tải 68 game bài

Mobile Navigation
Chemical Engineering
View Comments

This new stainless steel is ultra-resistant to corrosion

| By Mary Page Bailey

One of the major hindrances in saltwater electrolysis for “green”-hydrogen production is the cost of materials to construct electrolyzer components that can withstand an extremely corrosive saltwater environment. Currently, titanium coated with platinum or gold is usually required for such applications. However, a grade of stainless steel developed by researchers at the University of Hong Kong (HKU; ) exhibits much higher corrosion resistance than typical stainless steels, at a much lower cost than coated titanium.

The key to this new steel grade — called SS-H2 — is a sequential dual-passivation mechanism that imbues additional corrosion resistance in stainless steel. Typical stainless-steel manufacturing employs a single-passivation method whereby the oxidation of chromium forms a protective film on the surface of stainless steel. The corrosion resistance of chromium-passivated steel becomes limited at potentials around 1,000 mV, which is significantly lower than what is required for water oxidation, meaning that such traditional stainless steels are not suitable for water-splitting applications.

The new sequential dual-passivation method includes a secondary manganese film layer on top of the chromium-containing film. This manganese-focused approach was quite novel. According to HKU mechanical engineering professor Mingxin Huang, who led the research, “the prevailing view is that manganese impairs raw corrosion resistance of stainless steel.” However, he says, numerous atomic-level experimental results clearly indicated the passivation behavior of the steel’s manganese content in a highly corrosive chloride environment at potentials up to 1,700 mV. Essentially, the primary Cr passivation layer protects at lower potentials, while the manganese layer provides additional protection at higher potentials, where the chromium layer can collapse and cause transpassive corrosion.

The university has partnered with an industrial factory to produce several tons of wire based on SS-H2, and patents have already been granted in two countries, with several other applications pending.

68 game bài đổi thưởng tải app 8xbet Đăng nhập qh88 bk8vietnam bk8 casino