共查询到19条相似文献,搜索用时 896 毫秒
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采用熔体单辊旋淬法制备了快凝Al87Ni7Cu3Nd3合金条带,利用差热扫描热力学(DSC)分析、X射线衍射(XRD)分析等手段对比研究了快凝合金条带及其不同退火态材料的晶化行为.选择合适工艺条件,对快凝合金条带进行等温加热退火,采用高分辨透射电镜(HRTEM)观察分析了等温退火态材料显微组织特征.结果表明,快凝Al87Ni7Cu3Nd3合金薄带呈现出完全均匀的非晶态结构.随加热温度升高,非晶态薄带的晶化过程包括两个主要的相转变: α-Al晶体从非晶基体中析出的初始晶化以及有Al3Ni,Al11Nd3和Al8Cu3Nd形成的第二次晶化过程.在低于310 ℃下加热,快速凝固Al87Ni7Cu3Nd3金属玻璃中发生的主要相转变是富Al非晶的初始晶化.110 ℃等温退火态薄带主要是由α-Al加残余非晶相的两相组成,α-Al晶体纳米颗粒均匀弥散分布在残余非晶基体上.而在310 ℃热暴露后的退火试样中,在除α-Al晶体外的残留非晶相中开始出现极少量的Al3Ni金属间化合物. 相似文献
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提出了以自制的标准样品,采用单点法绘制校准曲线,利用X射线荧光光谱仪测定FeSiB非晶薄带样品中硅、硼和铁的含量。对于4个FeSiB非晶合金薄带样品中硅、硼和铁进行了10次测定,其分析结果的相对标准偏差分别为0.4~0.5%,1.3~4.2%和0.2~0.4%。本方法的分析结果与火花源原子发射光谱法、化学重量法和ICP-AES的测定值吻合较好。本方法快速、简便,薄带样品无需制样,适用于FeSiB非晶合金薄带的快速成分分析。 相似文献
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在高真空电弧熔炼及单辊旋淬一体炉制备钐铁合金薄带实验中,通过控制辊轮转速来实现不同的冷却速率(10~5~10~6K·s~(-1))。在快速冷凝钐铁合金的过程中,由于存在非常高的温度梯度,落至辊轮上的合金液滴会迅速冷凝成连续的非晶或微晶薄带。通过XRD物相检测手段研究快淬钐铁合金不同速率下的相结构演变。结果表明:在常规冷却条件下凝固得到的钐铁合金中具有α-Fe,SmFe_3,SmFe_2和Sm_2Fe_(17)4种物相;在快速冷凝条件下,钐铁合金的α-Fe相消失,随着冷却速率增大,SmFe_3相也消失,合金中只剩下SmFe_2和Sm_2Fe_(17)相;冷却速率继续增大时,快淬钐铁中出现非晶,且随着冷却速率的增大,非晶含量增多;此外,当快淬速率升至36.5 m·s~(-1)时,非晶含量可达到50%左右。 相似文献
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提出了以自制的标准样品,采用单点法绘制校准曲线,利用X射线荧光光谱仪测定FeSiB非晶薄带样品中硅、硼和铁的含量。对于4个FeSiB非晶合金薄带样品中硅、硼和铁进行了10次测定,其分析结果的相对标准偏差分别为0.4%~0.5%、1.3%~4.2%和0.2%~0.4%。方法的分析结果与火花源原子发射光谱法、化学重量法和电感耦合等离子体原子发射光谱(ICP-AES)法的测定值吻合较好。方法快速、简便,薄带样品无需制样,适用于FeSiB非晶合金薄带的快速成分分析。 相似文献
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纳米Ni-B非晶态合金的催化性质研究 总被引:2,自引:0,他引:2
纳米Ni-B非晶态合金的催化性质研究杨军,崔黎丽,邓景发(复旦大学化学系,第二军医大学药学院,上海,200433)关键词纳米材料,非晶态合金,催化性质纳米非晶材料融合了纳米晶与非晶材料的特性,既有很高的表面原子比,又呈高度几何无序状态。与普通非晶材料... 相似文献
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应用单辊甩带法制备非晶态Fe78Si13B9和Fe73.5Si13.5B9Nb3Cu1薄带,并以非晶晶化退火法制备出纳米晶Fe73.5Si13.5B9Nb3Cu1薄带.利用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.并用电化学极化曲线的方法和电化学阻抗技术研究了非晶态Fe78Si13B9和纳米晶Fe73.5Si13.5B9Nb3Cu1合金在1mol/LNaOH溶液里的电化学腐蚀行为,用SEM对极化测试后的试样形貌进行了观察;同时还研究了不同的热处理温度对材料结构及在1mol/LNaOH溶液里耐腐蚀性能的影响.结果表明,该非晶薄带的晶化过程分为两步;纳米晶比非晶合金的耐腐蚀性要好;且随着热处理温度的升高,非晶和纳米晶的耐腐蚀性能都得到提高. 相似文献
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研究了Ti和C添加对Nd9.4Fe79.6-xTixB11-yCy(x=0,1,2,4,6;y=0.5,1.5,3)合金晶化方式、显微结构和磁性能的影响规律。结果表明,适量Ti和C添加改变了合金的晶化方式,使-αFe相和Nd2Fe14B相同时从Nd9.4Fe75.6Ti4B10.5C0.5非晶基体中析出,避免了先析出相晶粒的长大,利于获得细小均匀的显微结构。适量Ti和C添加的Nd-Fe-B-Ti-C非晶合金在退火过程中易析出细小弥散的TiC和TiB2相,可作为形核质点促进形核,且可抑制晶粒长大,最终形成细小均匀的显微结构。综合性能较佳的Nd9.4Fe75.6Ti4B10.5C0.5合金退磁曲线具有优异的方形度,最佳退火条件下合金薄带的剩磁Br为0.91 T,矫顽力iHc为976 kA.m-1,磁能积(BH)max达135 kJ.m-3。文章最后对Ti和C添加合金微结构的形成机制进行了探讨。 相似文献
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A. Cserei E. Kuzmann A. Vértes L. Pöppl I. A. Novochatskii 《Journal of Radioanalytical and Nuclear Chemistry》1993,176(5):429-442
Mössbauer spectroscopy, X-ray diffractometry and differential scanning calorimetry were used to study the effect of the preparation parameters on the short range ordering of Fe83P17 amorphous alloys. The samples were quenched with different quenching rates from the melt which was kept either at 1100°C or 1250°C for 20 min. The short range order of the amorphous samples was found to depend on the quenching rate due to the relaxation taking place during rapid quenching of the melt. In one case, in the sample quenched with the lowest quenching rate from the melt of 1250°C, crystalline phases identified as Fe3P and -Fe were also found. This phase separation can be understood by taking into consideration the effect of both the melt temperature and the quenching rate. In this case, the cooling time can be long enough for separation of the phases which can be expected within the range of 1040–1250°C according to the phase diagram. 相似文献
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Non-isothermal short-range-order kinetics of binary alloys as influenced by solute-vacancy complexes
A model describing the roles of bound and unbound vacancies is proposed in order to predict defect decay and short-range-order
kinetics of quenched binary alloys during linear heating experiments. This is an alternative treatment of a previous approach.
The model has been applied to the differential scanning calorimetry (DSC) curves of Cu-5 at.% Zn quenched from different temperatures.
An expression to calculate the activation energy for migration of solute-vacancy complexes was also developed which make use
of DSC trace data. A value of 89.12±0.32 kJ mol-1 was obtained for the above alloy. The relative contribution of bound and unbound vacancies to partition of effective activation
energy corresponding to the ordering process as influenced by quenching temperature was also assessed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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纳米Co-B非晶态合金对高氯酸铵分解的催化性能 总被引:1,自引:0,他引:1
利用化学还原法制备了纳米 Co-B 非晶态合金,并用透射电镜、X射线衍射、差示扫描量热和N2吸附表面积测试等技术对样品进行了表征. 运用差热分析研究了纳米 Co-B 非晶态合金对高氯酸铵(AP)分解的催化性能. 结果表明,加入 Co-B 非晶态合金后AP的高低温放热峰相连,合并成一个高而大的放热峰,且峰温有很大程度的降低, 这说明纳米 Co-B 非晶态合金对AP热分解有很好的催化活性. 同时, Co-B 非晶态合金能使AP的表观分解热显著增大. 相似文献
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铸态和快淬态Mm(NiCoMnAl)5Bx (x=0~0.4)贮氢合金的微观结构与电化学性能 总被引:2,自引:0,他引:2
用铸造及快淬工艺制备了低钴AB5型MmNi3.8Co0.4Mn0.6Al0.2Bx (x=0, 0.1, 0.2, 0.3, 0.4)贮氢合金, 分析测试了铸态及快淬态合金的微观结构与电化学性能, 研究了硼及快淬工艺对合金微观结构及电化学性能的影响. 结果表明, 铸态合金具有双相组织, 主相为CaCu5型相, 还有少量CeCo4B第二相, 第二相的相丰度随硼含量x的增加而增大. 对合金进行了不同淬速的快淬处理, 随淬速的增加, 合金中第二相的量减少. 快淬使合金的晶格参数略有增大. 快淬工艺对合金的电化学性能产生显著影响, 随淬速的增加, 合金的容量下降, 循环稳定性显著提高. 快淬使合金的活化性能降低, 但随着硼含量的增加, 活化性能、高倍率放电能力及放电电压特性均得到不同程度的改善. 相似文献
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Ni-Mo-B非晶态合金纳米颗粒的抗氧化性能研究 总被引:6,自引:0,他引:6
在水溶液体系中用化学还原法制备Ni-B和Ni-Mo-B非晶态合金纳米颗粒.SEM测试表明,样品的颗粒形貌呈球形或类球形,平均粒径约10nm.XPS分析结果表明,Ni-Mo-B非晶态合金中钼元素主要以氧化态形成于合金的表面,并导致合金表面合金化硼原子浓度显著增加,氧化态硼(B3+)的原子浓度显著减少,氧的原子浓度明显减少,合金化镍的原子浓度显著增加,氧化态镍(Ni3+)的原子浓度显著减少.因此,Ni-Mo-B合金的抗氧化性能显著高于Ni-B合金.XPS谱图分析还表明,在Ni-B和Ni-Mo-B非晶态合金中,存在Ni和B的合金化物Ni2B,其中B失去部分电子,而Ni则富余电子.Ni2B的氧化产生副产物Ni2O3和B2O3. 相似文献
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IntroductionAmorphous.alloy has been found to have superior catalytic properties["']. However, asan applied catalyst, its small surface area and low thermal stability during the catalytic processare the encountered problems usually.In the previous study, we found that addition of a small amount of rare earth element effectively stabilized the amorphous phase in a Ni--P alloyL'~'j, and the surface area of the amorphous Ni--RE--P alloy could be greatly enlarged by introducing Al into the Ni-… 相似文献
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The system formed by isotactic polypropylene (iPP) and hydrogenated oligo(cyclopentadiene) (HOCP) is investigated in order to study the influence of the composition and thermal history on the morphology, phase structure, miscibility and thermal and mechanical properties of the blends. A phase diagram presenting both the lower and the upper cloud point curves is proposed. It is shown that these blends assume different morphologies and consequently present diverse thermal and dynamic-mechanical behaviours depending on quenching processes from one-phase region or two-phase region. From the analyses of the results of optical microscopy, WAXS, DSC and DMTA techniques it is found that: blend films, quenched from the melt of one-phase region to room temperature, contain one amorphous phase and iPP in smectic form; moreover they are transparent and possess a reduced permeability to oxygen and aroma; conversely when the samples are quenched from the melt of two-amorphous phase region there is the formation of two amorphous phases (the iPP-rich phase and the HOCP-rich phase) and at room temperature the iPP crystallizes in the monoclinic α form. 相似文献