[ Hydrogen ]
[ Hydrogen ]
Professor Mingxin Huang and Dr Kaiping Yu .
Cr-based anti-corrosion alloys and has superior pitting resistance in seawater ; however , transpassive corrosion limits its application at higher potentials . By using a “ sequential dualpassivation ” strategy , Professor Huang ’ s research team developed the novel SS-H2 with superior corrosion resistance . In addition to the single Cr 2 O 3 -based passive layer , a secondary Mn-based layer forms on the preceding Cr-based layer at ~ 720 mV . The sequential dual-passivation mechanism prevents the SS-H2 from corrosion in chloride media to an ultra-high potential of 1700 mV . The SS-H2 demonstrates a fundamental breakthrough over conventional stainless steel .
Overcoming conventional limitations “ Initially , we did not believe it because the prevailing view is that Mn impairs the corrosion resistance of stainless steel . Mn-based passivation is a counter-intuitive discovery , which cannot be explained by current knowledge in corrosion science . However , when numerous atomic-level results were presented , we were convinced . Beyond being surprised , we cannot wait to exploit the mechanism ,” said Dr Kaiping Yu , the first author of the article , whose PhD is supervised by Professor Huang . From the initial discovery of the innovative stainless steel to achieving a breakthrough in scientific understanding , and ultimately preparing for the official publication and hopefully its industrial application , the team devoted nearly six years to the work . “ Different from the current corrosion community , which mainly focuses on the resistance at natural potentials , we specialises in developing highpotential-resistant alloys . Our strategy overcame the fundamental limitation of conventional stainless steel and established a paradigm for alloy development applicable at high potentials . This breakthrough is exciting and brings new applications .” Professor Huang said .
Industrial application prospects At present , for water electrolyser in desalted seawater or acid solutions , expensive Au- or Pt-coated Ti are required for structural components . For instance , the total cost of a 10-megawatt PEM electrolysis tank system in its current stage is approximately HK $ 17.8 million , with the structural components contributing up to 53 % of the overall expense . The breakthrough made by Professor Huang ’ s team makes it possible to replace these expensive structural components with more economically steel . As estimated , the employment of SS-H2 is expected to cut the cost of structural material by about 40 times , demonstrating a great foreground of industrial applications . “ From experimental materials to real products , such as meshes and foams , for water electrolysers , there are still challenging tasks at hand . Currently , we have made a big step toward industrialisation . Tons of SS- H2-based wire has been produced in collaboration with a factory from the Mainland . We are moving forward in applying the more economical SS-H2 in hydrogen production from renewable sources ,” added Professor Huang .
www . stainless-steel-world . net Stainless Steel World March 2024 39