Volume 33,Issue 2,2004 Table of Contents
2004, 33(2):113-119.
Abstract:
利用二维Miedema坐标参数(Δφ~*和Δn_(ws)~((-1)/3))及加入尺寸因素ΔR/R_A构成的三维化学坐标揭示了水溶液法制备多元合金的非晶形成规律。对109个合金分析表明,在二维和三维坐标中,可分别由一直线和一平面较好的将非晶形成和非形成区区分;非晶化条件为:二维坐标系中,二元系,|Δφ~*|>6.4|Δn_(ws)~((-1)/3)|+0.05;多元系,|Δφ~*|>6.6|Δn_(ws)~((-1)/3)|+0.05。判据的准确率在二元、二元和三元以及二元、三元和四元合金系中分别为:81.9％,82.9％及83.5％;三维坐标系中,二元系,|ΔR/R_A|/0.6+|Δφ~*|/0.12-|Δn_(ws)~((-1)/3)|/0.02=1,多元系,|ΔR/R_A|/0.03+|Δφ~*|/0.1-|Δn_(ws)~((-1)/3)|/0.01=1。在二元及二元和三元系统中,区分的准确率高于82％以及86％;该判据扩展至四元合金系后,准确率仍高于86％。
利用二维Miedema坐标参数(Δφ~*和Δn_(ws)~((-1)/3))及加入尺寸因素ΔR/R_A构成的三维化学坐标揭示了水溶液法制备多元合金的非晶形成规律。对109个合金分析表明,在二维和三维坐标中,可分别由一直线和一平面较好的将非晶形成和非形成区区分;非晶化条件为:二维坐标系中,二元系,|Δφ~*|>6.4|Δn_(ws)~((-1)/3)|+0.05;多元系,|Δφ~*|>6.6|Δn_(ws)~((-1)/3)|+0.05。判据的准确率在二元、二元和三元以及二元、三元和四元合金系中分别为:81.9％,82.9％及83.5％;三维坐标系中,二元系,|ΔR/R_A|/0.6+|Δφ~*|/0.12-|Δn_(ws)~((-1)/3)|/0.02=1,多元系,|ΔR/R_A|/0.03+|Δφ~*|/0.1-|Δn_(ws)~((-1)/3)|/0.01=1。在二元及二元和三元系统中,区分的准确率高于82％以及86％;该判据扩展至四元合金系后,准确率仍高于86％。
2004, 33(2):120-124.
Abstract:
研制出1种细晶的8．5Nb-TiAl基合金，化学成分为Ti-45Al-8．5Nb-0.3W-0．3B(TAWBY)，铸态组织的晶粒度约为25μm。合金中含有一定量的B2 ω相，B2相和ω相的位相关系(110)B2/(0001)ω和[111]B2／/[112^-0]ω。同时，对TAWBY合金的变形试样进行了1250℃，1h和1310℃，0．5h真空退火处理，分别获得了DP和FL组织。对2种组织的试样进行了室、高温拉伸和三点弯曲KIC测试，分析了变形TAWBY合金与K5合金等第3代TiAl基合金的力学性能。结果表明，在760℃～870℃下，高温拉伸性能已达到第3代TiAl基合金的性能。
研制出1种细晶的8．5Nb-TiAl基合金，化学成分为Ti-45Al-8．5Nb-0.3W-0．3B(TAWBY)，铸态组织的晶粒度约为25μm。合金中含有一定量的B2 ω相，B2相和ω相的位相关系(110)B2/(0001)ω和[111]B2／/[112^-0]ω。同时，对TAWBY合金的变形试样进行了1250℃，1h和1310℃，0．5h真空退火处理，分别获得了DP和FL组织。对2种组织的试样进行了室、高温拉伸和三点弯曲KIC测试，分析了变形TAWBY合金与K5合金等第3代TiAl基合金的力学性能。结果表明，在760℃～870℃下，高温拉伸性能已达到第3代TiAl基合金的性能。
2004, 33(2):125-127.
Abstract:
Anatase phase TiO2 thin films were prepared on microscope glass slides by r.f. magnetron sputtering using Ar and O2 mixed gases. Then tantalum modified TiO2 thin film was obtained to improve its photocatalytic activity. The films were characterized by X-ray diffraction (XRD), atomic force microscope (AFM) and UV-VIS spectrophotometer. The results indicated that using of proper quantity of Ta to modify the surface of TiO2 thin film can improve its photocatalytic activity.
Anatase phase TiO2 thin films were prepared on microscope glass slides by r.f. magnetron sputtering using Ar and O2 mixed gases. Then tantalum modified TiO2 thin film was obtained to improve its photocatalytic activity. The films were characterized by X-ray diffraction (XRD), atomic force microscope (AFM) and UV-VIS spectrophotometer. The results indicated that using of proper quantity of Ta to modify the surface of TiO2 thin film can improve its photocatalytic activity.
2004, 33(2):128-131.
Abstract:
Potts Monte Carlo simulations were performed to investigate the process of normal grain growth. The results show that the initial grain size distribution and the quasi-stationary distributions could be described well by the Weibull function or the analytical solution with v<4, rather than the classical Hillert distribution (v=4), where vis a parameter of grain size distribution.
Potts Monte Carlo simulations were performed to investigate the process of normal grain growth. The results show that the initial grain size distribution and the quasi-stationary distributions could be described well by the Weibull function or the analytical solution with v<4, rather than the classical Hillert distribution (v=4), where vis a parameter of grain size distribution.
2004, 33(2):132-135.
Abstract:
采用固相反应法合成出La0.6Sr0.4Co1-yFeyO3体系复合氧化物样品，XRD分析结果证实不同Co／Fe比例的样品中均形成菱形六面体钙钛矿结构，采用固相烧结法制备出致密的La0.6Sr0.4Co1-yFeyO3体系陶瓷。研究结果表明，在室温到900℃温度范围内La0.4Sr0.4CoO3(y=0)的电导率随温度的增加而单调降低，其它Co／Fe比例样品的电导率随着温度的增加出现最大值，电导率达到最大值的温度随Co／Fe比例的降低而提高。在低温段，La0.6Sr0.4Co1-yFeyO3体系的导电行为符合小极子导电机制，导电活化能随Co／Fe比例的降低而增加。
采用固相反应法合成出La0.6Sr0.4Co1-yFeyO3体系复合氧化物样品，XRD分析结果证实不同Co／Fe比例的样品中均形成菱形六面体钙钛矿结构，采用固相烧结法制备出致密的La0.6Sr0.4Co1-yFeyO3体系陶瓷。研究结果表明，在室温到900℃温度范围内La0.4Sr0.4CoO3(y=0)的电导率随温度的增加而单调降低，其它Co／Fe比例样品的电导率随着温度的增加出现最大值，电导率达到最大值的温度随Co／Fe比例的降低而提高。在低温段，La0.6Sr0.4Co1-yFeyO3体系的导电行为符合小极子导电机制，导电活化能随Co／Fe比例的降低而增加。
2004, 33(2):136-139.
Abstract:
对纯锆表面注入了1×10~(16)ions/cm~2～1×10~(17)ions/cm~2的镧离子,并在500℃条件下进行了空气氧化增重研究。用XPS分析了注入的镧、锆的价态;用AES分析了镧锆氧三元素的深度分布;用0.3°小角X光掠射(GAXRD)分析了高温氧化时氧化锆的相转变。结果表明,纯锆表面注入La离子后,其抗高温氧化性能显著提高,且注入剂量越大效果越强,注入氧化膜以La_2O_3和ZrO_22种形式存在;由于La离子的注入,促使形成大量四方相氧化锆(t-ZrO_2),而且减少四方相氧化锆(t-ZrO_2)向单斜相氧化锆(m-ZrO_2)的转变,这是纯锆氧化速率降低的根本原因。
对纯锆表面注入了1×10~(16)ions/cm~2～1×10~(17)ions/cm~2的镧离子,并在500℃条件下进行了空气氧化增重研究。用XPS分析了注入的镧、锆的价态;用AES分析了镧锆氧三元素的深度分布;用0.3°小角X光掠射(GAXRD)分析了高温氧化时氧化锆的相转变。结果表明,纯锆表面注入La离子后,其抗高温氧化性能显著提高,且注入剂量越大效果越强,注入氧化膜以La_2O_3和ZrO_22种形式存在;由于La离子的注入,促使形成大量四方相氧化锆(t-ZrO_2),而且减少四方相氧化锆(t-ZrO_2)向单斜相氧化锆(m-ZrO_2)的转变,这是纯锆氧化速率降低的根本原因。
2004, 33(2):140-143.
Abstract:
采用化学液相共沉淀法制备了掺稀土La的BaPbO3导电陶瓷；用XRD及SEM对粉末的结构和组织进行了研究，从而确定了液相共沉淀法制取Ba1-xLaxPbO3的合成温度：同时讨论了稀土La对BaPbO3粉末合成过程及其电性能的影响。结果表明：采用液相共沉淀法能明显降低BamLaxPbO3粉末的合成温度，提高粉体的合成率，其合成温度大约在650℃左右：添加稀土La对BaPbO3的电阻率的影响呈“W”形状变化，当x=10％mol时Ba1-xLaxPbO3的焙烧温度、组织、电阻率均达到最佳。
采用化学液相共沉淀法制备了掺稀土La的BaPbO3导电陶瓷；用XRD及SEM对粉末的结构和组织进行了研究，从而确定了液相共沉淀法制取Ba1-xLaxPbO3的合成温度：同时讨论了稀土La对BaPbO3粉末合成过程及其电性能的影响。结果表明：采用液相共沉淀法能明显降低BamLaxPbO3粉末的合成温度，提高粉体的合成率，其合成温度大约在650℃左右：添加稀土La对BaPbO3的电阻率的影响呈“W”形状变化，当x=10％mol时Ba1-xLaxPbO3的焙烧温度、组织、电阻率均达到最佳。
2004, 33(2):144-148.
Abstract:
The influence of C and B micro-alloying elements on the microstructures and mechanical properties for high Nb containing TiAl alloy was systematically studied. The B micro-addition has a weak effect on the strengthening, but ribbon or dot shaped TiB2 forms at the lamellar colony boundaries and refines the original colony, which is beneficial to improve the room temperature ductility of high Nb containing TiAl alloy. The precipitation of a large amount of Ti3AlC raises the creep resistance during long time creep for high Nb containing TiAl alloy with micro-addition of C.
The influence of C and B micro-alloying elements on the microstructures and mechanical properties for high Nb containing TiAl alloy was systematically studied. The B micro-addition has a weak effect on the strengthening, but ribbon or dot shaped TiB2 forms at the lamellar colony boundaries and refines the original colony, which is beneficial to improve the room temperature ductility of high Nb containing TiAl alloy. The precipitation of a large amount of Ti3AlC raises the creep resistance during long time creep for high Nb containing TiAl alloy with micro-addition of C.
2004, 33(2):153-156.
Abstract:
Because of their excellent properties, zirconium and its alloys are often applied for engineering use in the nuclear industry, working as fuel cladding and core structural material. In the paper, the effect of yttrium implantation on the electrochemical behavior was studied by the measurement of potentiodynamic polarization curves. It was shown that corrosion resistance of zirconium in acid, temperate and alkaline solutions can be improved by yttrium implantation. The composition and the valence of the yttrium ions in the surface layer were analyzed by X-ray photoemission spectroscopy (XPS), and the mechanism of the corrosion resistance improvement of the yttrium-implanted zirconium was discussed.
Because of their excellent properties, zirconium and its alloys are often applied for engineering use in the nuclear industry, working as fuel cladding and core structural material. In the paper, the effect of yttrium implantation on the electrochemical behavior was studied by the measurement of potentiodynamic polarization curves. It was shown that corrosion resistance of zirconium in acid, temperate and alkaline solutions can be improved by yttrium implantation. The composition and the valence of the yttrium ions in the surface layer were analyzed by X-ray photoemission spectroscopy (XPS), and the mechanism of the corrosion resistance improvement of the yttrium-implanted zirconium was discussed.
2004, 33(2):157-160.
Abstract:
通过化学共沉淀法合成PLZST多晶料，采用XRD和SEM对多晶料进行表征，考察了煅烧温度、过量Pb掺量、退火处理等条件对PLZST多晶料的影响。研究结果表明，化学共沉淀法合成PLZST具有一定的适用范围，在低温750℃下保温2h便能得到单一的钙钛矿相，掺入过量的Pb有利于PLZST晶体的生成，适当的退火处理能促进晶体长大。
通过化学共沉淀法合成PLZST多晶料，采用XRD和SEM对多晶料进行表征，考察了煅烧温度、过量Pb掺量、退火处理等条件对PLZST多晶料的影响。研究结果表明，化学共沉淀法合成PLZST具有一定的适用范围，在低温750℃下保温2h便能得到单一的钙钛矿相，掺入过量的Pb有利于PLZST晶体的生成，适当的退火处理能促进晶体长大。
2004, 33(2):161-165.
Abstract:
Using Gleeble-1500D thermal simulation equipment, the effect of Fe content on the low temperature combustion synthesis process of Fe-Ti-C system and microstructure features of the products were studied in this study. The results show that the ignition temperature of Fe-Ti-C system can be decreased greatly under the action of electric field and great thermal density. Moreover, the effect of Fe on the low temperature combustion synthesis process becomes greater with the increasing of Fe content. And the ignition temperature becomes higher, the delay time of ignition becomes shorter and the highest temperature becomes higher with the increasing of Fe content. Similar to high temperature combustion synthesis, the products of low temperature combustion synthesis consist of TiC, Fe and a litter Fe2Ti. However, the amount of TiC is the greatest and the size of TiC particles is the smallest at 45wt% Fe content.
Using Gleeble-1500D thermal simulation equipment, the effect of Fe content on the low temperature combustion synthesis process of Fe-Ti-C system and microstructure features of the products were studied in this study. The results show that the ignition temperature of Fe-Ti-C system can be decreased greatly under the action of electric field and great thermal density. Moreover, the effect of Fe on the low temperature combustion synthesis process becomes greater with the increasing of Fe content. And the ignition temperature becomes higher, the delay time of ignition becomes shorter and the highest temperature becomes higher with the increasing of Fe content. Similar to high temperature combustion synthesis, the products of low temperature combustion synthesis consist of TiC, Fe and a litter Fe2Ti. However, the amount of TiC is the greatest and the size of TiC particles is the smallest at 45wt% Fe content.
2004, 33(2):166-170.
Abstract:
将碱液处理过的多孔钛浸泡在含有不同离子及离子浓度的3种过饱和钙化溶液中，均制得了多孔钛表面磷灰石涂层。所有涂层的钙磷比均小于羟基磷灰石的钙磷化学计量比。在SBF和ACS中形成的涂层的钙磷比与人骨中的钙磷比比较接近。在SCS和ACS中形成的涂层还含有磷酸八钙。过饱和度的增加可以引起磷灰石更快成核与生长。较小的过饱和度和Mg^2 离子的结晶生长抑制作用使SBF中形成了结晶细小且比较薄的涂层，不破坏多孔钛的孔隙结构。在SCS中形成的涂层厚度约70gm，使孔隙尺寸大大减小。在ACS中形成的涂层有孔隙被堵塞的现象。
将碱液处理过的多孔钛浸泡在含有不同离子及离子浓度的3种过饱和钙化溶液中，均制得了多孔钛表面磷灰石涂层。所有涂层的钙磷比均小于羟基磷灰石的钙磷化学计量比。在SBF和ACS中形成的涂层的钙磷比与人骨中的钙磷比比较接近。在SCS和ACS中形成的涂层还含有磷酸八钙。过饱和度的增加可以引起磷灰石更快成核与生长。较小的过饱和度和Mg^2 离子的结晶生长抑制作用使SBF中形成了结晶细小且比较薄的涂层，不破坏多孔钛的孔隙结构。在SCS中形成的涂层厚度约70gm，使孔隙尺寸大大减小。在ACS中形成的涂层有孔隙被堵塞的现象。
2004, 33(2):171-175.
Abstract:
研究了可热处理铸造Al-Si系合金的时效行为。发现合金的时效硬化曲线表现出不同的单、双峰硬化特征。透射电镜(TEM)、高分辨电镜(HRTEM)观察和差示扫描量热仪(DSC)分析证实，时效硬化的单、双峰现象与合金的时效析出序列密切相关，AlSiMg合金的GPⅡ区和亚稳定相的形成部分重叠交叉进行，造成了时效曲线上的硬度平台；在AlSiCu合金的时效过程中，GP区向亚稳定相的直接转变，造成了时效曲线上的单硬度峰。而A354和AlSiCuMg合金中GPⅡ区向亚稳相的转变有明显的时间间隔，使合金时效硬化曲线出现了双硬度峰现象。
研究了可热处理铸造Al-Si系合金的时效行为。发现合金的时效硬化曲线表现出不同的单、双峰硬化特征。透射电镜(TEM)、高分辨电镜(HRTEM)观察和差示扫描量热仪(DSC)分析证实，时效硬化的单、双峰现象与合金的时效析出序列密切相关，AlSiMg合金的GPⅡ区和亚稳定相的形成部分重叠交叉进行，造成了时效曲线上的硬度平台；在AlSiCu合金的时效过程中，GP区向亚稳定相的直接转变，造成了时效曲线上的单硬度峰。而A354和AlSiCuMg合金中GPⅡ区向亚稳相的转变有明显的时间间隔，使合金时效硬化曲线出现了双硬度峰现象。
2004, 33(2):176-178.
Abstract:
A photolithograph technology is used to fabricate patterned fine lead frame, and the factor of partial silver-plating is discussed. We find the pretreatment and electroplating technology is the key of plating layer quality: 1, current density can influence the roughness of silver plating surface, if it is 0.5 A/dm2, we can get the smooth silver plating; 2, electroplating time also plays an important role in controlling plating thickness, we can gain the even silver plating after 12 min-16 min plating.
A photolithograph technology is used to fabricate patterned fine lead frame, and the factor of partial silver-plating is discussed. We find the pretreatment and electroplating technology is the key of plating layer quality: 1, current density can influence the roughness of silver plating surface, if it is 0.5 A/dm2, we can get the smooth silver plating; 2, electroplating time also plays an important role in controlling plating thickness, we can gain the even silver plating after 12 min-16 min plating.
2004, 33(2):179-182.
Abstract:
Superfine copper powders can be used as the electronically conductive adhesives, ceramic materials and catalyst, and have shown a good application prospect instead of silver with copper in industry. The anti-oxidation nano-scale copper powders were prepared by using a protection-reduction technique from a copper ammonia complex solution, in which ascorbic acid (VC) was used as reducing agent, and polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) or polyacrylamide (PAA) were protection agents, and oleic acid was passivation agent. The obtained copper powders are homogeneous and stable in air. The reaction temperature and the value of n (protection agent): n (Cu) have a great influence on the particle size and shape. When the ratios of n (PVP),n (PVA) and n (PAA) to n (Cu) range from 0.03 to 0.1, 0.02 to 0.09 and 0.02 to 0.08 respectively, the obtained particles will be cuboids or non-spheroid. The reason can be attributed to the partial protection of polymer.
Superfine copper powders can be used as the electronically conductive adhesives, ceramic materials and catalyst, and have shown a good application prospect instead of silver with copper in industry. The anti-oxidation nano-scale copper powders were prepared by using a protection-reduction technique from a copper ammonia complex solution, in which ascorbic acid (VC) was used as reducing agent, and polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) or polyacrylamide (PAA) were protection agents, and oleic acid was passivation agent. The obtained copper powders are homogeneous and stable in air. The reaction temperature and the value of n (protection agent): n (Cu) have a great influence on the particle size and shape. When the ratios of n (PVP),n (PVA) and n (PAA) to n (Cu) range from 0.03 to 0.1, 0.02 to 0.09 and 0.02 to 0.08 respectively, the obtained particles will be cuboids or non-spheroid. The reason can be attributed to the partial protection of polymer.
2004, 33(2):183-186.
Abstract:
采用液相包裹法对Al2O3微粉进行稀土Y2O3表面改性，用挤压铸造法制备表面经稀土Y2O3改性的Al2O3／Al复合材料，并对复合材料的显微组织及界面进行观察和分析。结果表明：表面经稀土Y2O3改性的Al2O3微粉能均匀的分布于基体中，界面润湿性得以改善，复合材料组织更加均匀。拉伸性能测试表明：改性粉体对Al合金拉伸性能增强效果明显。对复合材料界面进行TEM，HREM及电子衍射分析表明，界面结合良好，界面处有Y2Al生成。EDAX分析表明界面相是钇、铝含量很高的物相；XRD图谱中也显示出Y2Al的衍射峰。
采用液相包裹法对Al2O3微粉进行稀土Y2O3表面改性，用挤压铸造法制备表面经稀土Y2O3改性的Al2O3／Al复合材料，并对复合材料的显微组织及界面进行观察和分析。结果表明：表面经稀土Y2O3改性的Al2O3微粉能均匀的分布于基体中，界面润湿性得以改善，复合材料组织更加均匀。拉伸性能测试表明：改性粉体对Al合金拉伸性能增强效果明显。对复合材料界面进行TEM，HREM及电子衍射分析表明，界面结合良好，界面处有Y2Al生成。EDAX分析表明界面相是钇、铝含量很高的物相；XRD图谱中也显示出Y2Al的衍射峰。
2004, 33(2):187-189.
Abstract:
Through corrosion weight-losing and polarization curve test, the corrosion-resistance properties of FVS0611, FVS0812, 6061, 2618, 2618+Sc, 2014 alloys under artificial seawater and oceanic condition have been investigated. It shows that FVS0611, FVS0812 and 6061 alloys prepared by RS/PM have a low corrosion while 2618, 2618+Sc and 2014 alloys has high corrosion. FVS0611, FVS0812 and 6061 alloys have obvious passivation. In the meantime, a phenomenon of passivation-corrosion-passivation occurs among them because residual process stress exists
Through corrosion weight-losing and polarization curve test, the corrosion-resistance properties of FVS0611, FVS0812, 6061, 2618, 2618+Sc, 2014 alloys under artificial seawater and oceanic condition have been investigated. It shows that FVS0611, FVS0812 and 6061 alloys prepared by RS/PM have a low corrosion while 2618, 2618+Sc and 2014 alloys has high corrosion. FVS0611, FVS0812 and 6061 alloys have obvious passivation. In the meantime, a phenomenon of passivation-corrosion-passivation occurs among them because residual process stress exists
2004, 33(2):190-192.
Abstract:
A nanoparticulate-reinforcing method of gold was presented in order to improve its hardness and hence the wearing quality. And the nanoparticulate-reinforced gold with tungsten was also preliminary investigated. During the high-frequency induction smelting of casting gold plates of 3 mm in thick and with nanotungsten encapsulated in, the hardness number of gold is enhanced by 20.5% for the mass fraction of nanotungsten of 0.12%. Through the analyses of the reinforcing results, it is shown that the further improvement for the dispersion degree of nanotungsten in gold is a key factor, and it is worthy of further studying to improve the smelting ambience of gold and to select some other stable nanoparticulates.
A nanoparticulate-reinforcing method of gold was presented in order to improve its hardness and hence the wearing quality. And the nanoparticulate-reinforced gold with tungsten was also preliminary investigated. During the high-frequency induction smelting of casting gold plates of 3 mm in thick and with nanotungsten encapsulated in, the hardness number of gold is enhanced by 20.5% for the mass fraction of nanotungsten of 0.12%. Through the analyses of the reinforcing results, it is shown that the further improvement for the dispersion degree of nanotungsten in gold is a key factor, and it is worthy of further studying to improve the smelting ambience of gold and to select some other stable nanoparticulates.
Tu Feng
,
Xia Zhengcai
,
Zhang Guoqing
,
Peng Gang
,
Li Zhongyi
,
Liu Jie
,
Liu Li
,
Xiong Caoshui
,
Xiong Yonghong
,
Yuan Songliu
2004, 33(2):193-195.
Abstract:
The effect of YSZ doping level on transport properties and magnetoresistance in La2/3Ca1/3MnO3 has been experimentally studied. The samples are prepared by a standard sol-gel method. Through the measurement of the electronic properties of samples we can draw a conclusion that for x < 2%, the dopant cause the metal-insulator transition shift to low temperature and increase the resistance of samples. Then with the increase of doping level further, the resistance decreases and the metal-insulator transition temperature increase. Meanwhile , the YSZ dopant can increase the LFMR, it's maximum at 1%.
The effect of YSZ doping level on transport properties and magnetoresistance in La2/3Ca1/3MnO3 has been experimentally studied. The samples are prepared by a standard sol-gel method. Through the measurement of the electronic properties of samples we can draw a conclusion that for x < 2%, the dopant cause the metal-insulator transition shift to low temperature and increase the resistance of samples. Then with the increase of doping level further, the resistance decreases and the metal-insulator transition temperature increase. Meanwhile , the YSZ dopant can increase the LFMR, it's maximum at 1%.
2004, 33(2):201-203.
Abstract:
实现了(TbDy)Fe2合金的电磁悬浮熔炼。采用红外测温、过程摄像、LECO图像分析仪、扫描电镜(SEM)以及电子探针等手段对(TbDy)Fe2合金在悬浮熔炼情况下的凝固特性、组织形成机理进行了分析研究。接近包晶成分该合金通过悬浮熔炼，熔体过热和快淬，凝固组织为基体相REFe2相，大量棒状REFe3相，富集于棒状REFe3相周围的大量富稀土相和少量存在于基体REFe2相中的富稀土相。这种现象的形成可以解释为该实验条件下，合金发生非平衡凝固，导致包晶REFe2相和初生REFe3相的耦合生长。包晶耦合生长和达到共晶反应温度所发生的共晶反应造成了这一现象。
实现了(TbDy)Fe2合金的电磁悬浮熔炼。采用红外测温、过程摄像、LECO图像分析仪、扫描电镜(SEM)以及电子探针等手段对(TbDy)Fe2合金在悬浮熔炼情况下的凝固特性、组织形成机理进行了分析研究。接近包晶成分该合金通过悬浮熔炼，熔体过热和快淬，凝固组织为基体相REFe2相，大量棒状REFe3相，富集于棒状REFe3相周围的大量富稀土相和少量存在于基体REFe2相中的富稀土相。这种现象的形成可以解释为该实验条件下，合金发生非平衡凝固，导致包晶REFe2相和初生REFe3相的耦合生长。包晶耦合生长和达到共晶反应温度所发生的共晶反应造成了这一现象。
2004, 33(2):204-206.
Abstract:
Using pulsed DC plasma chemical vapor deposition technology, the Ti(C, N) films on H13 steel were prepared under different CH4 atmospheres. The cross-sections of the Ti(C,N) films were investigated by SEM, and the elements in the film were characterized by XRD and XPS .The results show that addition of C to TiN film prevents the growth of TiN grains and development of column structure. The Ti(C, N) can be composed of two phases of TiN and phase TiC.
Using pulsed DC plasma chemical vapor deposition technology, the Ti(C, N) films on H13 steel were prepared under different CH4 atmospheres. The cross-sections of the Ti(C,N) films were investigated by SEM, and the elements in the film were characterized by XRD and XPS .The results show that addition of C to TiN film prevents the growth of TiN grains and development of column structure. The Ti(C, N) can be composed of two phases of TiN and phase TiC.
2004, 33(2):207-212.
Abstract:
Aluminum alloy matrix composites reinforced with single carbon or alumina and the two short fibers were fabricated by a performing squeeze-infiltrated method, respectively. The dry sliding friction and wear behavior of the aluminum alloy and its composites were investigated. The morphology of worn surface and subsurface was also observed and analyzed. The results show that carbon is of a self-lubrication in the composites in a degree. Wear rate of the hybrid composites reinforced with both alumina and carbon fibers is lower than that of unreinforced aluminum alloy, and composites reinforced with only carbon or alumina fibers. By comparison with mono-renforced aluminum alloy, the critical transition load from mild wear to severe wear of the composites reinforced with only alumina fiber is improved from the range of 147 N-196 N to 196 N-245 N. Moreover, the critical transition load of the hybrid composites reinforced with both alumina and carbon fibers is improved further to 245N-296N. The observations and analysis of worn surface and subsurface indicate that the reinforced fibers have no significant effect on wear mechanisms of aluminum alloy. The dominant mechanisms are abrasive and slight adhesion as well as delamination during mild wear stage. The subsurface consists of three regions: non-peeling delamination layer, microcracks formation and propagation zone, and unaffected zone. Whereas the dominant mechanisms are shifted to severe wear, and the non-peeling delamination layer is damaged during severe wear regime.
Aluminum alloy matrix composites reinforced with single carbon or alumina and the two short fibers were fabricated by a performing squeeze-infiltrated method, respectively. The dry sliding friction and wear behavior of the aluminum alloy and its composites were investigated. The morphology of worn surface and subsurface was also observed and analyzed. The results show that carbon is of a self-lubrication in the composites in a degree. Wear rate of the hybrid composites reinforced with both alumina and carbon fibers is lower than that of unreinforced aluminum alloy, and composites reinforced with only carbon or alumina fibers. By comparison with mono-renforced aluminum alloy, the critical transition load from mild wear to severe wear of the composites reinforced with only alumina fiber is improved from the range of 147 N-196 N to 196 N-245 N. Moreover, the critical transition load of the hybrid composites reinforced with both alumina and carbon fibers is improved further to 245N-296N. The observations and analysis of worn surface and subsurface indicate that the reinforced fibers have no significant effect on wear mechanisms of aluminum alloy. The dominant mechanisms are abrasive and slight adhesion as well as delamination during mild wear stage. The subsurface consists of three regions: non-peeling delamination layer, microcracks formation and propagation zone, and unaffected zone. Whereas the dominant mechanisms are shifted to severe wear, and the non-peeling delamination layer is damaged during severe wear regime.
2004, 33(2):213-217.
Abstract:
PW, BO, OP three series of binders containing ten different constituents and ten corresponding binder -powder mixtures were prepared. TGA-DTA thermal analysis was used to investigate binder and feedstock properties. The results show that in the binder system, organic polymer component and content have a great influence on the thermal properties of binder and feedstock such as binder melting point, decomposition temperature degradation curves. The thermal behavior can exactly determine the debinding way and process of the binders.
PW, BO, OP three series of binders containing ten different constituents and ten corresponding binder -powder mixtures were prepared. TGA-DTA thermal analysis was used to investigate binder and feedstock properties. The results show that in the binder system, organic polymer component and content have a great influence on the thermal properties of binder and feedstock such as binder melting point, decomposition temperature degradation curves. The thermal behavior can exactly determine the debinding way and process of the binders.
2004, 33(2):218-221.
Abstract:
通过OM，XRD，SEM和TEM等多种分析手段对Ti-25V-15Cr-2Al-0.2C阻燃β钛合金的微观组织和相组成进行了研究。结果表明，α和(Ti，V)C是β基体上的2种主要析出相，合金在高温长时间热暴露(540℃，100h)后会析出金属间化合物TiCr2相。此外，也有极少量α相在热暴露期间发生了短程有序化(SRO)转变。
通过OM，XRD，SEM和TEM等多种分析手段对Ti-25V-15Cr-2Al-0.2C阻燃β钛合金的微观组织和相组成进行了研究。结果表明，α和(Ti，V)C是β基体上的2种主要析出相，合金在高温长时间热暴露(540℃，100h)后会析出金属间化合物TiCr2相。此外，也有极少量α相在热暴露期间发生了短程有序化(SRO)转变。
2004, 33(2):222-224.
Abstract:
研究了pH值在1.0～1.5磷酸介质中,柠檬酸存在下,痕量钒对溴酸钾氧化对乙酰基偶氮胂的褪色反应及其动力学条件,建立了测定痕量钒的新方法.本法表观摩尔吸光系数εmax=2.64×106L·mol-1·cm-1,线性范围为0～10 ng·ml-1,检出限为1.41×10-11g·L-1.方法用于测定自来水、湖水、芹菜样中痕量钒(V),取得了令人满意的结果.
研究了pH值在1.0～1.5磷酸介质中,柠檬酸存在下,痕量钒对溴酸钾氧化对乙酰基偶氮胂的褪色反应及其动力学条件,建立了测定痕量钒的新方法.本法表观摩尔吸光系数εmax=2.64×106L·mol-1·cm-1,线性范围为0～10 ng·ml-1,检出限为1.41×10-11g·L-1.方法用于测定自来水、湖水、芹菜样中痕量钒(V),取得了令人满意的结果.
