New ultra stainless steel for hydrogen production
A research project led by Professor Mingxin Huang at the Department of Mechanical Engineering of the University of Hong Kong ( HKU ) has made a brand-new breakthrough over conventional stainless steel and the development of stainless steel for hydrogen ( SS-H2 ).
Text and images by University of Hong Kong
This marks another major achievement by Professor Huang ’ s team in its ‘ Super Steel ’ Project , following the development of the anti-COVID-19 stainless steel in 2021 , and ultra-strong and ultra-tough Super Steel in 2017 and 2020 respectively . The new steel developed by the team exhibits high corrosion resistance , enabling its potential application for green hydrogen production from seawater , where a novel sustainable solution is still in the pipeline . The performance of the new steel in salt water electrolyser is comparable to the current industrial practice using Titanium as structural parts to produce hydrogen from desalted seawater or acid , while the cost of the new steel is much cheaper .
Pioneering dual-passivation mechanism Since its discovery a century ago , stainless steel has always been an important material widely used in corrosive environments . Chromium is an essential element in establishing the corrosion resistance of stainless steel . Passive film is generated through the oxidation of chromium ( Cr ) and protects stainless steel in natural environments . Unfortunately , this conventional single-passivation mechanism based on Cr has halted further advancement of stainless steel . Owing to the further oxidation of stable Cr 2 O 3 into soluble Cr ( VI ) species , tranpassive corrosion inevitably occurs in conventional stainless steel at ~ 1000 mV ( saturated calomel electrode , SCE ), which is below the potential required for water oxidation at ~ 1600 mV . 254SMO super stainless steel , for instance , is a benchmark among
38 Stainless Steel World March 2024 www . stainless-steel-world . net