Fast formation of a black inner α-Al2O3 layer doped with CuO on Al–Cu–Li alloy by soft sparking PEO process,Journal of the American Ceramic Society

当前位置： X-MOL 学术 › J. Am. Ceram. Soc. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Fast formation of a black inner α-Al2O3 layer doped with CuO on Al–Cu–Li alloy by soft sparking PEO process
Journal of the American Ceramic Society ( IF 3.5 ) Pub Date : 2023-06-08 , DOI: 10.1111/jace.19240
Xiaorui He ₁ , Tian Feng _{1,

2} , Yulin Cheng ₁ , Panfeng Hu ₁ , Zhengzhou Le ₁ , Zihua Liu ₁ , Yingliang Cheng ₁

Affiliation

Forming high-temperature α-Al₂O₃ phase under soft sparking is an intriguing phenomenon in plasma electrolytic oxidation (PEO) of Al alloys, which contradicts the low energy input of the process. In this study, α-Al₂O₃ doped with black CuO is formed beneath an amorphous white outer layer on Al–Cu–Li alloy by PEO in a dilute silicate electrolyte under soft sparking. In comparison, reddish coatings with dominating γ-Al₂O₃ are formed under the conventional plasma discharges, although blackish inner layer with α-Al₂O₃ can also be exposed by heavily polishing the samples. In order to know the underlying mechanism, temperatures at the coating surface and the underlying substrate have been monitored by a thermocouple under the conventional and soft sparking PEO regimes, respectively. Interestingly, high temperatures are detected in the case of soft sparking rather than PEO with strong discharges. The formation of CuO, quartz, and cristobalite within the soft sparking coating also supports the existence of high temperature. Hence, the formation of α-Al₂O₃ under soft sparking can be resolved to the conventional thermal activation mechanism, without the need of seeking other plausible explanations. Thermal condition evaluation for soft sparking PEO suggests that values of the effective thermal conductivity during PEO process for the outer layer and the barrier layer at the coating/substrate interface might be lower than ∼0.05 and ∼0.0017 W m⁻¹ K⁻¹, respectively. It is believed that the amorphous structure of the outer and barrier layers effectively blocks the heat dissipation, facilitating the formation of a highly wear-resistant inner layer with α-Al₂O₃, CuO, and the other high-temperature species under soft sparking.

中文翻译：

通过软火花 PEO 工艺在 Al-Cu-Li 合金上快速形成掺杂 CuO 的黑色内层 α-Al2O3

在铝合金的等离子体电解氧化（PEO）过程中，在软火花下形成高温α-Al ₂ O _{3相是一个有趣的现象，这与该过程的低能量输入相矛盾。}在本研究中，在稀硅酸盐电解液中，在软放电条件下，通过 PEO 在 Al-Cu-Li 合金上的非晶态白色外层下方形成了掺杂有黑色 CuO 的α-Al ₂ O _{3 。}相比之下，在传统等离子体放电下形成了以 γ-Al ₂ O _{3为主的微红色涂层，尽管内层为 α-Al}₂ O _3发黑也可以通过严重抛光样品来暴露。为了了解潜在的机制，涂层表面和底层基材的温度分别在传统和软火花 PEO 条件下通过热电偶进行监测。有趣的是，在弱火花的情况下检测到高温，而不是在强放电的 PEO 情况下检测到高温。软火花涂层内 CuO、石英和方英石的形成也支持高温的存在。_{因此，α-Al 2} O ₃的形成软火花下的问题可以解决为传统的热激活机制，而不需要寻求其他合理的解释。对软火花PEO的热条件评估表明，PEO过程中涂层/基材界面处的外层和阻挡层的有效导热率值可能分别低于~0.05和~0.0017 W m ^-1 K ^-1。。据认为，外层和阻挡层的非晶结构有效地阻止了散热，有利于在软火花下与α-Al 2 O 3 、CuO和其他高温物质_形成高_耐磨内层。

更新日期：2023-06-08

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南