Difúze vodíku v moderních konstrukčních ocelích používaných v automobilovém průmyslu

Abstract

The task of this bachelor thesis is to determine the diffusion coefficients in modern structural steels used in the automotive industry. These are specifically TRIP 800 steel type C-Mn-Si and DP 600 steel. Samples of these steels were obtained from 1.5 mm thick sheets, where flat discs with a diameter of 20 mm were electrospark cutted. The discs were then thinned on semi-automatic metallographic grinders to a thickness of about 0.5 mm. The output sides of all samples were subjected to electrochemical coating by palladium to prevent recombination of hydrogen to molecules on the output side during subsequent electrochemical permeation. Electrochemical hydrogen permeation was performed using a technique developed by Devanathan and Stachurski, where individual samples are clamped between two glass cells. The diffusion coefficients themselves were obtained from the permeation curves using the "time lag" method.