A critical review and experimental analysis of the equation recommended by ASTM G148-97 and ISO 17081: 2004 for the calculation of the hydrogen diffusivity in metals and alloys

作者：Carualho J P D; Vilar E O^*; Araujo B A

来源：International Journal of Hydrogen Energy, 2017, 42(1): 681-688.

DOI：10.1016/j.ijhydene.2016.10.127

• Hydrogen permeation
• Fick's second law
• Sigmoid function
• API 5L X65
• API 5L X70
• ASTM G148-97
• ISO 17081: 2004

Since its discovery in 1864 by Cailletet [1], hydrogen embrittlement of metals has been the target of several investigations. In 1962 Devanathan and Stachurski [2], developed an electrochemical technique for hydrogen permeation. There are now three methods to produce hydrogen: galvanostatic, potentiostatic and under open circuit potential in an acid medium (OCPAc). Regulations in Refs. [3] and [4] standardized hydrogen permeation only by the potentiostatic method. In the present work an experimental methodology for OCPAc procedure was developed. The authors conclude that the equation of diffusivity proposed by ISO 17081 and ASTM 0148-97 [3] and [4] can lead to underestimated diffusivity values. The authors conclude the mathematical model proposed for the OCPAc method presented a satisfactory fit to the experimental data. Diffusivity values were calculated not only for this case but also for all other methods. However, to evaluate and explore the limits of the proposed methodology, the authors recommend its use with other metals and alloys.

• 出版日期2017-1-5