Fabrication of Mg–Ni–Sn alloys for fast hydrogen generation in seawater. (23rd March 2017)

• Record Type: Journal Article
• Authors: Oh, SeKwon; Cho, TaeHee; Kim, MinJoong; Lim, JeongHoon; Eom, KwangSup; Kim, DoHyang; Cho, EunAe; Kwon, HyukSang
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 12(2017)
• Page Start: 7761
• Page End: 7769
• Publication Date: 2017-03-23
• Subjects: Magnesium -- Mg–Ni–Sn alloy -- Hydrolysis -- Hydrogen generation; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2016.11.138
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Mg-2.7Ni-x wt.% Sn(x = 0–2) alloys were fabricated to promote hydrogen generation kinetics of Mg-2.7Ni alloy. The Sn in Mg-2.7Ni-Sn alloys exists as Mg2 Sn phase at the grain boundary and solid solution at the Mg matrix. The Mg2 Sn at the grain boundary acts as the initiation site for pitting corrosion and the dissolved Sn in the alloy causes pitting corrosion by locally breaking the surface oxide film in the Mg matrix in seawater. The Mg-2.7Ni-1Sn alloy showed an excellent hydrogen generation rate of 28.71 ml min −1 g −1, which is 1700 times faster than that of pure Mg due to the combined action of galvanic and intergranular corrosion as well as pitting corrosion in seawater. As the solution temperature was increased from 30 to 70 °C, the hydrogen generation rate from the hydrolysis of the Mg-2.7Ni-1Sn alloy was dramatically increased from 34 to 257.3 ml min −1 g −1 . The activation energy for the hydrolysis of Mg was calculated to be 43.13 kJ mol −1 . Highlights: The Mg–Ni–Sn alloys were specially designed to fast generate H2 in seawater. The Mg2 Sn at the grain boundary acts as the initiation site for pitting corrosion. The dissolved Sn causes pitting corrosion by locally breaking the surface oxide film. H2 generation rate of Mg-2.7Ni-1Sn was 1700 times faster than that of pure Mg in seawater. Enhanced performance was attributed to pitting, galvanic and intergranular corrosion.