表面氧化层对低碳钢氢渗透行为的影响

EFFECTS OF SURFACE OXIDE LAYER ON HYDROGENPERMEATION BEHAVIOUR IN LOW-CARBON STEEL

利用气相氢渗透技术，测定了＃１０碳钢表面镀Ｐｄ和预氧化两种状态（在８０－３３０℃温度范围内）的有效氢渗透率和扩散系数，结果表明：低于１５０℃，表面氧化层（主要为Ｆｅ３Ｏ４）对氢在钢中的渗透有明显的阻碍作用，有效氢渗透率降低约１个数量极，扩散系数降低３－４倍，但在１８０℃，１０ｋＰａ氢压力的条件Ｆ，表面氧化层开始被还原、氢渗透逐步回复到由钢中的体扩散所控制．氢在氧化钢中的渗透速率满足Ｓｉｅｖｅｒｔ定律．

Hydrogen permeabilities and diffusivities in # 10 carbon steel coated with Pd andpre-oxidized were determined using the gaseous permeation technique over the temperature rangeof 80 to 330℃. For temperature below 150℃, oxide scale had a marked barrier effect on hydrogenpermeation, and the effective Permeability was reduced by about 1 order of magnitude, whereasthe effective diffusivity was reduced by a factor of 3 to 10. Under the hydrogen pressure of 10kPaat 180℃, oxide scale began to be reduced partially. With the progress of reduction process,hydrogen permeability was gradually close to that under Pd-coated condition and the permeationprocess was controlled again by bulk diffusion. It was also found that in the case of oxidized steel,the applied pressure dependence of the hydrogen permeation rate obeyed Sievert's law.