numbers of dislocation pile-up and cells with the size of 0.2~0.7m in a-Mg grains, and the high dense dislocations mainly concentrate on the (002) close-packed face and exhibit a remarkable orientation.
2004, 33(8):839-842.
Abstract:
利用电子能量损失谱(EELS)和俄歇电子能谱(AES)研究室温下铌的初始氧化过程，研究表明：清洁表面铌的EELS的实验值与理论值较为符合；随着氧化程度的加剧，其体等离子体(BP)、表面等离子体(SP)以及价带间跃迁所造成的电子能量损失峰发生了明显的偏移和强弱的变化，也解释了Nb→NbO→NbO2的初始氧化过程；另外，铌在潮湿空气里氧化1周，在其表面只生成很薄一层的Nb2O5氧化层。
利用电子能量损失谱(EELS)和俄歇电子能谱(AES)研究室温下铌的初始氧化过程，研究表明：清洁表面铌的EELS的实验值与理论值较为符合；随着氧化程度的加剧，其体等离子体(BP)、表面等离子体(SP)以及价带间跃迁所造成的电子能量损失峰发生了明显的偏移和强弱的变化，也解释了Nb→NbO→NbO2的初始氧化过程；另外，铌在潮湿空气里氧化1周，在其表面只生成很薄一层的Nb2O5氧化层。
2004, 33(8):843-846.
Abstract:
研究了在300℃~350℃下、变形速率为5.610-3 s-1~1.810-2 s-1和挤压比为111条件下的热挤压,以及350℃下多道次的旋锻对ZM2和ZM5铸造合金的组织和室温拉伸性能的影响规律。结果表明:比之铸态组织,ZM2合金挤压态组织细化明显,晶粒为动态再结晶引起的等轴细晶,室温抗拉强度和延性都有显著升高。后续旋锻进一步使组织得到细化,强度升高而延性下降。变形ZM5合金显示出比T4处理态优异的室温拉伸性能。320C下,随着挤压速率的增大,ZM5合金的b和0.2 减小,增大;固定挤压速率为5.610-3 s-1时,升高挤压温度,ZM5合金的b和0.2减小,而增加。
研究了在300℃~350℃下、变形速率为5.610-3 s-1~1.810-2 s-1和挤压比为111条件下的热挤压,以及350℃下多道次的旋锻对ZM2和ZM5铸造合金的组织和室温拉伸性能的影响规律。结果表明:比之铸态组织,ZM2合金挤压态组织细化明显,晶粒为动态再结晶引起的等轴细晶,室温抗拉强度和延性都有显著升高。后续旋锻进一步使组织得到细化,强度升高而延性下降。变形ZM5合金显示出比T4处理态优异的室温拉伸性能。320C下,随着挤压速率的增大,ZM5合金的b和0.2 减小,增大;固定挤压速率为5.610-3 s-1时,升高挤压温度,ZM5合金的b和0.2减小,而增加。
2004, 33(8):847-851.
Abstract:
The effect of temperature on electric fatigue of PLZT ferroelectric ceramics were studied in this paper. The research results show that the effect of temperature on electric fatigue behaviour of PLZT is significant, the higher the temperature is, the slower the fatigue velocity. The results of temperature dependence of the dielectric constant and microstructure observation by SEM shows that fatigue mechanism was mainly domain wall pining and intergranular microcracking initated by the internal stress concentration.
The effect of temperature on electric fatigue of PLZT ferroelectric ceramics were studied in this paper. The research results show that the effect of temperature on electric fatigue behaviour of PLZT is significant, the higher the temperature is, the slower the fatigue velocity. The results of temperature dependence of the dielectric constant and microstructure observation by SEM shows that fatigue mechanism was mainly domain wall pining and intergranular microcracking initated by the internal stress concentration.
2004, 33(8):852-854.
Abstract:
Cavitation erosions of Fe-26Mn-6Si-7Cr-1Cu and Fe-20Mn-6Si-7Cr-1Cu shape memory alloys were investigated by using an ultrasonic vibratory apparatus. It is showed that both alloys have good cavitation erosion resistance. Fe-26Mn-6Si-7Cr-1Cu alloy is more resistant to cavitation erosion than Fe-20Mn-6Si-7Cr-1Cu alloy, which is mainly attributed to the higher strain-induced martensitic transformation energy and elastic deformation energy under a localized load.
Cavitation erosions of Fe-26Mn-6Si-7Cr-1Cu and Fe-20Mn-6Si-7Cr-1Cu shape memory alloys were investigated by using an ultrasonic vibratory apparatus. It is showed that both alloys have good cavitation erosion resistance. Fe-26Mn-6Si-7Cr-1Cu alloy is more resistant to cavitation erosion than Fe-20Mn-6Si-7Cr-1Cu alloy, which is mainly attributed to the higher strain-induced martensitic transformation energy and elastic deformation energy under a localized load.
2004, 33(8):855-857.
Abstract:
the simulation technology of infinite volume method has been introduced, implemented in the commercial computer program MSC.SuperForge, an approach has been developed to simulate the extrusion forming of aluminium profile with its sequence number of FD-JLB8001 produced by an enterprise and it has been showed a good agreement in tendency with the experimental one. As a result of it ,the design method supported by this technology is feasible for the extrusion die used in the real production of the non-hollow profile.
the simulation technology of infinite volume method has been introduced, implemented in the commercial computer program MSC.SuperForge, an approach has been developed to simulate the extrusion forming of aluminium profile with its sequence number of FD-JLB8001 produced by an enterprise and it has been showed a good agreement in tendency with the experimental one. As a result of it ,the design method supported by this technology is feasible for the extrusion die used in the real production of the non-hollow profile.
2004, 33(8):858-860.
Abstract:
The magnetic fluid was investigated in a gas-liquid reactor made by using plasma activation and ionization reactants at atmospheric pressure. The reaction time was shorted to 2 hours by controlling discharge parameter of plasma and optimizing the thermal decomposition temperature of Fe(CO)5. The magnetic fluid has good fluidity with saturated magnetic intensity of 6.510-2T(non- concentrated). The experiments show that plasma can supply needed activation energy for gas-fluid reactants molecules to recombine and to form magnetic fluid, and it is effective method for synthesis of magnetic fluid.
The magnetic fluid was investigated in a gas-liquid reactor made by using plasma activation and ionization reactants at atmospheric pressure. The reaction time was shorted to 2 hours by controlling discharge parameter of plasma and optimizing the thermal decomposition temperature of Fe(CO)5. The magnetic fluid has good fluidity with saturated magnetic intensity of 6.510-2T(non- concentrated). The experiments show that plasma can supply needed activation energy for gas-fluid reactants molecules to recombine and to form magnetic fluid, and it is effective method for synthesis of magnetic fluid.
2004, 33(8):861-863.
Abstract:
采用NH3为N源，以Ga2O3粉末为Ga源高温氨化形成GaN粉末。用X射线衍射(XRD)、扫描电子显微镜(SEM)、选择区电子衍射(SAED)对粉末进行结构、形貌分析。结果表明：当Ga源温度为850℃时得到六方纤锌矿结构的GaN晶体颗粒。
采用NH3为N源，以Ga2O3粉末为Ga源高温氨化形成GaN粉末。用X射线衍射(XRD)、扫描电子显微镜(SEM)、选择区电子衍射(SAED)对粉末进行结构、形貌分析。结果表明：当Ga源温度为850℃时得到六方纤锌矿结构的GaN晶体颗粒。
2004, 33(8):864-868.
Abstract:
米用常温氨水水解TiOSO4过程中加入自制的表面活性剂制备了超细纳米TiO2粉末，用XRD，TEM和比表面仪对不同煅烧温度下的纳米TiO2粉末结构、粒径大小和比表面等进行了表征，研究了纳米TiO2粉末对甲基橙的光催化降解能力。研究表明煅烧温度在400℃～800℃时得到的纳米TiO2粉末呈锐钛矿结构，粒径约为5．5nm～9．6nm，比表面积高达189．45m^2/g；在850℃煅烧后所得的纳米TiO2粉末为锐钛矿与金红石型混晶结构；在l100℃时得到的纳米TiO2粉末为金红石型纳米TiO2粉末，同时微粒出现团聚且粒径变大。光催化实验表明：纳米TiO2粉末的光催化活性与煅烧温度密切相关，850℃煅烧1．5h所制得的混晶结构纳米TiO2粉末表现出较高的光催化活性。与国产商品纳米锐钛矿型TiO2相比，其降解甲基橙的速率约为国产商品纳米TiO2的1倍。
米用常温氨水水解TiOSO4过程中加入自制的表面活性剂制备了超细纳米TiO2粉末，用XRD，TEM和比表面仪对不同煅烧温度下的纳米TiO2粉末结构、粒径大小和比表面等进行了表征，研究了纳米TiO2粉末对甲基橙的光催化降解能力。研究表明煅烧温度在400℃～800℃时得到的纳米TiO2粉末呈锐钛矿结构，粒径约为5．5nm～9．6nm，比表面积高达189．45m^2/g；在850℃煅烧后所得的纳米TiO2粉末为锐钛矿与金红石型混晶结构；在l100℃时得到的纳米TiO2粉末为金红石型纳米TiO2粉末，同时微粒出现团聚且粒径变大。光催化实验表明：纳米TiO2粉末的光催化活性与煅烧温度密切相关，850℃煅烧1．5h所制得的混晶结构纳米TiO2粉末表现出较高的光催化活性。与国产商品纳米锐钛矿型TiO2相比，其降解甲基橙的速率约为国产商品纳米TiO2的1倍。
2004, 33(8):869-872.
Abstract:
Fabrication of semi-solid LY11 alloy by SIMA (strain-induced melt activation) technique was studied, effects of process parameters, height reduction (), isothermal temperature (Ti) and holding time, on grain size, fractal dimension and grain size distribution were investigated quantitatively. The results show that the height reduction has a great effect on microstructure evolution. Grain growth and spheroidization are promoted with increasing the isothermal temperature or elongating the holding time. Grain size has a Gaussian distribution for all samples. In the adjacent domain of peak point, counts of grains reduced and grain size increased with the decreasing of height reduction, the increasing of isothermal temperature and holding time. Pretreatment condition, i.e. cold or hot deformation, has important effects on microstructure evolution, and deformation of samples is a necessary step in SIMA process.
Fabrication of semi-solid LY11 alloy by SIMA (strain-induced melt activation) technique was studied, effects of process parameters, height reduction (), isothermal temperature (Ti) and holding time, on grain size, fractal dimension and grain size distribution were investigated quantitatively. The results show that the height reduction has a great effect on microstructure evolution. Grain growth and spheroidization are promoted with increasing the isothermal temperature or elongating the holding time. Grain size has a Gaussian distribution for all samples. In the adjacent domain of peak point, counts of grains reduced and grain size increased with the decreasing of height reduction, the increasing of isothermal temperature and holding time. Pretreatment condition, i.e. cold or hot deformation, has important effects on microstructure evolution, and deformation of samples is a necessary step in SIMA process.
2004, 33(8):873-876.
Abstract:
采用柠檬酸sol-gel工艺制备了BaFe12O19／SiO2微晶玻璃陶瓷。结果表明，当体系中SiO2的含量为50mol％，67mol％，Fe／Ba处于5：1～7：1，热处理温度在1000℃～1100℃时可以得到单一BaFe12O19晶相或杂质含量很少的BaFe12O19微晶玻璃陶瓷。利用计算机模式识别技术得到了结果可信的材料合成工艺参数目标优化区，采用模式逆映照对BaFe12O19／SiO2微晶玻璃陶瓷的合成工艺参数进行预报和设计，并通过实验予以验证。
采用柠檬酸sol-gel工艺制备了BaFe12O19／SiO2微晶玻璃陶瓷。结果表明，当体系中SiO2的含量为50mol％，67mol％，Fe／Ba处于5：1～7：1，热处理温度在1000℃～1100℃时可以得到单一BaFe12O19晶相或杂质含量很少的BaFe12O19微晶玻璃陶瓷。利用计算机模式识别技术得到了结果可信的材料合成工艺参数目标优化区，采用模式逆映照对BaFe12O19／SiO2微晶玻璃陶瓷的合成工艺参数进行预报和设计，并通过实验予以验证。
2004, 33(8):877-880.
Abstract:
Titanium based Ru-La-Sn coating anodes with various La compositions are prepared by thermal decomposition. The electrocatalytic activity of coating anode is investigated by open-circuit potential test, cyclic voltammetry test, anodic polarization curve test and alternation current impedance test. The morphology of the coating anode is studied by scanning electron microscope (SEM). It is shown that the prepared temperature has a great influence on the morphology of coating anode. The electrocatalytic ability of coating anode can be improved by doping with rare earth La. The highest activity of the coating anode is associated with the composition corresponding to 0.2 (at mole fraction) La. The increase of activity is attributed to the enhancement of active surface area.
Titanium based Ru-La-Sn coating anodes with various La compositions are prepared by thermal decomposition. The electrocatalytic activity of coating anode is investigated by open-circuit potential test, cyclic voltammetry test, anodic polarization curve test and alternation current impedance test. The morphology of the coating anode is studied by scanning electron microscope (SEM). It is shown that the prepared temperature has a great influence on the morphology of coating anode. The electrocatalytic ability of coating anode can be improved by doping with rare earth La. The highest activity of the coating anode is associated with the composition corresponding to 0.2 (at mole fraction) La. The increase of activity is attributed to the enhancement of active surface area.
2004, 33(8):881-884.
Abstract:
La1.5Mg17Ni0.5 hydrogen storage material was prepared by hydriding combustion synthesis (HCS) or mechanical alloying (MA). It was found that the hydrogen absorption properties of La1.5Mg17Ni0.5 prepared by MA are better than ones by HCS. La1.5Mg17Ni0.5 prepared by MA possesses high hydrogen storage capacity of 6.73 mass% at 523 K for less than 1 min and can absorb 4.92 mass% hydrogen at 423 K. The improvement of hydriding properties can be ascribed to the nonacrystalline formation and appearance of defects and strain during the process of mechanical alloying.
La1.5Mg17Ni0.5 hydrogen storage material was prepared by hydriding combustion synthesis (HCS) or mechanical alloying (MA). It was found that the hydrogen absorption properties of La1.5Mg17Ni0.5 prepared by MA are better than ones by HCS. La1.5Mg17Ni0.5 prepared by MA possesses high hydrogen storage capacity of 6.73 mass% at 523 K for less than 1 min and can absorb 4.92 mass% hydrogen at 423 K. The improvement of hydriding properties can be ascribed to the nonacrystalline formation and appearance of defects and strain during the process of mechanical alloying.
2004, 33(8):885-888.
Abstract:
s: ZrO2 nanoparticles supported on CNTs were prepared by adding CNTs in liquid-disposition process. The TEM photo showed that CNTs and ZrO2 nanoparticles would be separated from each other without the surfactant and be connected well when the surfactant was absorbed on the surface of CNTs. The zeta potential of the CNTs in the solution revealed that the surfactant could help them weltering the aquatic phase and enhance the stability of their dispersion. The surfactant had also functioned as bridges, which hydrophilic groups were jointed with the ZrO2 nanoparticles, and which hydrophobic chains were adhered to the surface of the carbon nanotubes, so the ZrO2 nanoparticles were supported on the surface of the carbon nanotubes through the surfactant.
s: ZrO2 nanoparticles supported on CNTs were prepared by adding CNTs in liquid-disposition process. The TEM photo showed that CNTs and ZrO2 nanoparticles would be separated from each other without the surfactant and be connected well when the surfactant was absorbed on the surface of CNTs. The zeta potential of the CNTs in the solution revealed that the surfactant could help them weltering the aquatic phase and enhance the stability of their dispersion. The surfactant had also functioned as bridges, which hydrophilic groups were jointed with the ZrO2 nanoparticles, and which hydrophobic chains were adhered to the surface of the carbon nanotubes, so the ZrO2 nanoparticles were supported on the surface of the carbon nanotubes through the surfactant.
2004, 33(8):889-892.
Abstract:
Optical hydrogen film materials based on palladium are the most important species of optical hydrogen film materials. They include Pd, Pd/Ni alloy, Pd/WO3, Pd/MoO3, Pd/TiOx and Pd/MoS2 films. This paper outlines the progress in research on optical hydrogen materials based on palladium from preparation, performance to application of these film materials. At present, the preparation of optical hydrogen film materials based on palladium is mainly using sputtering method. The performance of Pd film is the best in all optical hydrogen film materials based on palladium. However, there are some disadvantages such as foaming of Pd film surface, lamination fault sheet and decreasing of cohesion between Pd film and carrier in applications. Thereby, Pd/Ni alloy, Pd/WO3, Pd/MoO3, Pd/TiOx and Pd/MoS2 films are exploited one after another. But there are some problems in researches and applications of these film materials above-mentioned. The problems and direction in study on the materials based on palladium are put forward in discussions of the paper.
Optical hydrogen film materials based on palladium are the most important species of optical hydrogen film materials. They include Pd, Pd/Ni alloy, Pd/WO3, Pd/MoO3, Pd/TiOx and Pd/MoS2 films. This paper outlines the progress in research on optical hydrogen materials based on palladium from preparation, performance to application of these film materials. At present, the preparation of optical hydrogen film materials based on palladium is mainly using sputtering method. The performance of Pd film is the best in all optical hydrogen film materials based on palladium. However, there are some disadvantages such as foaming of Pd film surface, lamination fault sheet and decreasing of cohesion between Pd film and carrier in applications. Thereby, Pd/Ni alloy, Pd/WO3, Pd/MoO3, Pd/TiOx and Pd/MoS2 films are exploited one after another. But there are some problems in researches and applications of these film materials above-mentioned. The problems and direction in study on the materials based on palladium are put forward in discussions of the paper.
2004, 33(8):893-896.
Abstract:
As an important engineering alloy, monotectic alloy has attracted a great deal of attention due to its special microstructures and properties. Study progress of monotectic solidification under the conditions of microgravity, directional solidification, high undercooling and melt-spun rapid solidification was summarized and lastly, the future interesting subjects were presented.
As an important engineering alloy, monotectic alloy has attracted a great deal of attention due to its special microstructures and properties. Study progress of monotectic solidification under the conditions of microgravity, directional solidification, high undercooling and melt-spun rapid solidification was summarized and lastly, the future interesting subjects were presented.
