The mass transfer mechanisms in polycrystalline alumina wafers serving as models for anti-oxidation films were investigated by evaluating oxygen permeability at 1873 K using ¹⁸O₂ as a tracer. The grain boundary (GB) diffusion coefficients for oxygen in the vicinity of the higher oxygen partial pressure (P_O2(hi)) surface were directly determined from the secondary ion mass spectrometry line profile for each GB, obtained from cross-sections of the exposed wafer. An especially interesting result was that, under dry conditions, the oxygen GB diffusivity obtained with an applied oxygen potential gradient (dμ_O) was significantly lower than that associated with oxygen self-diffusion in the absence of a dμ_O. Moreover, the contribution of electronic conductivity near the P_O2(hi) surface was increased upon applying a dμ_O. The addition of H₂O to the P_O2(hi) environment in conjunction with a dμ_O accelerated oxygen GB diffusion, while the presence of D₂O retarded the diffusivity compared to that observed under dry conditions. However, in the absence of a dμ_O, the oxygen GB diffusivity was essentially equal to that under dry conditions. The dissociative adsorption reactions of H₂O or D₂O over the entire P_O2(hi) surface appear to greatly affect the diffusivity of oxygen and aluminum on the surface and along the GBs in the vicinity of the surface.

通过使用¹⁸ O ₂作为示踪剂评估1873 K下的氧气渗透率，研究了用作抗氧化膜模型的多晶氧化铝晶片中的传质机理。直接从每个离子的二次离子质谱谱线轮廓确定高氧分压（P _O2（hi））表面附近氧气的晶界（GB）扩散系数，从暴露的横截面获得威化饼。一种特别有趣的结果是，在干燥条件下，所施加的氧气势梯度中获得的氧扩散率GB（dμ _ö）比用在不存在dμ的氧自扩散相关联的被显著降低_ö。此外，在P附近的电子传导性的贡献_O2（HI）表面在施加dμ增加_Ò。加入H的₂ O操作在P _O2（HI）的环境连同dμ _ö加速氧GB扩散，而d的存在₂ ö相比，在干燥条件下观察到阻碍了扩散性。然而，在不存在dμ的_Ô，氧GB扩散是在干燥条件下基本上相等。H ₂ O或D ₂ O在整个P _O2上的解离吸附反应（hi）表面似乎极大地影响了表面上以及表面附近GBs上的氧气和铝的扩散率。