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Mg2Ni纳米晶储氢材料的机械合金化制备工艺研究 总被引:8,自引:0,他引:8
利用机械合金化方法制备了Mg2Ni纳米晶粉末,根据不同球磨参数下样品的X射线衍射结果,分析了球磨过程中相组成、粉末晶粒度等的变化,研究了球磨时间、球磨转速、过程控制剂等工艺条件对粉末晶粒度、机械合金化程度的影响.结果表明:在较高的转速下进行循环变速运行并加入合适的过程控制剂可以使生成Mg2Ni的时间提前,完全合金化的过程缩短,得到的Mg2Ni晶粒度为10nm左右.对Mg2Ni纳米晶粉末进行了初步的贮氢性能研究,结果表明:机械合金化制备的样品在室温下即可吸氢,贮氢性能较之传统材料有较大改善. 相似文献
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为了改善Mg2Ni合金的贮氢性能,用Cu部分替代合金中的Ni,用快淬工艺制备了纳米晶Mg2Ni型Mg20Ni10-xCux(x=0、1、2、3、4)合金。用XRD、SEM、HRTEM分析了铸态及快淬态合金的微观结构;用自动控制的Sieverts设备测试了合金的吸放氢动力学性能;用程控电池测试仪测试了合金电极的电化学贮氢性能。结果表明,所有的快淬态合金具有纳米晶结构,Cu替代Ni及快淬处理没有改变合金的Mg2Ni型主相。合金的吸放氢容量及动力学随淬速的增加而增加。此外,快淬处理显著地提高了合金的电化学贮氢容量,但使循环稳定性下降。 相似文献
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Cu的添加对Mg2Ni合金储氢性能的影响 总被引:1,自引:0,他引:1
采用机械合金化法,制备了Mg2Ni1-xCux(x=0、0.1、0. 3)合金,研究了Cu对Mg2Ni储氢合金储氢性能的影响.XRD和SEM研究表明Cu的加入使合金中产生了Cu11Mg10Ni9新相.利用PCT测试仪测定了合金的储氢性能,结果表明,添加Cu元素会降低合金的吸氢量,但能有效地提高放电容量和循环稳定性.制备出的Mg2Ni0.9Cu0.1与Mg2Ni0.7Cu0.3相比,前者具有较大的吸氢量,后者的放电容量较大,循环稳定性较好. 相似文献
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以不经压制的Mg、Ni混合粉末为原料,利用氢化燃烧合成法在合成温度850 K和1.8 MPa初始合成氢压下制备了镁基储氢合金氢化物Mg2NiH4,并利用XRD及PCT仪分析了其物相组成和储氢性能.研究表明,产物由单一物相Mg2NiH4组成,无未反应的Ni和不完全氢化的Mg2NiH0.3;相对于传统熔炼法制备的Mg2Ni,氢化燃烧合成产物具有更高的氢化活性,在没有任何活化处理的前提下,第一次吸氢就能以很快的速度达到饱和吸氢量,同时在任何吸氢温度下均具有较好的吸氢动力学性能,且随温度的降低,最大吸氢量降低幅度较小,平台压和吸放氢温度的关系为:lgP(0.1 MPa)=-3 187.6/ T 6.362 4(吸氢),lgP(0.1 MPa)=-3 468.4/T 6.694 3(放氢). 相似文献
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为了改善Mg2Ni型合金的吸放氢动力学性能,用Co部分替代合金中的Ni。用快淬工艺制备了纳米晶和非晶Mg20Ni10-xCox(x=0,1,2,3,4)贮氢合金,分析了铸态及快淬态合金的微观结构,测试了合金的吸放氢动力学性能。研究了Co替代Ni及快淬工艺对合金吸放氢动力学性能的影响。结果表明,在快淬合金(x=0)中没有发现非晶相,但快淬合金(x=4)显示了纳米晶/非晶结构,表明Co替代Ni提高了Mg2Ni型合金的非晶形成能力。Co替代Ni不改变合金的Mg2Ni主相,但形成了第二相MgCo2。随Co替代量的增加,合金的吸氢量先增加而后减少,但其放氢量随Co替代量的增加而单调增加。 相似文献
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机械合金化(Mg+Mg2 Ni)+TiO2合金的储氢性能 总被引:1,自引:0,他引:1
用机械合金化法合成了(Mg Mg2Ni) TiO2储氢合金,借助XRD分析了TiO2的加入对合金的物相结构的影响,SEM考察了合金的形貌.TiO2在合金的吸放氢过程中起到很好的催化作用,降低合金放氢温度并且提高合金储氢量,(Mg Mg2Ni) 10wt%TiO2合金在573K下的储氢量是5.84wt%. 相似文献
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采用机械合金化制备了Mg76-xVxTi12Ni12(x=4、8、12、16)合金,通过X射线衍射(XRD)、扫描电子显微镜(SEM)和压强-成分-温度(PCT)等分析方法对合金粉末进行分析和表征。结果表明,合金相主要由Mg2Ni相和Ti2Ni相组成,Mg76-xVxTi12Ni12(x=4、8、12、16)合金贮氢量(质量分数,下同)分别为3.71%、3.12%、2.85%和2.33%,随着V含量的增加,合金的贮氢量下降,合金氢化物释氢率分别为95.1%、97.1%、84.9%和94.4%,适量的V能提高合金氢化物的释氢率。 相似文献
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Nanostructured Mg-Ni alloy with the particle size in the range of 40-50 nm was synthesized by the thermal decomposition of bipyridyl complexes of Mg and Ni metals at 773 K for 24 h under dry argon gas ambient. The as-prepared nano-alloy was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for compositional and structural analysis. The alloy exhibited superior hydrogen absorption and desorption behavior with 3.2 wt% absorption within 1 min at 573 K and about 3 wt% desorption within 5-10 min at 573 K. This favorable behavior of Mg-Ni compound for the hydrogen storage is due to the specific nanostructure of the material. The low activation energy values and favorable thermodynamics indicate that the prepared Mg-Ni alloy is an attracting material for hydrogen storage applications. 相似文献
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Motoki Shimada Hisashi Tamaki Eiji Higuchi Hiroshi Inoue 《Journal of Materials Science》2013,48(20):7312-7319
To improve kinetics for hydrogen absorption of Mg and hydrogen desorption of MgH2, ternary composites were prepared from MgH2, Ni and Si or Ni2Si by a mechanochemical technique. The X-ray diffraction spectra of the resultant ternary composites after the initial hydrogen desorption treatment at 400 °C in vacuum suggested that in all composites the nanocrystalline Mg2Ni would be formed in the intergrain region between Mg and Ni components, while in the MgH2–Ni–Si composite the nanocrystalline Mg2Si would also be formed in the intergrain region between Mg and Si components. However, Ni2Si did not form any alloys with Mg. The hydrogen absorption rate at 250 °C for the MgH2–Ni–Ni2Si composite was comparable to that for the MgH2–Ni and MgH2–Ni–Si composites, while the hydrogen desorption rate at 250 °C decreased in the order of MgH2–Ni > MgH2–Ni–Ni2Si > MgH2–Ni–Si. In contrast, the hydrogen desorption rate at 220 °C for the MgH2–Ni–Ni2Si composite was faster than that for the MgH2–Ni composite, suggesting that Ni2Si was a key material in the improvement of hydrogen desorbability at lower temperatures. Moreover, the most plausible reaction model and the rate-determining process for hydrogen absorption and desorption at 250 °C were determined. 相似文献
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M. Jurczyk 《Journal of Materials Science》2004,39(16-17):5271-5274
Nanocrystalline TiFe- and Mg2Ni-type alloys were prepared by mechanical alloying followed by annealing. The structure and electrochemical properties of these materials were studied. The properties of hydrogen host materials can be modified substantially by alloying to obtain the desired storage characteristics. It was found that the respective replacement of Fe in TiFe by Ni and Mn improved not only the discharge capacity but also the cycle life of these electrodes. On the other hand, a partial substitution of Mg by Mn in Mg2?x M x Ni alloy leads to an increase in discharge capacity, at room temperature. Furthermore, the effect of the nickel and graphite coating on the structure of the nanocrystalline alloys and the electrodes characteristics were investigated. In Mg2Ni-type alloy mechanical coating with graphite effectively reduced the degradation rate of the studied electrode materials. 相似文献
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Ca3-xMg2+xNi13合金的储氢性能 总被引:2,自引:0,他引:2
为了弄清Mg含量对Ca3Mg2Ni13型化合物结构参数和储氢性能的影响,利用X射线衍射研究了Ca3-xMg2+x,Ni13(x=0.5,1.0和1.5)合金的相结构,并采用Sieverts型设备测量了其P-C-T曲线.研究表明,Mg在Ca3Mg2Ni13型化合物中的最大固溶度接近于Ca1.5Mg<,3.5>Ni13合金中的Mg含量.固溶的Mg含量增加导致化合物点阵常数减小,这可以有效地改善吸放氢热力学性能,其中Ca2Mg3Ni13吸、放氢的焓变分别为-28,30 kJ/mol H2.此外,Ca2Mg3Ni13在吸放氢循环过程中不发生氢致非晶化和氢致分解,因而具有良好的循环稳定性. 相似文献
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In this paper, we present the hydrogen storage properties of Mg-Cd alloys prepared by ball milling. Mechanical alloying of a mixture of Mg and Cd elemental powders containing up to 20 at.%Cd leads to a magnesium solid solution. The lattice spacings of the hcp Mg phase shrink with dissolution of cadmium atoms in Mg. The mechanically alloyed pure Mg-Cd alloys are very difficult to activate for hydrogen absorption. However, if vanadium and graphite additives are added, a Mg(Cd)-V-C nanocomposite forms after ball milling and the activation then becomes very easy. The hydrogen absorption/desorption kinetics are very fast. The plateau pressure and slope of hydrogen absorption/desorption increase, while the hydrogen storage capacity decreases with increasing cadmium content. 相似文献