[Lecture] Hydrogen safety:basic science of hydrogen embrittlement & prevention of hydrogen embrittlement


Part I:Basic science of hydrogen embrittlement
Time:October 22,14:30—16:30

Part II:Prevention of hydrogen embrittlement
Time:October 29,14:30—16:30

Speaker:Prof. Kiyoshi Yokogawa(National Institute of Advanced Industrial Science and Technology, Japan)
Online meeting venue: Tencent meeting (Room ID: 440 314 221)

[Introduction of the lecture]
Basic science of hydrogen embrittlement
Hydrogen energy is expected to improve the climate of the Earth. New hydrogen technology, in particular fuel cell vehicle (FCV) using high-pressure hydrogen storage, is developed. Hydrogen embrittlement (HE) of metallic materials to be used in hydrogen production, storage, transportation and utilization is important for public safety of not only hydrogen energy industry but also current chemical industry, oil refinery and ammonia synthesis using hydrogen. HE was discovered in 19th century, since then, many studies have been conducted. HE is classified into 3 categories, one is internal reversible HE, another is hydrogen gas embrittlement, the other is hydrogen reaction embrittlement. HE evaluation methods, i.e. mechanical testing, hydrogen diffusion, hydrogen analysis, and computational calculations are shown with our experiences. Based on these studies, several HE mechanisms have been proposed. Main mechanisms, i.e. hydrogen-enhanced localized plasticity theory (HELP) and hydrogen-enhanced strain-induced vacancy theory (HESIV) are described in details.

Prevention of hydrogen embrittlement
Fuel cell vehicle (FCV) is developed and commercially available in the market. FCV uses high-pressure hydrogen storage tank on board and hydrogen station also supplies high-pressure hydrogen into FCV. Application of HE for FCV and hydrogen station to prevent the accidents is discussed, i.e. hydrogen compatibility and hydrogen suitability are introduced to establish the mechanical design for high-pressure hydrogen storage.Hydrogen has been used in current chemical industry, oil refinery and ammonia synthesis from early 20th century.Many accidents have occurred in the industries, thus the application of HE is discussed to prevent the accidents, i.e. Nelson diagram for hydrogen attack and the strength limit of the component materials for delayed fracture are described in details.

Announced by the School of Mechanical and Automotive Engineering