Cr对Cu-V氢分离合金组织与氢传输性能的影响

The effects of Cr on the microstructure and hydrogen transport properties of Cu-V hydrogen permeable alloy

氢分离金属膜是目前备受关注的一种用于氢气提纯的功能材料.为了获得综合性能优异且价格低廉的氢分离金属膜,本文借鉴"多相构成、功能分担"的设计理念,通过非自耗电弧熔炼炉制备合金,采用XRD、扫描电子显微镜等手段研究合金相组成及微观组织,采用课题组自主设计的仪器设备在不同温度和压力下进行氢溶解和氢渗透实验,开发了具有双相结构的新型Cu-V-Cr氢分离合金.结果发现:该合金微观组织中的bcc-(V)固溶体相起渗氢作用,是氢的主要扩散通道;而组织中的fcc-(Cu)固溶体相起提高塑性作用.合金化元素Cr主要固溶在bcc-(V)中,显著降低合金的氢溶解能力,大幅度提高抗氢脆性能,但同时也降低合金的氢扩散系数和渗氢性能.实验表明,具有双相结构的Cu-V-Cr氢分离合金有望达到氢溶解、扩散和渗透性能的良好匹配,从而同时实现优异的氢渗透性能与抗氢脆性能.

Hydrogen permeable metal membranes are a kind of important functional materials used for hydrogen separation and purification. In order to develop low cost membrane materials with comparable hydrogen permeation properties,experiments of hydrogen dissolution,permeation and diffusion were carried out under various pressures and temperatures by the self-developed equipments,based on the design concept of different phases displaying different functions. Ingots of model alloys were prepared by arc melting furnace, and microstructural and crystallographic analyses were performed in a scanning electron microscope,and X-ray diffractometry（XRD）. In this paper,new hydrogen permeable Cu-V-Cr alloys consisting of dual-phase structure,bcc-（V） and fcc-（Cu）solid solutions are developed. The bcc-（V） is mainly responsible for hydrogen permeation while the fcc-（Cu） solid solution is beneficial for the improvement in ductility. The addition of Cr,mainly distributed in bcc-（V）,reduces the hydrogen solubility of alloys and thus improves the hydrogen embrittlement resistance,but reduces hydrogen diffusivity and permeability. The results obtained here indicate that the Cu-V-Cr alloys with dual-phase structure are promising to reach an excellent balance among hydrogen solubility,diffusivity and permeability,and thus to achieve both high hydrogen permeability and embrittlement resistance.