Chang Hui , Zhou Lian , Zhang Tingjie
2007, 36(9):1505-1510.
Abstract:综述了近年来国内外学者在钛合金固态相变理论和实验研究方面的进展情况,介绍了几种钛合金固态相变的研究实验方法,并对钛合金中马氏体、硼、亚稳脚分解等相变动力学、晶体学以及组织的演变、形核生长等进行了总结和归纳。
Jia Wanming , Zhang Quanxiao , Bai Zhiguo , Ma Shaohua , Yao Dong , Wang Yingqi
2007, 36(9):1511-1516.
Abstract:In this paper, the progresses on manufacturing and precision forming techniques home and overseas have been introduced for exact shaped charge liners in detail. Some trends of advanced manufacturing techniques for heavy metal liners have been also discussed and predicted for the future. It is considered that the material of liners is key to improve the penetrating properties of shaped charges, and the forming technology plays an important role in the jets characters, then influences the penetration effect for shaped charge liners.
Shen Jun , Pei Xinfeng , Peng Guilin , Fu Hengzhi
2007, 36(9):1517-1522.
Abstract:The effects of inductor structure, the positions of solid/liquid interface and melt top, and different alloys on the melt shape in electromagnetic contactless shaping process have been simulated by FEM method in the present paper. It is found that the inductor with an oblique inside wall makes the melt form an ideal vertical periphery. The position variation of solid/liquid interface and melt top can change the melt shape obviously. The electrical current frequency and the material kind have hardly effects on the melt shape. The experiment results have good agreements with the simulation results. Finally, some bars and plates of Al alloy, TiAl intermetallics and superalloy are produced in an unidirectional control of their structures by the contactless forming process.
Yu Zhongliang , Zhao Yongqing , Zhou Lian , Sun Jun , Qu Henglei
2007, 36(9):1523-1526.
Abstract:研究了缺口对TC21合金在不同温度高周和低周疲劳强度的影响。疲劳试样为光滑和V型缺口(Kt=3)2种试样,疲劳载荷为应力控制,循环应力比为0.1,高周疲劳实验温度为315℃,低周疲劳实验温度为室温及400℃。结果表明,在循环应力较低,缺口根部未塑性变形时,缺口使疲劳强度明显降低。循环应力升高使缺口根部产生塑性变形时,缺口对疲劳强度影响降低,当循环应力升高使光滑试样失稳时,缺口试样的疲劳强度高于光滑试样的疲劳强度。断口的SEM分析表明,缺口试样的疲劳裂纹在缺口根部萌生,即使高周疲劳裂纹源也是多个。
Li Shuhua , Wang Fuchi , Tan Chengwen , Chen Zhiyong , Sun Zhi
2007, 36(9):1527-1529.
Abstract:Microstructural evolution of the adiabatic shear bands originated by the deformation of high strain for TA2 has been examined. Tests were performed using a specially designed stepped specimens in a Hopkinson bar. Upon completion of deformation, the region is cooled below half the temperature achieved during adiabatic heating for less than one millisecond. Microsturctural characterizations of shear bands were analysed using SEM, TEM and the TEM of high resolving power. No evidence of transition from a-Ti to another phases within the adiabatic shear bands could be found. However, the kinetics of boundary refinement processes were not taken into account in these studies with the distinctive characteristic of recrystallized microstructure. It is shown that there is no phase transformation in the TA2 adiabatic shear bands, which are composed of fine equiaxed grains. The dynamic recrystallization in the TA2 adiabatic shear bands was performed by the mixed mechanism of grain mechanical fragmentation, grain boundary transfer and subgrain roughen, and the recrystallization mechanism of progressive subgrain misorientation.
Shen Qianhong , Yang Hui , Gao Jiwei , Yang Jiegeng
2007, 36(9):1530-1533.
Abstract:采用浸渍提拉法依次在普通载玻片上制备PEDT/PSS(聚乙撑二氧噻吩(PEDT)掺杂聚苯乙烯磺酸盐(PSS))薄膜层和TiO2薄膜层,从而获得TiO2-PEDT/PSS双层复合膜。考察了PEDT/PSS涂膜液的组成、PEDT/PSS薄膜层厚度以及Ti02薄膜层厚度对TiO2-PEDT/PSS复合膜光催化活性的影响。发现PEDT/PSS溶液与正硅酸乙酯(TEOS)水解产物的体积比为10:1~15:1时,PEDT/PSS涂膜液性能最优,PEDT/PSS薄膜层的最佳厚度为2μm,TiO2薄膜层的最佳厚度在200nm左右。此外,还对复合膜光催化活性提高的机制进行了探讨。结果表明,由于PEDT/PSS的最低空余轨道的电位低于Ti02的导带电位,紫外光照下,TiO2中产生的光生电子注入到PEDT/PSS层,有效抑制了电子.空穴对的复合,增加了复合膜表面空穴的浓度,因此复合膜光催化活性比单一TiO2薄膜高。
Gao Zhiyong , Wu Bosen , Lu Xili , Tang Zhenyu
2007, 36(9):1534-1538.
Abstract:采用动态机械分析仪(DMA)、透射电镜(TEM)和示差扫描量热分析仪(DSC)等手段,系统地研究了时效处理对TiNi合金阻尼行为的影响规律及其微观机制。结果表明,第二相粒子对合金阻尼行为具有不同的影响。细小、弥散的Ti3Ni4相提高了TiNi合金相变过程中马氏体的阻尼值,粗片状的Ti3Ni4相对阻尼行为的影响较小。
Li Jianzhang , Zhang Litong , Cheng Laifei , Xu Yongdong , Li Douxing
2007, 36(9):1539-1544.
Abstract:在连续纤维增强陶瓷基复合材料中,界面调节脆性基体与脆性纤维之间匹配关系的功能以及自身特有的物理化学性质,决定着复合材料的整体综合效能。本研究从实践中发现界面区的存在,并尝试提出界面区的概念。界面区是具有一定厚度,含有两处界面(界面相/基体和界面相/纤维)和体相(界面相)的区域。采用透射电子显微技术从微结构的角度研究了3DC/SiC内界面区与裂纹的相互作用行为。TEM观察表明,由于裂纹偏斜/贯穿竞争随时空的推演,基体主裂纹会在界面区的多处位置产生单多重偏斜、裂纹尖端前方应力集中诱发脱粘和开裂、纳米尺度微裂纹桥连等相互作用,其发生的具体部位和方式由界面区内各种相关界面(或断裂)韧性共同决定。此外,结合影响因素的讨论,初步建立起3DC/SiC内基体裂纹与界面区相互作用的物理模型。
Liu Changjiu , Wang Huijing , Wu Huabin , Sun Dan
2007, 36(9):1545-1548.
Abstract:采用快速冷冻沉淀法制备出了非晶态纳米氢氧化镍。对制得材料样品进行了XRD,SEM,TEM,DSC和比表面积与孔径分析,将其制成MH-Ni电池正极材料进行充放电性能测试。结果表明:材料粉体为非品态,颗粒粒度为纳米级,类似球形。非晶纳米Ni(OH)2的热分解温度286.4℃低于常规球形Ni(OH)2的热分解温度333.8℃,同时具有较大得比表面积和孔径,分别为76.2089m^2·g^-1和37.7nm。与普通β-Ni(OH)2相比较,非晶态纳米氢氧化镍电极充电电压低,放电电压平台时间长,且高达1.258V,放电比容量为349.85mAh/g,具有较好的循环性能,20次循环后其容量衰减仅为1.28%。
Wen Zhixun , Gou Wenxuan , Yue Zhufeng
2007, 36(9):1549-1553.
Abstract:采用紧凑拉伸(CT)试样研究了3种不同温度(950,850,760℃)和3种不同晶体取向([001],[011],[111])下镍基单晶合金DD3的断裂特征,采用光学显微镜和扫描电子显微镜观察分析了裂纹扩展路径及断口形貌。采用率相关晶体滑移有限元程序对试件裂纹尖端三维分切应力场结构、裂纹启裂和扩展机制以及滑移系激活规律进行了模拟计算分析。结果表明:晶体取向和环境温度对裂纹启裂和扩展以及断裂强度和断裂形式有较大的影响,低温下裂纹扩展沿着特定的滑移带方向,与裂纹平面成一斜角,[001]裂纹取向下为45°,[011]裂纹取向下为53.7°,[111]裂纹取向下为90°,这使得宏观上裂纹扩展路径呈现Z字形外观。而温度较高时,发生的Ⅰ型裂纹扩展与加载方向垂直。并且随着温度的升高,断裂形式逐步由脆性断裂转化为韧性断裂。
Zhang Wei , Li Ning , Wen Yuhua , Huang Shuke
2007, 36(9):1554-1557.
Abstract:研究了等通道转角挤压后时效处理对FeMnSiCrNiC合金碳化物的析出和形状记忆效应的影响。结果发现,挤压态合金经973K时效处理150min后,平均晶粒尺寸约10btm,同时晶内和晶界处析出大量碳化物。碳化物析出在回复完成前即开始,挤压产生的大量缺陷降低了碳化物析出的激活能,促进了碳化物析出。细晶强化和碳化物析出强化的共同作用显著提高了合金的基体强度,抑制预变形中的塑性变形,使更多的变形由应力诱发马氏体承担。因此,合金形状回复率达到89.4%(预变形4.33%时),比固溶态高120%,比直接时效高40%。
2007, 36(9):1558-1561.
Abstract:使用“固体与分子经验电子理论”(EET)分别计算了纯Mo,W原子的价电子结构表电子结构,使用“键距差法”(BLD)分别对纯Mo,W及Mo.30W合金进行了计算,按照“固体与分子经验电子理论”基本思想提出了杂阶数目多则材料抗腐蚀性高的观点。结果表明:Mo-30W合金的耐液态锌的腐蚀性、弹性、塑性、强度等指标远高于纯Mo,W材料,更具有工业价值。
Long Zhaohui , Liao Shuzhi , Wu Xiaozan , Gui Xuchun , Deng Zhihong , Zhang Bangwei
2007, 36(9):1562-1565.
Abstract:用改进分析型嵌入原子模型(MAEAM)计算了Mo-Pd二元合金在2个典型温度的边际固溶度。在淬火温度为1473K时,Pd在Mo(a相区)中的边际固溶度为0.6%(原子分数,下同):Mo在Pd(声相区)中的边际固溶度为26.8%;在包晶温度2028K附近,Pd在Mo(a相区)中的边际固溶度为1.1%;Mo在Pd(声相区)中的边际固溶度为29.5%。计算结果与已有理论和实验结果大体上是吻合的。
Zhang Qi , Li Tingjü , Wang Tongmin , Jin Junze
2007, 36(9):1566-1569.
Abstract:Static simulation experiment is done for the Sn-3.5%Pb alloy of low-melting point to verify the effect of inner traveling magnetic field on the solidification microstructure of hollow tubular billet by continuous casting. The results show that the traveling magnetic field can provoke the circulation flow in the vertical section of molten metal, reduce the temperature gradient of solidification front and the cooling rate of molten metal, facilitate the transition from columnar to equiaxed structure, and refine the grains. So, the solidification microstructure of hollow tubular billet by continuous casting.was improved by the inner traveling magnetic field.
2007, 36(9):1574-1577.
Abstract:采用柠檬酸溶胶.凝胶法成功地合成了Sm^3+,Li^+掺杂的SrZn02系列荧光粉。用XRD,PL等手段研究了样品的物相结构和光致发光性能。SrZnO2:Sm^3+样品的激发主峰位于413nm附近,能有效地被近紫外光激发;最大发射峰在607nm。在SrZnO2:Sm^3+荧光体中共掺杂Li^+后,样品的晶化程度增加,晶格稍膨胀;在发光性能上,降低了基质的激发效率,也削弱了Sm^3+-O^2-的电荷转移激发强度,但是增强了样品的橙红光发射。研究显示,SrZnO2:Sm^3+,Li^+荧光体可望成为一种与InGaN管芯匹配的LED用红色荧光粉。
Zhang Jianjun , Wang Yongxin , Chen Zheng , Liu Bing
2007, 36(9):1578-1583.
Abstract:基于Thomas—Fermi模型,系统定量地计算研究了在电场作用下Al6CuMg4准晶相对于Al-Cu-Mg固溶体及普通化合物的自由能和吉氏自由能的变化趋势。结果表明:Al6CuMg。准晶相、Al2CuMg及Al-Cu-Mg固溶体的自由能与吉氏自由能,均随着电场强度的增大而升高。正电场作用要高于负电场作用,但差距不大。Al6CuMg。准晶相的自由能与吉氏自由能相对于固溶体对电场的变化更为敏感,随着电场的升高,Al6CuMg4与固溶体间的自由能与吉氏自由能的差值迅速增加。电场作用使得准晶相的不稳定性增加,Al2CuMg的稳定性显著高于Al6CuMg4的电场稳定性。对于Al-Cu-Mg固溶体,随着Mg含量的增加,合金对电场的敏感性增强,但增大幅度要远远小于化合物与准晶相的增大幅度。
Ma Yilong , Liu Ying , Zhang Ran , Li Jun , Gao Shengji , Tu Mingjing
2007, 36(9):1584-1587.
Abstract:采用熔体快淬结合静态晶化法,制备出高性能、低温度系数双相纳米晶复合永磁材料(NdDy)11.5Fe81.4Nb1B6.1及(NdDy)11.5Fe76.4Nb1Co5B6.1,并着重研究了Co的添加对复合添加Dy,Nb磁体的磁性能、微观结构以及高温稳定性的影响。结果表明:随着Co含量的增加,内禀矫顽力先减小后增大,剩磁则先增加后减小,合金晶粒逐步细化;Co的添加并没有降低磁体的磁通不可逆损失,当Co含量大于5%(原子分数,下同)时,磁通不可逆损失大幅度提高。
2007, 36(9):1588-1591.
Abstract:对LF2铝合金搅拌摩擦焊接接头的静载力学行为和疲劳特性进行了研究,建立了焊接接头的孓Ⅳ曲线。力学实验结果表明:LF2铝合金搅拌摩擦焊接接头的最高抗拉强度为252.8MPa,是母材抗拉强度的95.4%。疲劳实验结果表明:搅拌摩擦焊接接头表现出良好的疲劳性能,疲劳寿命N=10^5次的疲劳强度为59~65MPa。显微组织分析表明:搅拌摩擦焊接接头具有细小的等轴晶粒和狭窄的热影响区,阻碍了滑移带的形成和裂纹的扩展,从而提高了接头的疲劳性能。疲劳断口分析显示:随着驻留滑移带的扩展逐渐萌生裂纹,在交变应力作用下最终导致失效。
Li Rong , Zhou Shangqi , Liang Guoming , Sun Yuyang , Liu Shouping , Luo Xiaoling , Wan Yan
2007, 36(9):1592-1596.
Abstract:利用电荷自洽离散变分Xa(SCC—DV-Xa)方法计算了吸热型金属合金化对钒基贮氢材料性能的影响。结果表明:在V54H64中加入吸热型金属Cr,Mn,Fe,Co,Ni后,随着原子序数的增加,V51M2H64中H的净电荷逐渐增加,V的净电荷逐渐减小;氢化物V51M2H64中V-H之间的离子性相互作用逐渐减弱,共价性相互作用逐渐增强。材料放氢的平衡压力与其费米能有很好的一致关系,加入吸热型金属后,氢化物V51M12H64中费米能增加,氢化物更不稳定,从而改善材料的吸放氢性能。
Wang Xuemin , Zeng Xiaoqin , Wu Guosong , Yao Shoushan
2007, 36(9):1597-1600.
Abstract:研究了AZ31镁合金在钇离子剂量为5×10^16,1×10^17及5×10^17ions/cm^2注入条件下的氧化性能。纯氧气氛、500℃下的氧化实验结果表明,钇离子注入能提高AZ31镁合金的抗氧化性能,而且随着注入剂量的增大,合金表面抗氧化性能提高越大。俄歇电子能谱(AES)和X光电子能谱(XPS)分析表明:钇离子注入以后,在镁合金表面形成了具有双层结构的氧化层,外层主要由MgO组成,而内层主要由Y2O3,MgO构成。这一新形成的氧化层有利于提高AZ31镁合金的抗氧化性能。
Zhang Jinling , Wang Shebin , Wei Yinghui , Zhang Junyuan , Li Mingzhao , Xu Bingshe
2007, 36(9):1601-1604.
Abstract:在真空Ar气氛中熔炼AZ91镁合金,测定了不同精炼温度下Mg元素的蒸发速率。结果表明,随着精炼温度的升高,Mg元素的蒸发量增大。通过计算可知,Mg的蒸气压是Al的10^9倍,是Zn的46倍,因此主要是Mg的蒸发而导致合金其他元素含量升高。XRD分析表明,蒸发物是Mg元素。结合Mg元素的蒸发机制,在该试验条件下推导出Mg元素蒸发率的计算公式以及Mg元素的表观传质系数、蒸发率与精炼温度的关系,计算得出Mg元素蒸发率为0.86×10^-3-1.35×10^3g/cm^2·s,Mg元素的表观传质系数在2×10^-5-24×10^-5cm/s范围内。
Hou Xueling , Kong Junfeng , Li Shitao , Zhou Bangxin , Ni Jiansen , Xu Hui , Zhang Shaojie
2007, 36(9):1605-1607.
Abstract:为了解决Gd5Si2Ge2磁制冷合金居里点低,制冷温区狭窄问题,采用合金化的方法,利用添加元素Sn代替Si或Ge,提高了Gd5Si1.9Ge2Sn0.1材料的居里温度,同时保持工质材料Gd5Si2Ge2的巨磁热效应,并相对于Gd5Si2Ge2合金的制冷温区有了很大的拓展。
Ouyang Hongwu , Yu Wentao , Chen Xin , He Shiwen , Huang Jinsong
2007, 36(9):1608-1612.
Abstract:利用“球化效应”,在SLS设备上探索将异形Ti粉转化为高性能球形粉末的可行途径。通过系统地改变激光功率、扫描速度,以及选取合适的激光扫描间距,探明了形成“球化效应”的工艺条件,并在激光功率为600W,扫描速度为30mm/s时,获得了较为理想的球形Ti粉。通过对球化过程进行理论分析,得出了选取激光扫描制备球形Ti粉工艺参数的准则。
Xin Shewei , Zhao Yongqing , Zheng Weidong , Wu Huan , Yang Haiying , Li Qian
2007, 36(9):1613-1616.
Abstract:Two Ti-V-Cr system burn-resistant titanium alloys of Ti-25V-15Cr-0.2Si and Ti-25V-15Cr-2Al-0.2Si were prepared. Their creep, thermal stability properties and microstructure were tested under different conditions. The result shows that Al strengthened the roomtemperature mechanical properties and reduced the creep and thermal stability properties of Ti-V-Cr system burn-resistance alloys. The microstructures of two alloys only contained a phase and Ti5Si3 phase under the experiment condition, other transition phases and intermetallic compounds were not found. During creep and thermal exposure processes, the decrease of structure stability and much more precipitated phases are attributed to the effect of alloying element Al which caused the reduction of thermal stability and creep properties of Ti-V-Cr burn resistant titanium alloy.
Yuan Xinjian , Sheng Guangmin , Qin Bin , Huang Wenzhan
2007, 36(9):1617-1622.
Abstract:采用纯镍箔作中间过渡层,在脉冲加压扩散连接工艺下,对TA17钛合金与0Cr18Ni9Ti不锈钢进行了连接试验,并测定了接头的拉伸强度。结果表明:采用镍箔作中间过渡金属的脉冲加压扩散连接,实现了钛合金与不锈钢的高效良好连接,接头抗拉强度达到了334MPa。采用金相显微镜和扫描电镜,对拉伸断口形貌进行了观察和分析;利用能谱仪(EDS)测定了拉伸断口各区域内的微区成分;并对拉伸断口进行了剥层试验。结果表明:拉伸断裂发生在Ni-Fe和Ni—Ti之间,Ni-Fe和Ni—Ti区均承载拉伸力,中间层Ni的存在成功地阻止了Fe与Ti之间的互扩散。
2007, 36(9):1623-1627.
Abstract:Ti5Si3-TiCo-Ti2Co multiphase intermetallic alloy with wear resistant has been fabricated by laser melt deposition process. The microstructure of intermetallic alloys is characterized by OM, SEM, XRD and EDS and the wear properties are evaluated in the room-temperature dry sliding wear conditions and the wear mechanism is discussed. It is found that the Ti5Si3-TiCo-Ti2Co multiphase intermetallic alloy has an excellent wear resistance under room-temperature dry sliding wear conditions. The wear mass loss increases very slowly, and the wear mass loss rate increases first then decreases with wear time increasing due to the high hardness of Ti5Si3, and the abnormal yield strength of intermetallics with temperature and the formation of smearing-layer on the worn surface.
Huang Lanping , Chen Kanghua , Li Song , Song Min
2007, 36(9):1628-1633.
Abstract:研究了高温预析出对Al-Zn—Mg—Cu系7055合金的应力腐蚀、晶间腐蚀和剥蚀行为以及时效硬化的影响,并通过对预析出/时效组织的透射电镜观察,阐述了预析出对7055合金各种腐蚀行为和时效硬化的影响。组织观察及腐蚀性能和力学性能测试结果表明:高温预析出处理可使7055合金抗应力腐蚀性能得到明显改善,合金应力腐蚀开裂界限应力强度因子局KISCC由7.4MPa·m^1/2提高至9.8MPa·m^1/2,合金抗拉强度仍能保持在680MPa左右。经高温预析出处理后的7055合金晶间腐蚀、剥蚀敏感性降低,7055合金的剥蚀等级由EC降为EA-。同时,高温预析出处理使晶界析出相粗化显著、离散度增大,晶界平衡析出相的Cu含量为60.18at%,且晶界析出相Cu含量提高。
Li Hai , Wang Zhixiu , Zheng Ziqiao
2007, 36(9):1634-1638.
Abstract:采用常规拉伸和慢应变速率拉伸方法测试了Al-9.88Zn-2.40Mg-2.32Cu-0.12Zr铝合金在T6,RRA及T73时效状态下的力学性能和抗应力腐蚀性能,并通过SEM和TEM观察了慢应变速率拉伸断口形貌及析出相特征。TEM结果表明,T6,RRA和T73时效状态的晶内析出相分别以GP区+η'相、η'相+η相、η相为主,并且晶内和晶界析出相尺寸以及晶界PFZ宽度依次增大:同时晶界析出相逐渐由长条状连续分布逐渐转变成球状不连续分布。这些微观组织特点使得3种时效状态下实验合金具有不同应力腐蚀开裂倾向、常规拉伸性能和断口形貌特征。
Yin Zhoulan , Zhong Shengkui , Wang Zhixing , Chen Qiyuan
2007, 36(9):1639-1643.
Abstract:通过碳热还原法合成了锂离子电池正极材料Li3V2(PO4)3,考察了不同合成温度、时间对产物晶形结构、形貌和电化学性能的影响。结果表明,当合成温度、时间分别为800℃,20h时,所合成的样品属于单斜晶系,且粒度大小分布比较均匀,该材料以0.2C充放电,其首次放电容量为120mAh·g^-1,循环30次后其比容量达108mAh·g^-1。
He Yushi , Liao Xiaozhen , Ma Zifeng , Yuan Xianxia , Wang Baofeng , Jiang Yi
2007, 36(9):1644-1648.
Abstract:采用高温固相碳热还原法(CTR,Carbothermal Reduction)合成了LiFePO4/C复合正极材料。采用XRD,SEM以及BET等方法对产物进行表征。结果表明,所得LiFeP04/C材料有着单一的橄榄石型晶体结构。750℃下制备产物的BET比表面积为39.7002m^2/g。利用恒流充放电,循环伏安法(CV),电化学阻抗谱(EIS)等电化学手段研究了LiFePO4/C材料的电化学性质。结果表明:750℃下制备的LiFePO4/C复合材料在25℃工作温度下,有着优异的循环稳定性和大倍率充放电性能,使用850ma/g(5C)的电流密度对电池充放电90次后,电池放电比容量仍能保持11lmAh/g。在55℃工作温度下1C充放电倍率时,首次和第90次循环的放电比容量分别为14513mAh/g和142.9mAh/g。
Hou Guangya , Jin Zhihao , Zheng Xiaohui , Qian Junmin
2007, 36(9):1649-1652.
Abstract:使用Ca(NO3)2-P2O5乙醇溶液体系制备纳米羟基磷灰石,研究了在该体系中水浴温度、煅烧温度、陈化时间等因素对粉体的相成分,粒度和结晶度的影响。结果表明:水浴温度低,合成的粉体粒度小(约20nm),颗粒均匀且具有良好的分散性,但是结晶度较低;陈化后导致粉体粒度变大,结晶度增加;随着煅烧温度的升高,粉体的结晶度增加,600℃时可以得到结晶高的单一的羟基磷灰石粉体。在800℃煅烧时,羟基磷灰石发生部分分解。
Zhai Yongqing , Liu Yuanhong , Li Change , Zhang Yue
2007, 36(9):1657-1660.
Abstract:采用微波法快速合成了Y2O2S:Tb绿色荧光粉。用X射线衍射(XRD)仪、扫描电镜(SEM)、荧光分光光度计等对合成产物的相结构、形貌、以及发光特性进行了研究。结果表明:材料的晶体结构为六方晶系,与Y2O2S相同。颗粒的形貌为类球形,分散性很好,平均晶粒尺寸在300nm左右。发射光谱由384,418,439,460,475,498,547,590,624nm等一系列窄带发射峰组成,归属于Tb^3+从^5D3,^5D4到^7FJ(J=0~6)的跃迁。研究发现Tb的掺杂浓度对样品的发射光谱有着很重要的影响,当其浓度为0.5%(摩尔分数,下同)时,^5D3→^7FJ的蓝光发射发生猝灭,当其浓度为9%时,^5D4→^7FJ的绿光发射发生猝灭。
Cheng Jikuan , Gao Jiqiang , Liu Junlin , Jiang Xian , Yang Jianfeng , Qiao Guanjun
2007, 36(9):1661-1664.
Abstract:研究了用物理气相传输(PVT)法制备SiC单晶的过程中附加碳源对晶体生长速度及缺陷的影响,并将活性炭与SiC粉末一起加入到石墨坩埚中进行晶体生长。用XRD分别测定了晶体生长前后坩埚与活性炭的石墨化度,并用光学显微镜观察了晶体中的缺陷。结果表明,随晶体生长过程的进行石墨坩埚的活性降低,直接导致晶体生长速度减慢,并使籽晶表面Si液相形成的可能性增大,与Si液相相关的缺陷增多。活性炭的加入给生长过程提供了充足的碳源,提高了晶体的生长速度,并抑制了籽晶表面Si液相的形成,从而降低了与Si液相相关缺陷出现的几率。
2007, 36(9):1665-1667.
Abstract:采用搅拌球磨法制备了纳米复相Nd2Fe14B/a—Fe永磁合金。借助X射线衍射(XRD)、差示扫描量热法(DSC)、透射电子显微镜(TEM)等分析方法研究了不同球磨时间及晶化处理温度对合金微观组织和磁性能的影响规律。结果表明:随球磨时间的延长,Nd2Fel4B相及a-Fe相的晶粒尺寸迅速减小,球磨5h后粉末由非晶相和晶粒尺寸约为10nm的a-Fe相组成,当晶化处理温度为650℃,保温时间为30min时,两相的晶粒尺寸比较细小,此时磁性能最好,达到Br=1.06T,Hci=347kA/m,(BH)m=142kJ/m^3。
Wu Xueqing , Ma Mo , Tan Chaogui , Liu Xuebin , Lin Jianguo
2007, 36(9):1668-1671.
Abstract:采用单辊甩带法制备出完全非晶态的Al88Ni6La6薄带,并用X射线衍射(XRD)仪和示差扫描量热计(Dsc)对该非晶薄带的非晶特性及其晶化过程进行了研究。该非晶薄带的晶化过程分为两步,其晶化温度约为239℃和332℃。在0.01mol/L NaCl溶液中对完全非晶态的A188Ni6La6试样及其部分晶化和完全晶化试样的电化学腐蚀行为进行了研究。结果表明,部分晶化的试样表现出最佳抗电化学腐蚀性能,而经过完全晶化的试样,其抗腐蚀性能明显下降。
Li Qian , Wu Zhu , Lu Xionggang , Zhou Guozhi , Xu Kuangdi
2007, 36(9):1672-1676.
Abstract:The Mg-based hydrogen storage composites have been successfully prepared by mechanochemical synthesis using Ti0.32Cr0.35V0.07Fe0.26 and Ni as additives. The hydrogen sorption-desorption characteristics were mensurated by an isovolumetric method, and the structures and constitutes, and the surface and body properties were investigated by XRD, SEM, TEM, GC and XPS, respectively. The correlations of the milling time and alloy components with the structure and hydrogen sorption-desorption property were elucidated, then the hydrogen sorption-desorption mechanism was discussed. The results indicate that the hydrogen sorption-desorption temperature decreased and the kinetic properties are improved because the fine Ti0.32Cr0.35V0.07Fe0.26 and Ni particles covering magnesium matrix act as the catalytic phases to produce a significant amount of nanoparticles in favor of the decrease of temperatures and the increase of speed for hydrogen sorption-desorption.
Wei Zhiqiang , Xia Tiandong , Jiang Jinlong , Shen Jie , Xu Yangtao , Zhang Penglin , Yan Pengxun
2007, 36(9):1677-1680.
Abstract:采用阳极弧放电等离子体法成功制备了银纳米粉体,并利用X射线衍射(XRD)、透射电子显微镜(TEM)和选区电子衍射(SAED)对样品的形貌、晶体结构、粒度及其分布进行性能表征。利用静态表面吸附仪测试样品对N2的吸附-脱附等温线,依据BJH理论模型分析样品的孔结构;利用BET吸附公式计算出样品的比表面积。结果表明:所制备的银纳米粉末的晶体结构与相应的块体材料基本相同,为fcc结构,其粒度主要分布在10~50nm,平均粒度为26nm,比表面积为23.81m^2/g,呈规则的类球形分布。
Zhang Yuejü , Li Xiaojie , Yan Honghao , Liu Kaixin , Qu Yandong , Wang Xiaohong
2007, 36(9):1681-1684.
Abstract:改进爆炸实验装置,并利用该装置实施了预热爆炸压实实验。以商业ITO纳米陶瓷粉末为原料,通过压力机将粉末压实到大约50%理论密度的初始压坯,选择预热温度为800℃以上进行爆炸压实,从而获得了致密且晶粒在纳米量级的良好烧结体。结果表明:预热爆炸烧结体微观组织结构均匀,晶粒尺寸分布在200nm左右,且将烧结体在扫描电镜上放大到100,000倍时仍未发现明显孔洞和微裂纹等缺陷。认为宏观塑性变形和晶粒长大是导致良好烧结的2个主要机制。
2007, 36(9):1685-1688.
Abstract:从Pd—C催化剂废料回收Pd(N03)2,然后在SDS/Brij30/H20体系O/W微乳液中制备纳米钯。结果表明:制备的钯纳米粒子的粒度在5-200nm之间:使用该体系不需外加还原剂,可直接利用非离子表面活性剂Brij30作为还原剂,简化后续单元操作。并初步探讨了SDS/Brij30/H2O体系O/W微乳液中纳米钯的制备机制。
Li Mingzhao , Zhang Junyuan , Wang Xiaomin , Wang Shebin , Xu Bingshe
2007, 36(9):1689-1692.
Abstract:In the process of vacuum melting AZ31 magnesium alloy, Nb powder and Mg-Nd intermediate alloy were added, respectively. The composition of inclusion and absorptivity of Nd in magnesium alloy were measured. The microstructure was observed, the precipitating phases were identified, and the approaches of increasing the mechanical properties of magnesium alloy were dicussed. The results show that amount of inclusion was decreased under vacuum condition. The absorptivity of Nd upon adding Mg-Nd intermediate alloy was higher than that upon adding Nd powder, simultaneously, new phases NdAl2 and Mg12Nd were formed, which fined grains and improved the mechanical properties of the alloy.
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