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采用感应熔炼、甩带结合机械球磨法制备了Mg67-xCaxNi33(x=0,5,10,15,20,at%)储氢合金。研究了Ca含量及制备工艺对合金相结构和储氢性能的影响。结果表明,制备工艺(熔炼,熔炼+球磨,熔炼+甩带+球磨)对储氢合金的物相组成影响不大,而含Ca的合金经过甩带后容易形成非晶。不含Ca的Mg67Ni33合金主要由Mg2Ni相组成,并含有少量的Mg相;随着Ca含量升高,合金中的Mg2Ni相逐渐减少,而MgNi2相和Mg2Ca相逐渐增加。当Ca含量增加到20at%时,Mg47Ca20Ni33则主要由MgNi2和Mg2Ca组成,几乎没有Mg2Ni生成。P-C-T测试结果表明,在573K下,Mg67-xCaxNi33合金的最大吸氢量随着合金中Ca含量的升高而降低,这主要是由于Mg2Ni相含量减少造成的。吸氢后的Mg67Ni33主要由Mg2NiH4组成,而含Ca合金吸氢后则主要由Mg2NiH4、CaH2和不吸氢的MgNi2相组成。
Mg67-xCaxNi33 (x = 0,5,10,15,20, at%) hydrogen storage alloy was prepared by induction melting and rejection combined with mechanical milling. The effects of Ca content and preparation process on the phase structure and hydrogen storage properties of the alloy were investigated. The results show that the preparation process (smelting, smelting + ball milling, smelting + rejection + ball milling) has little effect on the phase composition of the hydrogen storage alloy, while the alloy containing Ca is easily amorphous after the rejection. The Ca67-free Mg67Ni33 alloy is mainly composed of Mg2Ni phase and contains a small amount of Mg phase. With the increase of Ca content, the Mg2Ni phase decreases and the MgNi2 phase and Mg2Ca phase increase gradually. When Ca content increases to 20at%, Mg47Ca20Ni33 mainly consists of MgNi2 and Mg2Ca, almost no Mg2Ni is formed. The results of P-C-T test showed that the maximum hydrogen absorption of Mg67-xCaxNi33 alloy decreases with the increase of Ca content in the alloy at 573K, which is mainly attributed to the decrease of Mg2Ni phase content. Mg67Ni33 after hydrogen absorption is mainly composed of Mg2NiH4, while the hydrogen absorption of Ca-containing alloy is mainly composed of Mg2NiH4, CaH2 and MgNi2 phase which does not absorb hydrogen.