试样面积比和形状对氢渗透及表观扩散系数的影响

EFFECT OF PERMEATION AREA RADIO AND SHAPE OF SPECIMEN ON HYDROGEN PERMEATION AND APMRENT DIFFUSION COEFFICIENT

采用Ｄｅｖａｎａｔｈａｎ电池测渗氢电流时，试样面积比（氢渗透面积和试样总面积之比）及几何形状对测定结果有明显影响．当面积比小于某一临界值时，测不出氢渗透曲线，而且该临界值与试样几何形状有关．随试样面积比增大，测出的表观扩散系数也增大；相同面积比下测出的氢扩散系数与试样几何形状有关．

The effect of the ratio of permeation area to the specimen area ζ and the shape of the specimenon hydrogen permeation of copper has been studied using the Devanathan's double electrolytic cell. Theresults show that only when the permeation area ratio ζ exceeds a critical value ζc, which depends on thegeometric shape, can the hydrogen permeation curve and the apparent diffusion coefficient be measured.The ζc has the smallest value for a circular specimen and the highest value for a polygonal one. Theapparent diffusion coefficient measured increases with increasing permeation area ratio ζ. A circularspecimen with a large permeation area ratio is the most ideal one for hydrogen permeation test at roomtemperature.