Volume 35,Issue 3,2006 Table of Contents
2006, 35(3):337-339.
Abstract:
High performance NdxFe90.5-x Zr3.0B6.5(x=8.5~11.5)ribbons were produced by arc melt spinning and then annealing.It is found that a proper amount of Nd addition can obviously optimize the magnetic properties of the samples.The energy product of NdxFe90.5-xZr3.0B6.5 ribbons is increased from 75 kJ/m3 for x=8.5 to 114 kJ/m3 for x=10.5 which is closed to that of America MQP-B magnets.In addition,it can be seen that Zr dopants can significantly improve the magnetic properties of the ribbons.
High performance NdxFe90.5-x Zr3.0B6.5(x=8.5~11.5)ribbons were produced by arc melt spinning and then annealing.It is found that a proper amount of Nd addition can obviously optimize the magnetic properties of the samples.The energy product of NdxFe90.5-xZr3.0B6.5 ribbons is increased from 75 kJ/m3 for x=8.5 to 114 kJ/m3 for x=10.5 which is closed to that of America MQP-B magnets.In addition,it can be seen that Zr dopants can significantly improve the magnetic properties of the ribbons.
2006, 35(3):340-342.
Abstract:
The corrosion behavior of sintered NdFeB in nitric acid hydrochloric acid,vitriol,phosphate and oxalic acid was studied.Potentiodynamic polarization curves and corrosion rate of sintered NdFeB in various solutions were tested.The surface morphology of sintered NdFeB corroded were investigated by means of SEM and AFM.The results indicate that corrosion of sintered NdFeB in hydrochloric acid and vitriol is most serious among all acid,and sintered NdFeB is passivated in phoshate and oxalic acid.The brim of sintered NdFeB is corroded rather seriously and the micro dimension was destroyed greatly in nitric acid.Every surface of magnet corroded by above acid becomes coarse.
The corrosion behavior of sintered NdFeB in nitric acid hydrochloric acid,vitriol,phosphate and oxalic acid was studied.Potentiodynamic polarization curves and corrosion rate of sintered NdFeB in various solutions were tested.The surface morphology of sintered NdFeB corroded were investigated by means of SEM and AFM.The results indicate that corrosion of sintered NdFeB in hydrochloric acid and vitriol is most serious among all acid,and sintered NdFeB is passivated in phoshate and oxalic acid.The brim of sintered NdFeB is corroded rather seriously and the micro dimension was destroyed greatly in nitric acid.Every surface of magnet corroded by above acid becomes coarse.
2006, 35(3):343-347.
Abstract:
测量了La0.67-xSmxSr0.33MnO3（x=0.40,0.50,0.60）体系的M-T曲线，p-T曲线和MR-T曲线。实验结果表明：x=0．40时，样品为长程铁磁有序；x=0．50时，样品为自旋团簇玻璃态；x=0．60时，样品在低温时表现为反铁磁状态。高掺杂（垆0．60）样品的输运行为发生异常，在瓦附近发生绝缘体．金属相变后，又发生金属．绝缘体相变的现象，这在ABO3结构中很少出现。体系的磁电行为变化取决于掺杂引起的额外磁性和晶格畸变效应。
测量了La0.67-xSmxSr0.33MnO3（x=0.40,0.50,0.60）体系的M-T曲线，p-T曲线和MR-T曲线。实验结果表明：x=0．40时，样品为长程铁磁有序；x=0．50时，样品为自旋团簇玻璃态；x=0．60时，样品在低温时表现为反铁磁状态。高掺杂（垆0．60）样品的输运行为发生异常，在瓦附近发生绝缘体．金属相变后，又发生金属．绝缘体相变的现象，这在ABO3结构中很少出现。体系的磁电行为变化取决于掺杂引起的额外磁性和晶格畸变效应。
4 Study of Defects and Electron Densities in TiAl Alloy Doped with V and Ag by Positron Annihilation
2006, 35(3):348-351.
Abstract:
Positron lifetime spectra of Ti50Al50, Ti50Al48V2, Ti50Al48Ag2 alloys and annealed Ti, Al, Ag, V metals were measured. The electron densities in the bulk and defects of the alloys were calculated by positron lifetime parameters. The poor ductility of binary TiAI alloy is related to low free electron densities in the bulk and the grain boundaries of the alloy. When V are added into Ti-rich TiAI alloy, V atoms will provide more free electrons than both Al and Ti atoms to participate in metallic bonds, thus increasing the electron densities in the bulk and the grain boundary simultaneously. Ag additions appear to have an effect similar to V additions. Both V and Ag are benefit elements in enhancing the ductility of TiAl alloys.
Positron lifetime spectra of Ti50Al50, Ti50Al48V2, Ti50Al48Ag2 alloys and annealed Ti, Al, Ag, V metals were measured. The electron densities in the bulk and defects of the alloys were calculated by positron lifetime parameters. The poor ductility of binary TiAI alloy is related to low free electron densities in the bulk and the grain boundaries of the alloy. When V are added into Ti-rich TiAI alloy, V atoms will provide more free electrons than both Al and Ti atoms to participate in metallic bonds, thus increasing the electron densities in the bulk and the grain boundary simultaneously. Ag additions appear to have an effect similar to V additions. Both V and Ag are benefit elements in enhancing the ductility of TiAl alloys.
2006, 35(3):352-356.
Abstract:
Investigations on the ordering and atom clustering in aged binary Al-Li alloy have been carried out by computer simulation.The long range order parameter(lro.)and composition deviation order parameter were calculated from single-site occupation probabilities of Li atom.The results show that as the composition of the alloy increases from metastable region to instable region in the phase diagram ordering occurs faster than atom clustering gradually and the incubation period of the phase transformation is shortened.
Investigations on the ordering and atom clustering in aged binary Al-Li alloy have been carried out by computer simulation.The long range order parameter(lro.)and composition deviation order parameter were calculated from single-site occupation probabilities of Li atom.The results show that as the composition of the alloy increases from metastable region to instable region in the phase diagram ordering occurs faster than atom clustering gradually and the incubation period of the phase transformation is shortened.
2006, 35(3):357-362.
Abstract:
研究了在模拟燃烧气氛中的高温氧化对Ti-48Al-2Cr-2Nb（at％）合金的高温拉伸性能的影响以及拉伸变形时氧化层及其影响层的变形特征。研究发现：在1173K模拟燃烧气氛中的高温氧化显著降低了该合金在1073K的总延伸率（J），屈服强度（σ0.2）和最大拉伸强度（UTS）。高温拉伸性能的降低与氧化层及其影响层的生长速率和结构关系密切。高温拉伸时，该合金氧化层及其影响层的破坏主要集中在3．5％到7．1％的应变范围内，其破坏形式主要表现为垂直于载荷方向的裂纹、断裂和剥离。分析认为，在1173K模拟燃烧气氛中的高温氧化对Ti-48Al-2Cr-2Nb合金的高温拉伸性能的影响途径主要有如下3个方面：①氧化层及其影响层的形成引起了邻近基体合金的成分发生改变；②氧化层及其影响层的早期破坏增加了它们与基体界面上的缺陷并促进了裂纹的萌生。③长时间的高温氧化引起了Ti-48Al-2Cr-2Nb合金内部显微组织发生改变。
研究了在模拟燃烧气氛中的高温氧化对Ti-48Al-2Cr-2Nb（at％）合金的高温拉伸性能的影响以及拉伸变形时氧化层及其影响层的变形特征。研究发现：在1173K模拟燃烧气氛中的高温氧化显著降低了该合金在1073K的总延伸率（J），屈服强度（σ0.2）和最大拉伸强度（UTS）。高温拉伸性能的降低与氧化层及其影响层的生长速率和结构关系密切。高温拉伸时，该合金氧化层及其影响层的破坏主要集中在3．5％到7．1％的应变范围内，其破坏形式主要表现为垂直于载荷方向的裂纹、断裂和剥离。分析认为，在1173K模拟燃烧气氛中的高温氧化对Ti-48Al-2Cr-2Nb合金的高温拉伸性能的影响途径主要有如下3个方面：①氧化层及其影响层的形成引起了邻近基体合金的成分发生改变；②氧化层及其影响层的早期破坏增加了它们与基体界面上的缺陷并促进了裂纹的萌生。③长时间的高温氧化引起了Ti-48Al-2Cr-2Nb合金内部显微组织发生改变。
2006, 35(3):363-366.
Abstract:
利用光学显微镜（OM）和X射线衍射（XRD）分析了分别加入合金化元素Ce，Si和Ca后AZ91D合金的铸态组织和相组成，测试了合金室温拉伸性能和硬度。结果表明：加入Ce和Si后合金组织中分别生成杆状Al4Ce和汉字状Mg2Si相，而加入Ca后无新相生成，加入的Ca主要固溶于β相中；Al4Ce和Mg2Si相在合金凝固过程中被推移到生长界面，Ca原子偏聚在生长界面前沿，从而阻碍枝晶的自由生长，细化合金铸态组织：Ce和Ca的加入可提高合金室温综合力学性能，且前者提高程度要高于后者提高程度，而Si的加入却降低合金室温综合力学性能。
利用光学显微镜（OM）和X射线衍射（XRD）分析了分别加入合金化元素Ce，Si和Ca后AZ91D合金的铸态组织和相组成，测试了合金室温拉伸性能和硬度。结果表明：加入Ce和Si后合金组织中分别生成杆状Al4Ce和汉字状Mg2Si相，而加入Ca后无新相生成，加入的Ca主要固溶于β相中；Al4Ce和Mg2Si相在合金凝固过程中被推移到生长界面，Ca原子偏聚在生长界面前沿，从而阻碍枝晶的自由生长，细化合金铸态组织：Ce和Ca的加入可提高合金室温综合力学性能，且前者提高程度要高于后者提高程度，而Si的加入却降低合金室温综合力学性能。
2006, 35(3):367-370.
Abstract:
研究了Ni33Al28Cr5.5Mo0.5Hf合金在900℃10T强磁场处理后的微观组织及室温力学性能，发现合金经强磁场处理后室温抗弯强度提高约75％，抗拉强度提高1倍多。强磁场处理使合金中Hf元素在NiAl/Cr（mo）相界处析出的块状Heusler相部分溶解，弥散分布在Cr（Mo）相界处的小颗粒几乎全部固溶至NiAl相基体。Heusler相在晶界处析出可能是导致合金室温强度低、韧性差的主要原因，强磁场处理改善了这一情形，使合金固溶强化加强，提高其力学性能。
研究了Ni33Al28Cr5.5Mo0.5Hf合金在900℃10T强磁场处理后的微观组织及室温力学性能，发现合金经强磁场处理后室温抗弯强度提高约75％，抗拉强度提高1倍多。强磁场处理使合金中Hf元素在NiAl/Cr（mo）相界处析出的块状Heusler相部分溶解，弥散分布在Cr（Mo）相界处的小颗粒几乎全部固溶至NiAl相基体。Heusler相在晶界处析出可能是导致合金室温强度低、韧性差的主要原因，强磁场处理改善了这一情形，使合金固溶强化加强，提高其力学性能。
2006, 35(3):371-374.
Abstract:
利用热机械模拟系统，对铸态Ti-50．3at％Ni合金进行高温形变循环热处理，研究不同热处理工艺对其组织细化的影响。结果表明：经过高温形变循环热处理，可以获得晶粒尺度在10μm以下的均匀单相显微组织。试样分别在55012和60012进行塑性变形，然后继续加热到80012短时保温进行不同的循环热处理，发现在55012变形后晶粒细化效果更加明显。还探讨了铸态Ti-50．3at％Ni合金高温形变循环热处理中组织的细化机理及其影响因素。
利用热机械模拟系统，对铸态Ti-50．3at％Ni合金进行高温形变循环热处理，研究不同热处理工艺对其组织细化的影响。结果表明：经过高温形变循环热处理，可以获得晶粒尺度在10μm以下的均匀单相显微组织。试样分别在55012和60012进行塑性变形，然后继续加热到80012短时保温进行不同的循环热处理，发现在55012变形后晶粒细化效果更加明显。还探讨了铸态Ti-50．3at％Ni合金高温形变循环热处理中组织的细化机理及其影响因素。
2006, 35(3):375-378.
Abstract:
研究了温度、等静压力对PbLa（Zr，Sn，Ti）O3陶瓷相变、介电常数（εr）及损耗（tanδ）的影响。结果表明：在温度场下，随着温度的升高，PbLa（Zr,Sn，Ti）O3陶瓷从四方反铁电相（AFET）转变为立方顺电相（PEc），在低温段出现频率弥散现象；在压力场下，随着等静压力的增加极化过的AFE陶瓷发生FE／AFE相变，同时伴随突然的释放电荷过程；在一定的等静压力下，经极化后变为铁电体的PbLa（Zr,Sn，Ti）O3陶瓷在温度的诱导下会转变为反铁电相，最后转变为顺电相；随着等静压力的增加，铁电／反铁电转变温度降低，反铁电／顺电转变温度上升。
研究了温度、等静压力对PbLa（Zr，Sn，Ti）O3陶瓷相变、介电常数（εr）及损耗（tanδ）的影响。结果表明：在温度场下，随着温度的升高，PbLa（Zr,Sn，Ti）O3陶瓷从四方反铁电相（AFET）转变为立方顺电相（PEc），在低温段出现频率弥散现象；在压力场下，随着等静压力的增加极化过的AFE陶瓷发生FE／AFE相变，同时伴随突然的释放电荷过程；在一定的等静压力下，经极化后变为铁电体的PbLa（Zr,Sn，Ti）O3陶瓷在温度的诱导下会转变为反铁电相，最后转变为顺电相；随着等静压力的增加，铁电／反铁电转变温度降低，反铁电／顺电转变温度上升。
2006, 35(3):379-382.
Abstract:
考察了几种不同掺锶量的理想化学配比锶磷灰石粉末在不同温度热处理后的相结构与化学成分,并观察其晶粒微观形貌与尺寸的变化。高温下HAP存在着分解和合并长大之间的竞争。随加热温度升高至1300℃,纯HAP基本不分解,但晶粒明显由600℃下20nm~40nm长大到1300℃下的~20μm;而Sr2+取代Ca2+固溶入磷灰石晶格后,因Sr2+半径较大且对磷灰石晶体生长有抑制作用,使掺锶磷灰石分解过程比合并长大过程更为有利,因此,掺锶磷灰石晶体900℃便开始部分分解生成磷酸三钙;随温度逐渐升高,掺锶磷灰石晶体分解加剧,同时晶体有所长大但幅度不如纯HAP明显,1300℃下仍维持类等轴形状(440nm~730nm×220nm~370nm);增大锶固溶量则加剧分解程度。
考察了几种不同掺锶量的理想化学配比锶磷灰石粉末在不同温度热处理后的相结构与化学成分,并观察其晶粒微观形貌与尺寸的变化。高温下HAP存在着分解和合并长大之间的竞争。随加热温度升高至1300℃,纯HAP基本不分解,但晶粒明显由600℃下20nm~40nm长大到1300℃下的~20μm;而Sr2+取代Ca2+固溶入磷灰石晶格后,因Sr2+半径较大且对磷灰石晶体生长有抑制作用,使掺锶磷灰石分解过程比合并长大过程更为有利,因此,掺锶磷灰石晶体900℃便开始部分分解生成磷酸三钙;随温度逐渐升高,掺锶磷灰石晶体分解加剧,同时晶体有所长大但幅度不如纯HAP明显,1300℃下仍维持类等轴形状(440nm~730nm×220nm~370nm);增大锶固溶量则加剧分解程度。
2006, 35(3):383-387.
Abstract:
By using MTS(Mechanical Threshold Stress)model and the experimental technique of the split Hopkinson bar with the synchronization assemblage,the dynamic constitutive equation of the unidirectional-solidified horizontal-continuous-casting polycrystal copper was investigated.In the narrow heated furnace designed and manufactured by NPU,the dynamic impact experiments at tempera-ture from 287 K to 1100 K were accomplished.The optimized parameters of the dynamic constitutive equation applying to the unidirectional-solidified horizontal-continuous-casting polycrystal copper were obtained and the theoretical stress-strain curves had a good agreement with experimental curves at temperature from 685 K to 1085 K.The concept of restoration threshold energy was proposed and the parameters of MTS model were also discussed in detail.The results show that only seven parameters in parameters of MTS model are independent and MTS model is not very good to describe the discreteness of mechanical properties,restoration,recrystallization and associated strain softening at temperature from 287 K to 685 K.
By using MTS(Mechanical Threshold Stress)model and the experimental technique of the split Hopkinson bar with the synchronization assemblage,the dynamic constitutive equation of the unidirectional-solidified horizontal-continuous-casting polycrystal copper was investigated.In the narrow heated furnace designed and manufactured by NPU,the dynamic impact experiments at tempera-ture from 287 K to 1100 K were accomplished.The optimized parameters of the dynamic constitutive equation applying to the unidirectional-solidified horizontal-continuous-casting polycrystal copper were obtained and the theoretical stress-strain curves had a good agreement with experimental curves at temperature from 685 K to 1085 K.The concept of restoration threshold energy was proposed and the parameters of MTS model were also discussed in detail.The results show that only seven parameters in parameters of MTS model are independent and MTS model is not very good to describe the discreteness of mechanical properties,restoration,recrystallization and associated strain softening at temperature from 287 K to 685 K.
2006, 35(3):388-390.
Abstract:
采用Sol-gel法合成了系列纳米材料La0.68Pb0.32Fe1-xMnxO3（x=0．0，0．1，0．2，0．4，0．6），研究了Mn掺杂对材料的导电特性和气敏特性的影响。研究表明：合成的系列纳米材料均具有正交钙钛矿结构，Mn的掺杂对材料La0.68Pb0.32FeO3的结构没有影响，且对材料粒径的影响较小；随Mn元素含量的增加，La0.68Pb0.32Fe-xMnxO3纳米粉体对丙酮的气敏性均迅速降低；Mn掺杂同时导致电阻率减小，这是由于形成Mn^3＋-O^2--Mn^4＋双交换作用键的缘故。
采用Sol-gel法合成了系列纳米材料La0.68Pb0.32Fe1-xMnxO3（x=0．0，0．1，0．2，0．4，0．6），研究了Mn掺杂对材料的导电特性和气敏特性的影响。研究表明：合成的系列纳米材料均具有正交钙钛矿结构，Mn的掺杂对材料La0.68Pb0.32FeO3的结构没有影响，且对材料粒径的影响较小；随Mn元素含量的增加，La0.68Pb0.32Fe-xMnxO3纳米粉体对丙酮的气敏性均迅速降低；Mn掺杂同时导致电阻率减小，这是由于形成Mn^3＋-O^2--Mn^4＋双交换作用键的缘故。
2006, 35(3):391-394.
Abstract:
A wear resistant Cr-Cu-Si metal silicide alloy having a microstructure consisting of the primary dual-phase dendrite with a Cr5Si3 core encapsulated by CrSi phase and the interdendritic ductile Cu-based solid solution was fabricated by the laser melting process. Microstructure of the Cr-Cu-Si metal silicide alloy was characterized by OM, SEM, XRD and EDS. Microhardness was measured using a MH-6 semi-automatic Vickers micro-hardness tester. Because the wear-resistant metal silicide CrsSi3 and CrSi have high hardness, strong covalent-dominated atomic bonds, and the ductile Cu-based solid solution has excellent thermal conductivity, low coefficient of friction and excellent ductility, the Cr-Cu-Si metal silicide alloy has excellent wear resistance under room temperature dry sliding wear test conditions.
A wear resistant Cr-Cu-Si metal silicide alloy having a microstructure consisting of the primary dual-phase dendrite with a Cr5Si3 core encapsulated by CrSi phase and the interdendritic ductile Cu-based solid solution was fabricated by the laser melting process. Microstructure of the Cr-Cu-Si metal silicide alloy was characterized by OM, SEM, XRD and EDS. Microhardness was measured using a MH-6 semi-automatic Vickers micro-hardness tester. Because the wear-resistant metal silicide CrsSi3 and CrSi have high hardness, strong covalent-dominated atomic bonds, and the ductile Cu-based solid solution has excellent thermal conductivity, low coefficient of friction and excellent ductility, the Cr-Cu-Si metal silicide alloy has excellent wear resistance under room temperature dry sliding wear test conditions.
2006, 35(3):395-398.
Abstract:
系统研究了Ti100-x-yVxFey（x=54，49，44；y=5，7．5，10）储氢合金的相结构及其吸放氢性能。XRD及SEM分析表明，Ti41V54Fes合金由体心立方（BCC）结构的固溶体主相和少量的α-Ti第二相组成；而Ti43．5V49Fe7．5和Ti46V44Fe10合金均为单一的BCC固溶体相。储氢性能测试表明，3种合金的动力学性能均很好，在室温和4MPa初始氢压条件下，无需氢化孕育期就能快速吸氢：经4次～5次吸放氢循环即能活化，仅2min～3min就能吸氢饱和达到最大吸氢量363．7ml／g-372．4ml／g；在300℃和0．1MPa放氢终压条件下，合金的放氢量在220．3ml／g-238．5ml／g之间。在所研究的合金中，Ti46V44Fe10合金的综合性能最佳，经4次吸放氢循环即活化，室温最大吸氢量可达372．4ml／g，放氢量达到238．5ml／g。
系统研究了Ti100-x-yVxFey（x=54，49，44；y=5，7．5，10）储氢合金的相结构及其吸放氢性能。XRD及SEM分析表明，Ti41V54Fes合金由体心立方（BCC）结构的固溶体主相和少量的α-Ti第二相组成；而Ti43．5V49Fe7．5和Ti46V44Fe10合金均为单一的BCC固溶体相。储氢性能测试表明，3种合金的动力学性能均很好，在室温和4MPa初始氢压条件下，无需氢化孕育期就能快速吸氢：经4次～5次吸放氢循环即能活化，仅2min～3min就能吸氢饱和达到最大吸氢量363．7ml／g-372．4ml／g；在300℃和0．1MPa放氢终压条件下，合金的放氢量在220．3ml／g-238．5ml／g之间。在所研究的合金中，Ti46V44Fe10合金的综合性能最佳，经4次吸放氢循环即活化，室温最大吸氢量可达372．4ml／g，放氢量达到238．5ml／g。
2006, 35(3):399-402.
Abstract:
采用提拉法生长出了掺钕钨酸铋钠（分子式Nd：NaBi（WO4）2，简称Nd：NBW）和掺钕钨酸钇钠（分子式Nd：NaY（WO4）2，简称Nd：NYW）晶体。通过TG-DTA分析得到Nd：NBW的熔点为936．2℃，Nd：NYW的熔点为1209．07℃。由吸收光谱可以看出，Nd：NBW在802nm有较强的吸收峰，Nd：NYW在804nm，752nm，586nm附近有较强、较宽的吸收峰，二者均适合于LD泵浦；并计算了晶体中Nd^＋3＋的吸收截面积。通过比较Nd：NBW和Nd：NYW的红外光谱和拉曼光谱结果，认为二者结构基本相同，为四方晶系、白钨矿结构、141/a空间群。
采用提拉法生长出了掺钕钨酸铋钠（分子式Nd：NaBi（WO4）2，简称Nd：NBW）和掺钕钨酸钇钠（分子式Nd：NaY（WO4）2，简称Nd：NYW）晶体。通过TG-DTA分析得到Nd：NBW的熔点为936．2℃，Nd：NYW的熔点为1209．07℃。由吸收光谱可以看出，Nd：NBW在802nm有较强的吸收峰，Nd：NYW在804nm，752nm，586nm附近有较强、较宽的吸收峰，二者均适合于LD泵浦；并计算了晶体中Nd^＋3＋的吸收截面积。通过比较Nd：NBW和Nd：NYW的红外光谱和拉曼光谱结果，认为二者结构基本相同，为四方晶系、白钨矿结构、141/a空间群。
2006, 35(3):403-407.
Abstract:
The microstructures of the rare-earth-based Low-Co AB5-type LaxMm1-x(NiMnSiAlFe)4.7Co0.2(x=0,1)alloys for hydrogen storage were determined by XRD and SEM,and the electrochemical performances of the as-cast and quenched alloys were measured synthetically.The effects of the substitution La for Mm on microstructures and electrochemical characteristics of the as-cast and quenched alloys were studied.The obtained results show that the substitution La for Mm extends the cycle life of the as-cast alloy and improves the discharge capacity of the alloys because the substitution La for Mm makes the secondary phase disappear and the cell volume enlarge.Rapid quenching can improve the cycle stability of the alloys,but it isn't notable to the as-quenched La1 alloy.It is mainly attributed to the larger grain produced by substitution La for Mm.
The microstructures of the rare-earth-based Low-Co AB5-type LaxMm1-x(NiMnSiAlFe)4.7Co0.2(x=0,1)alloys for hydrogen storage were determined by XRD and SEM,and the electrochemical performances of the as-cast and quenched alloys were measured synthetically.The effects of the substitution La for Mm on microstructures and electrochemical characteristics of the as-cast and quenched alloys were studied.The obtained results show that the substitution La for Mm extends the cycle life of the as-cast alloy and improves the discharge capacity of the alloys because the substitution La for Mm makes the secondary phase disappear and the cell volume enlarge.Rapid quenching can improve the cycle stability of the alloys,but it isn't notable to the as-quenched La1 alloy.It is mainly attributed to the larger grain produced by substitution La for Mm.
2006, 35(3):408-411.
Abstract:
Mo/Si thin films have been successful deposited on several substrates by using RF magnetron sputtering method and influence of these substrates on the phase structures,surface morphologies and electrical properties of the Mo/Si films have also been investigated.Results obtained from the analyses of X-ray diffraction(XRD),atomic force microscope(AFM)and scanning electrical microscopy(SEM)show that the films deposited on Si and quartz glass substrate are amorphous,but those deposited on Al2O3 substrate are polycrystalline.Four-probe resistance meter was used to characterize their sheet resistance and the results reveal that annealing temperature affects their sheet resistance significantly.As the increase of annealing temperature,the sheet resistance of the films deposited on Si and Al2O3 substrate decreases while the one of the films deposited on quartz glass substrate increases abnormally.
Mo/Si thin films have been successful deposited on several substrates by using RF magnetron sputtering method and influence of these substrates on the phase structures,surface morphologies and electrical properties of the Mo/Si films have also been investigated.Results obtained from the analyses of X-ray diffraction(XRD),atomic force microscope(AFM)and scanning electrical microscopy(SEM)show that the films deposited on Si and quartz glass substrate are amorphous,but those deposited on Al2O3 substrate are polycrystalline.Four-probe resistance meter was used to characterize their sheet resistance and the results reveal that annealing temperature affects their sheet resistance significantly.As the increase of annealing temperature,the sheet resistance of the films deposited on Si and Al2O3 substrate decreases while the one of the films deposited on quartz glass substrate increases abnormally.
2006, 35(3):412-417.
Abstract:
A least square method for separating two broadening effects caused by crystallite and micro-stress has been proposed and was applied to study the micro-structure of hydrogen storage alloys prepared by different methods. Changes of microstructure after activation and lifetime testing in Ni-MH battery have been comparatively investigated. The results show that the effect of activation on microstructure of the negative electrode material is significant. It is also found that the microstructure changes of the material are dependent on the lifetime testing conditions.
A least square method for separating two broadening effects caused by crystallite and micro-stress has been proposed and was applied to study the micro-structure of hydrogen storage alloys prepared by different methods. Changes of microstructure after activation and lifetime testing in Ni-MH battery have been comparatively investigated. The results show that the effect of activation on microstructure of the negative electrode material is significant. It is also found that the microstructure changes of the material are dependent on the lifetime testing conditions.
2006, 35(3):423-427.
Abstract:
Si3N4 Ceramics were bonded by brazing with bonding materials composed of Ag-Cu-Ti foils and Ti/Ni/Ti multi-interlayer,which enhance the joint strength by in situ reaction occurred while brazing.Ni-Ti-Cu intermetallic compounds were observed in the joints by X-ray analysis.The intermetallic particles are homogeneously distributed in the matrix so they contribute to the joint strength.The distribution of intermetallic compounds and the status of interfacial reaction layer have obvious effect on the joint strength.The interfacial reaction layer has a two-layer structure,and the formation of which has three steps.
Si3N4 Ceramics were bonded by brazing with bonding materials composed of Ag-Cu-Ti foils and Ti/Ni/Ti multi-interlayer,which enhance the joint strength by in situ reaction occurred while brazing.Ni-Ti-Cu intermetallic compounds were observed in the joints by X-ray analysis.The intermetallic particles are homogeneously distributed in the matrix so they contribute to the joint strength.The distribution of intermetallic compounds and the status of interfacial reaction layer have obvious effect on the joint strength.The interfacial reaction layer has a two-layer structure,and the formation of which has three steps.
21 A X-Ray Absorption Spectroscopy and X-Ray Excited Optical Luminescence Study of Silicon Nanowires
2006, 35(3):428-432.
Abstract:
X-ray absorption fine structures(XAFS)and X-ray excited optical luminescence(XEOL)at the Si K and Si L3,2 edge have been used to investigate the optoelectronic properties of Silicon nanowires.Although no noticeable blueshift of edge jump was observed in XAFS,a less steep rise and the blurring of spectral features was observed,indicating considerable degradation in the long-range order and small size effects.XAFS probes the average of a distribution of wires of various sizes of which the majority is too large to exhibit detectable quantum confinement behavior.The results of XEOL indicates that the luminescence of Si nanowires originate from the encapsulating silicon oxide,the quantum-confined silicon crystallites embedded in the oxide layer,and the interface states between silicon and silicon oxide.
X-ray absorption fine structures(XAFS)and X-ray excited optical luminescence(XEOL)at the Si K and Si L3,2 edge have been used to investigate the optoelectronic properties of Silicon nanowires.Although no noticeable blueshift of edge jump was observed in XAFS,a less steep rise and the blurring of spectral features was observed,indicating considerable degradation in the long-range order and small size effects.XAFS probes the average of a distribution of wires of various sizes of which the majority is too large to exhibit detectable quantum confinement behavior.The results of XEOL indicates that the luminescence of Si nanowires originate from the encapsulating silicon oxide,the quantum-confined silicon crystallites embedded in the oxide layer,and the interface states between silicon and silicon oxide.
2006, 35(3):433-436.
Abstract:
The influence of deformation temperature and strain rate on microstructure of Co4NiCrMo Alloy has been analyzed by isothermal compression test and metallurgical analysis.The results show that the grain size increases with the increase of deformation temperature and the grain size decreases with the increase from 0.001s^-1 to 1s^-1 of strain rate,but increases slightly with the increase from 1s^-1 to 10s^-1 of strain rate.The recrystallization volume fraction increases with the increases of strain and the grain size decreases with the increase of strain.
The influence of deformation temperature and strain rate on microstructure of Co4NiCrMo Alloy has been analyzed by isothermal compression test and metallurgical analysis.The results show that the grain size increases with the increase of deformation temperature and the grain size decreases with the increase from 0.001s^-1 to 1s^-1 of strain rate,but increases slightly with the increase from 1s^-1 to 10s^-1 of strain rate.The recrystallization volume fraction increases with the increases of strain and the grain size decreases with the increase of strain.
2006, 35(3):437-440.
Abstract:
Palladium/ferrum(Pd/Fe)film was deposited on the surface of 316L stainless steel by vacuum arc deposition technique followed by vacuum heat treatment.Effects of vacuum heat treatments on the morphology and phase constitution of Pd/Fe films were investigated.The results show that Even Pd/Fe film can be deposited on the surface of 316L stainless steel by vacuum arc deposition,and the diffuse heat treatment techniques have significant effects on the morphology and phase constitution of Pd/Fe film.Certain Pd-Fe alloy phase was formed through interdiffusion between Pd film and Fe film after treatment by 900 degrees centigrade for one hour.Along with the temperature increment of the diffuse heat treatment,the diffusion distance of Pd and Fe film into the 316L matrix increase,where as amount of chromium and nickel of the matrix diffused outwards to the films also increase.
Palladium/ferrum(Pd/Fe)film was deposited on the surface of 316L stainless steel by vacuum arc deposition technique followed by vacuum heat treatment.Effects of vacuum heat treatments on the morphology and phase constitution of Pd/Fe films were investigated.The results show that Even Pd/Fe film can be deposited on the surface of 316L stainless steel by vacuum arc deposition,and the diffuse heat treatment techniques have significant effects on the morphology and phase constitution of Pd/Fe film.Certain Pd-Fe alloy phase was formed through interdiffusion between Pd film and Fe film after treatment by 900 degrees centigrade for one hour.Along with the temperature increment of the diffuse heat treatment,the diffusion distance of Pd and Fe film into the 316L matrix increase,where as amount of chromium and nickel of the matrix diffused outwards to the films also increase.
2006, 35(3):441-446.
Abstract:
Sb掺杂SnO2(Antimonydopedtinoxide,简称ATO)纳米导电粉末具有优良的电学性能,少量的Sb掺杂即可达到抗静电要求,而且不改变基体的性质。采用非均相成核法制备了ATO纳米导电粉末,研究了晶种浓度、反应温度、分散剂对粉末粒径、电阻率等性能的影响;并对其进行了晶粒粒径、物相、微观结构、DTA-TG、表观形貌和能谱分析。结果表明,粉末晶粒粒径为6nm;掺杂Sb没有在SnO2中形成新相;电阻率为0.23?·cm;ATO干凝胶的煅烧过程经历了4个过程;ATO颗粒呈不规则的椭圆状,且分散良好;Sb掺杂均匀性一般。
Sb掺杂SnO2(Antimonydopedtinoxide,简称ATO)纳米导电粉末具有优良的电学性能,少量的Sb掺杂即可达到抗静电要求,而且不改变基体的性质。采用非均相成核法制备了ATO纳米导电粉末,研究了晶种浓度、反应温度、分散剂对粉末粒径、电阻率等性能的影响;并对其进行了晶粒粒径、物相、微观结构、DTA-TG、表观形貌和能谱分析。结果表明,粉末晶粒粒径为6nm;掺杂Sb没有在SnO2中形成新相;电阻率为0.23?·cm;ATO干凝胶的煅烧过程经历了4个过程;ATO颗粒呈不规则的椭圆状,且分散良好;Sb掺杂均匀性一般。
2006, 35(3):447-450.
Abstract:
Effects of preparation technology on structure and thermoelectric properties of NixCo4-xSb12(x=0.1~0.5)were investigated separately by solid reaction-spark plasma sintering(SR-SPS)and mechanical milling-spark plasma sintering(MG-SPS)method.The two methods had little effect on phase structure and Seebeck coefficient,but SR-SPS technology augments electrical resistivity and the grain size of products when the content of Ni was as low as 0.1,and hence increase the thermal conductivity and decrease the thermoelectric properties.Compared with SR-SPS,MG-SPS method not only is simple and convenient in preparation,but also is propitious to the improvement the thermoelectric properties.In our experimental range,the Ni0.2Co3.8Sb12 bulk sintered by MG-SPS shows maximum ZT value of 0.6 at about 773 K.
Effects of preparation technology on structure and thermoelectric properties of NixCo4-xSb12(x=0.1~0.5)were investigated separately by solid reaction-spark plasma sintering(SR-SPS)and mechanical milling-spark plasma sintering(MG-SPS)method.The two methods had little effect on phase structure and Seebeck coefficient,but SR-SPS technology augments electrical resistivity and the grain size of products when the content of Ni was as low as 0.1,and hence increase the thermal conductivity and decrease the thermoelectric properties.Compared with SR-SPS,MG-SPS method not only is simple and convenient in preparation,but also is propitious to the improvement the thermoelectric properties.In our experimental range,the Ni0.2Co3.8Sb12 bulk sintered by MG-SPS shows maximum ZT value of 0.6 at about 773 K.
2006, 35(3):451-454.
Abstract:
采用化学共沉淀法,以InCl3?5H2O和SnCl4?5H2O为原料,在掺杂浓度In2O3与SnO2的质量比为9:1的条件下,合成了平均粒径80nm的ITO粉体。利用TEM,XRD,DSC-TG,IR,ζ电位分析仪等实验方法对粉体的形貌、物相、结构等进行了表征。实验结果表明,当前驱体煅烧温度为600℃时,可以获得晶化良好的立方In2O3结构的In2O3和SnO2固溶体。根据ζ电位测定和TEM的观察结果,当反应的最终pH值为9时,粉体的分散性较好。
采用化学共沉淀法,以InCl3?5H2O和SnCl4?5H2O为原料,在掺杂浓度In2O3与SnO2的质量比为9:1的条件下,合成了平均粒径80nm的ITO粉体。利用TEM,XRD,DSC-TG,IR,ζ电位分析仪等实验方法对粉体的形貌、物相、结构等进行了表征。实验结果表明,当前驱体煅烧温度为600℃时,可以获得晶化良好的立方In2O3结构的In2O3和SnO2固溶体。根据ζ电位测定和TEM的观察结果,当反应的最终pH值为9时,粉体的分散性较好。
2006, 35(3):455-458.
Abstract:
Microstructure, streamline and Microhardness of different size BTI6 locknuts have been analyzed and compared with 08 mm thread made of BT16. The results show that the microstructure of BT16 fastener is lamellar type with very fine grain size, which may be obtained by deformed starting in beta field. Microstructure of fastener is very similar with that of thread in annealing state, which show that the fastener is used in annealing state without solution and aging treatment. Streamline and hardness analyses show that fastener is deformed in cold condition.
Microstructure, streamline and Microhardness of different size BTI6 locknuts have been analyzed and compared with 08 mm thread made of BT16. The results show that the microstructure of BT16 fastener is lamellar type with very fine grain size, which may be obtained by deformed starting in beta field. Microstructure of fastener is very similar with that of thread in annealing state, which show that the fastener is used in annealing state without solution and aging treatment. Streamline and hardness analyses show that fastener is deformed in cold condition.
2006, 35(3):459-462.
Abstract:
The hydroxyapatite coatings on an anodized titanium substrate were prepared by electrodeposition technique.Properties of coatings were investigated by scanning electron microscopy(SEM),X-ray diffraction(XRD)respectively.The results show that hydroxyapatite crystal is porous-like flakes at the beginning time of the deposition.The thickness of the coatings increase and its morphology changes from porous-like flakes to petal-like flakes with the increase of voltage,time and concentration of electrolyte.The bonding strength of coatings with the substrate is improved by anodic oxidation.
The hydroxyapatite coatings on an anodized titanium substrate were prepared by electrodeposition technique.Properties of coatings were investigated by scanning electron microscopy(SEM),X-ray diffraction(XRD)respectively.The results show that hydroxyapatite crystal is porous-like flakes at the beginning time of the deposition.The thickness of the coatings increase and its morphology changes from porous-like flakes to petal-like flakes with the increase of voltage,time and concentration of electrolyte.The bonding strength of coatings with the substrate is improved by anodic oxidation.
2006, 35(3):463-466.
Abstract:
Ga2O3 films were deposited onto Si(111)substrates with radio frequency(r.f.)magnetron sputtering system.They self-assembled into GaN films after reacted with ammonia.The lattice mismatch between substrates and epitaxy layer affects the films' quality.In order to optimize the films,thin SiC films as intermediate layers also deposited onto the substrate with magnetron sputtering.The samples intermediate were compared.The results indicate intermediate layer's positive effect to GaN films.
Ga2O3 films were deposited onto Si(111)substrates with radio frequency(r.f.)magnetron sputtering system.They self-assembled into GaN films after reacted with ammonia.The lattice mismatch between substrates and epitaxy layer affects the films' quality.In order to optimize the films,thin SiC films as intermediate layers also deposited onto the substrate with magnetron sputtering.The samples intermediate were compared.The results indicate intermediate layer's positive effect to GaN films.
2006, 35(3):467-471.
Abstract:
The La-Mg-Ni system(PnNi3-type)electrode alloys La2Mg(Ni0.85Co0.15)9Bx(x = 0,0.1,0.2)were prepared by casting and rapid quenching.The microstructures and electrochemical performances of the as-cast and quenched alloys were determined and measured.The effects of boron content and quenching rate on the microstructures and electrochemical properties of the alloys were investigated in detail.The results show that the as-cast and quenched alloys are composed of the(La,Mg)Ni3 phase(PuNi3-type structure),the LaNi5 phase and the LaNi2 phase.A trace of the Ni2B phase exists in the as-cast alloys containing boron,and after the as-cast alloys are quenched,the Ni2B phase in the alloys nearly disappears.The relative amount of each phase in the alloys depends on the composition of the alloys and the quenching rate.The capacity of the alloys without boron monotonously decreases with the increase of the quenching rate,but for the alloys containing boron,the capacities have a maximum value with the variety of the quenching rate.The cycle lives of the as-quenched alloys increase with the increase of the quenching rate.The activation performances of the as-cast and quenched alloys are excellent.
The La-Mg-Ni system(PnNi3-type)electrode alloys La2Mg(Ni0.85Co0.15)9Bx(x = 0,0.1,0.2)were prepared by casting and rapid quenching.The microstructures and electrochemical performances of the as-cast and quenched alloys were determined and measured.The effects of boron content and quenching rate on the microstructures and electrochemical properties of the alloys were investigated in detail.The results show that the as-cast and quenched alloys are composed of the(La,Mg)Ni3 phase(PuNi3-type structure),the LaNi5 phase and the LaNi2 phase.A trace of the Ni2B phase exists in the as-cast alloys containing boron,and after the as-cast alloys are quenched,the Ni2B phase in the alloys nearly disappears.The relative amount of each phase in the alloys depends on the composition of the alloys and the quenching rate.The capacity of the alloys without boron monotonously decreases with the increase of the quenching rate,but for the alloys containing boron,the capacities have a maximum value with the variety of the quenching rate.The cycle lives of the as-quenched alloys increase with the increase of the quenching rate.The activation performances of the as-cast and quenched alloys are excellent.
2006, 35(3):472-475.
Abstract:
The nano-sized MoO3/PMMA hybrid material was prepared by in-situ polymerization method. XRD patterns show that the hybrid material is amorphous. SEM indicates that the morphology of fracture plane of the hybrid material is different when MoO3 content is varied in the hybrid materials, and the fragility increase with the increase of MoO3 content. EDS reveals that the content of Mo is 1.09%. It is found that the transmissivity, solubility, hardness and fracture strength of the hybrid materials decrease with the increase of MoO3 content.
The nano-sized MoO3/PMMA hybrid material was prepared by in-situ polymerization method. XRD patterns show that the hybrid material is amorphous. SEM indicates that the morphology of fracture plane of the hybrid material is different when MoO3 content is varied in the hybrid materials, and the fragility increase with the increase of MoO3 content. EDS reveals that the content of Mo is 1.09%. It is found that the transmissivity, solubility, hardness and fracture strength of the hybrid materials decrease with the increase of MoO3 content.
2006, 35(3):476-479.
Abstract:
利用原位自生法合成的纳米晶粒细化剂,成功的克服了颗粒团聚,有效的抑制了颗粒的沉降。本试验用其对ZL101合金的细化行为进行了研究。试验结果表明:加入量为0.2%(质量分数)时,纳米晶粒细化剂可有效地细化初晶α-Al,改善共晶硅的形貌及尺寸,细化后铸态α-Al枝晶尺寸由44μm减小至23μm;经T6处理的细化后试样其拉伸断口为韧窝断口,且韧窝明显多于未细化试样;加入细化剂后保温30min,与未细化合金相比,抗拉强度提高了28MPa,屈服强度提高了22MPa,延伸率增加了2.6%;同时细化后合金的阻尼性能较未细化合金有了大幅提高,0.5Hz时细化后室温阻尼性能Q-1=13×10-3,较之细化前Q-1提高了5×10-3。
利用原位自生法合成的纳米晶粒细化剂,成功的克服了颗粒团聚,有效的抑制了颗粒的沉降。本试验用其对ZL101合金的细化行为进行了研究。试验结果表明:加入量为0.2%(质量分数)时,纳米晶粒细化剂可有效地细化初晶α-Al,改善共晶硅的形貌及尺寸,细化后铸态α-Al枝晶尺寸由44μm减小至23μm;经T6处理的细化后试样其拉伸断口为韧窝断口,且韧窝明显多于未细化试样;加入细化剂后保温30min,与未细化合金相比,抗拉强度提高了28MPa,屈服强度提高了22MPa,延伸率增加了2.6%;同时细化后合金的阻尼性能较未细化合金有了大幅提高,0.5Hz时细化后室温阻尼性能Q-1=13×10-3,较之细化前Q-1提高了5×10-3。
2006, 35(3):480-483.
Abstract:
采用脉冲和直流电沉积方式，以FeSO4，（NH4）2SO4等混合溶液为电解液，在多孔阳极氧化铝模板（AAO模板）微孔内成功制备出Fe磁性纳米线阵列。用X射线衍射仪、扫描电镜及HP8510B网络分析仪对多孔AAO模板以及Fe磁性纳米线阵列的微观形貌、组织结构及微波吸收性能进行了测试。结果表明，沉积的纳米线为立方结构α=Fe，且纳米线阵列存在（110）择优取向性。Fe纳米线组装后的铝基AAO模板吸波材料具有良好的微波吸收效果，在2GHz～18GHz频段内的最大反射率为-4．8dB，大于-1dB的吸收带宽约为10GHz。
采用脉冲和直流电沉积方式，以FeSO4，（NH4）2SO4等混合溶液为电解液，在多孔阳极氧化铝模板（AAO模板）微孔内成功制备出Fe磁性纳米线阵列。用X射线衍射仪、扫描电镜及HP8510B网络分析仪对多孔AAO模板以及Fe磁性纳米线阵列的微观形貌、组织结构及微波吸收性能进行了测试。结果表明，沉积的纳米线为立方结构α=Fe，且纳米线阵列存在（110）择优取向性。Fe纳米线组装后的铝基AAO模板吸波材料具有良好的微波吸收效果，在2GHz～18GHz频段内的最大反射率为-4．8dB，大于-1dB的吸收带宽约为10GHz。
2006, 35(3):484-487.
Abstract:
Taking Nb and Si elemental powders as raw materials,dense Nb/Nb5Si3 composites were successfully fabricated by a spark plasma sintering(SPS)technology.The microstructural features of the synthesized composites were analyzed by OM,SEM,XRD and EPMA.The formation mechanism of the composites was also investigated by a quenching test.The results show that the prepared composites consist of Nb and Nb5Si3 phases,and Nb particles uniformly distribute in the in-situ synthesized Nb5Si3 matrix.During the SPS process,an interfacial reaction occurs between Nb and Si particles to synthesize Nb5Si3 until reactant silicon has been completely reacted.
Taking Nb and Si elemental powders as raw materials,dense Nb/Nb5Si3 composites were successfully fabricated by a spark plasma sintering(SPS)technology.The microstructural features of the synthesized composites were analyzed by OM,SEM,XRD and EPMA.The formation mechanism of the composites was also investigated by a quenching test.The results show that the prepared composites consist of Nb and Nb5Si3 phases,and Nb particles uniformly distribute in the in-situ synthesized Nb5Si3 matrix.During the SPS process,an interfacial reaction occurs between Nb and Si particles to synthesize Nb5Si3 until reactant silicon has been completely reacted.
2006, 35(3):488-491.
Abstract:
采用金属有机物化学气相沉积法，在不通入活性气体的条件下，研究了三乙酰丙酮铱先驱体挥发温度对铱涂层显微结构的影响。在500℃的金属铌和陶瓷石英基片上制备出亮银白色的多晶相铱涂层。分析表明：铌和石英基片上沉积的铱涂层均由两层不同结构的薄膜构成，220℃挥发先驱体沉积出由纳米级颗粒疏松堆积构成的涂层，185℃挥发先驱体沉积出致密的涂层。铱涂层表面光滑均匀，无明显缺陷。
采用金属有机物化学气相沉积法，在不通入活性气体的条件下，研究了三乙酰丙酮铱先驱体挥发温度对铱涂层显微结构的影响。在500℃的金属铌和陶瓷石英基片上制备出亮银白色的多晶相铱涂层。分析表明：铌和石英基片上沉积的铱涂层均由两层不同结构的薄膜构成，220℃挥发先驱体沉积出由纳米级颗粒疏松堆积构成的涂层，185℃挥发先驱体沉积出致密的涂层。铱涂层表面光滑均匀，无明显缺陷。
2006, 35(3):496-499.
Abstract:
Anisotropic bonded NdFe12Nx magnets have been prepared by different technical route and the factors which have effects on the orientation degree of the anisotropic bonded magnets have also been analyzed. The results show that a good alignment can be achieved with the combination of solvent processing and being pulse-magnetized in preparing anisotropic bonded NdFe12Nx magnets. As a result anisotropic bonded NdFe12Nx magnets with excellent magnetic properties can be made.
Anisotropic bonded NdFe12Nx magnets have been prepared by different technical route and the factors which have effects on the orientation degree of the anisotropic bonded magnets have also been analyzed. The results show that a good alignment can be achieved with the combination of solvent processing and being pulse-magnetized in preparing anisotropic bonded NdFe12Nx magnets. As a result anisotropic bonded NdFe12Nx magnets with excellent magnetic properties can be made.
2006, 35(3):500-504.
Abstract:
The formation principal and its physical meanings of the EBSP(Electron Back-Scattered Diffraction Pattern)have been introduced in the present paper.Some application examples on the determination of crystal orientation,micro-texture,crystallographic orientation relationship,stress distribution,lattice parameters,phase identification and boundary nature study with EBSD have been given.
The formation principal and its physical meanings of the EBSP(Electron Back-Scattered Diffraction Pattern)have been introduced in the present paper.Some application examples on the determination of crystal orientation,micro-texture,crystallographic orientation relationship,stress distribution,lattice parameters,phase identification and boundary nature study with EBSD have been given.
