材料期刊网

在Ti₄₀Zr₄₀Ni₂₀准晶合金中掺Pd制备了Ti₃₆Zr₄₀Ni₂₀Pd₄准晶合金, 利用X射线衍射(XRD)、金相(OM)、光电子能谱(XPS)、气固反应等对其组织结构和吸氘特性进行了研究. 结果表明, 在吸铸态下该合金形成了二十面体准晶相, 准晶格常数为0.5174 nm. 其热力学稳定性较差, 约400 ℃时转变为tI-Zr₂Ni与C14-TiZrNiPd晶体相. 室温下, 其吸氘能力为11.0 mmol/g(相当于 2.2%的吸氢质量分数), 吸氘速率达到0.030 s^-1, 准晶结构不变但准晶格膨胀5.5%. 添加的Pd起到催化作用, 与初始合金相比, Ti₃₆Zr₄₀Ni₂₀Pd₄准晶合金的活化与储氘能力明显提高.

Ti-Zr-Ni quasicrystals can absorb a large amount of hydrogen, so have strong application potential in the hydrogen energy field and international thermonuclear experimental reactor (ITER) program. However, the hydrogenation of the quasicrystals is often hindered and even poisoned due to their surface oxidation. To inhibit the oxidation, Pd has been selected, because of its catalysis to hydrogen absorption, as a minor alloying element in Ti-Zr-Ni quasicrystals. In this paper, the Ti₃₆Zr₄₀Ni₂₀Pd₄ alloy was designed and its thermal stability and room--temperature deuteration were studied with XRD, DSC, OM, XPS and gas--solid reaction measurement apparatus. The XRD result shows that a single icosahedral quasicrystal (IQC) phase with a quasilattice constant a_R=0.5174 nm was formed in the alloy by suction-casting method, which is metastable and transforms to conventional crystals tI-Zr₂Ni and C14-TiZrNiPd (MgZn₂ type) phase at about 400℃. The deuteration test below the transformed temperature indicates that the alloy can absorb deuterium up to a large concentration of 11.0 mmol/g (corresponding to 2.2%H, mass fraction) at room temperature after vacuuming and heating activation without any surface treatment. Once fully activated, the IQC can load deuterium rapidly with an absorption rate of\linebreak 0.030 s^-1 at ambient temperature, and has the quasilattice constant with about 5.5% expansion after two absorption cycles. The Ti₃₆Zr₄₀Ni₂₀Pd₄ IQC has better activation property and hydrogen capacity than the Ti₄₀Zr₄₀Ni₂₀ IQC, which shows the catalyzing function of Pd.