V-Cr-Pd-Cu氢分离合金铸态组织与氢传输性能

发布时间：2018-01-13 05:27

本文关键词：V-Cr-Pd-Cu氢分离合金铸态组织与氢传输性能　出处：《哈尔滨理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：氢分离金属膜是氢气进行分离提纯的关键,开发廉价、抗氢脆性能优异、具有高渗氢性能的新型金属膜材料势在必得,无钯或少钯的氢分离合金膜目前备受关注。本文通过研究元素Cr和Pd对V基固溶体类氢分离合金膜微观组织和性能的影响,从而获得典型V-Cr-Pd合金成分,结合“多相构成、功能分担”的共晶型氢分离膜材料设计理念,在典型V-Cr-Pd合金中引入fcc-(Cu)固溶体相,开发了V-Cr-Pd-Cu四元合金膜材料。本文采用了电子扫描显微镜(SEM)、X射线衍射仪(XRD)、Sieverts装置、高精度渗氢设备等分析测试手段。V-Cr-Pd铸态合金均由单一的bcc-(V)固溶体相构成,元素Cr和Pd均匀固溶在合金中。V原子被Cr原子置换后晶格被压缩,Cr含量越多晶格被压缩程度越大,bcc-(V)固溶体相的形貌由块状变成了蠕虫状。Pd可缓解晶格被压缩的程度,若元素Pd和Cr含量比例适中,几乎可消除晶格的压缩,得到bcc-V晶格参数与纯V一致的典型合金成分,即V-5Cr-5Pd合金成分。Pressure-Composition-Temperature(PCT)曲线表明,氢在V固溶体合金中的溶解是放热反应,各合金膜片的氢溶解度随温度的升高而下降,且在低平衡压时,温度对合金氢溶解度的影响十分显著。当合金中固溶Cr和Pd后,合金的吸氢量和氢扩散系数K都降低,固溶量越大,下降程度越明显。另外,元素Cr和Pd降低合金氢溶解的机理不同,且元素Pd降低合金氢溶解的能力要比Cr的强。V-7Cr-3Pd合金虽然渗氢速率优异但因渗氢过程中吸氢量较大,发生氢脆而导致膜片破裂。通过对V_(30)Cu_(70-x)Cr_x合金铸态微观组织和氢传输性能的研究发现,Cu-V合金可以形成与Cu-Nb超导合金类似具有非常合理的微观组织,符合氢分离膜材料设计理念,在该两相结构中,bcc-(V)固溶体相为渗氢相,是氢扩散通道,而fcc-(Cu)固溶体仅作为支撑相,不影响bcc-(V)固溶体相的各项性能,因此可以确定V-Cu合金设计理念的正确性。在V-5Cr-5Pd合金成分的基础上,引入fcc-(Cu)固溶体,开发出了(V-5Cr-5Pd)_(90)-Cu_(10)合金。随着Cu含量的降低,其合理的两相结构仍然存在。(V-5Cr-5Pd)_(90)-Cu_(10)合金在保持优异渗氢性能的同时其抗氢脆性能也非常突出。
[Abstract]:Hydrogen separation metal membrane is the key to the separation and purification of hydrogen. A new type of metal membrane material with excellent hydrogen embrittlement resistance and high hydrogen permeability is needed. Hydrogen separation alloy membranes without or without palladium have attracted much attention. In this paper, the effects of Cr and PD on the microstructure and properties of V-base solid solution-like hydrogen separation alloy membranes were studied. Thus, the design concept of eutectic hydrogen separation membrane material was obtained, which was composed of typical V-Cr-Pd alloy, combined with "multi-phase composition, function sharing". The V-Cr-Pd-Cu quaternary alloy membrane material was developed by introducing fcc-Pd-Cu) solid solution phase into typical V-Cr-Pd alloy. In this paper, the electron scanning microscope (SEM) was used to prepare the V-Cr-Pd-Cu quaternary alloy membrane material. X-ray diffractometer (XRD) Sieverts apparatus and high precision hydrogen permeation equipment. V-Cr-Pd as-cast alloys are all composed of a single Bcc-V) solid solution phase. The more Cr and PD atoms in the alloy were replaced by Cr atoms, the more the lattice was compressed. The morphology of bcc-V) solid solution phase changed from block to wormlike. PD can alleviate the compression of lattice. If the proportion of PD and Cr is moderate, the compression of lattice can be almost eliminated. The typical alloy compositions with the same lattice parameters as pure V have been obtained. That is, the composition of V-5Cr-5Pd alloy. Pressure-Composition-TemperaturePd (PCT) curve shows. The dissolution of hydrogen in V solid solution alloy is an exothermic reaction, and the hydrogen solubility of each alloy film decreases with the increase of temperature, and at low equilibrium pressure. The effect of temperature on the hydrogen solubility of the alloy is very significant. When Cr and PD are dissolved in the alloy, the hydrogen absorption and hydrogen diffusion coefficient K of the alloy decrease, and the larger the solution amount, the more the decrease degree. The mechanism of decreasing hydrogen dissolution of alloy by Cr and PD is different. The hydrogen solubilization ability of elemental PD alloy is stronger than that of Cr alloy. V-7Cr-3Pd alloy has better hydrogen permeation rate, but the hydrogen absorption capacity is larger in the process of hydrogen permeation. Hydrogen embrittlement leads to the rupture of the membrane. The study on the microstructure and hydrogen transport properties of the as-cast VS _ (30) / CuS _ (70) C _ (+) C _ (x) C _ (x) C _ x alloy has been carried out. Cu-V alloy can form a very reasonable microstructure similar to that of Cu-Nb superconducting alloy, which accords with the design idea of hydrogen separation membrane material, in the two-phase structure. Bcc-V) solid solution phase is hydrogen permeation phase and hydrogen diffusion channel, while fcc-cu-Cu) solid solution is only used as supporting phase and does not affect the properties of bcc-V) solid solution phase. Based on the composition of V-5Cr-5Pd alloy, the solid solution of fcc-cu is introduced. The alloy of V-5Cr-5PdPdCon is developed, and the content of Cu decreases with the decrease of Cu content. The reasonable two-phase structure of the alloy still exists. The hydrogen embrittlement resistance of the V-5Cr-5PdCd-Sch _ (90) -Cu _ (10)) alloy is also very prominent while maintaining its excellent hydrogen permeation properties as well as its hydrogen embrittlement resistance.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.2;TQ116.2

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