Abstract

A multilayered TiAlSiN thin film consisting of alternating nanocrystalline Ti(Si)N and Al(Si)N nanolayers was deposited on steel by arc ion plating. The film composition was 26Ti–16.3Al–1.2Si–56.50N in at%. The film was corroded at 800–1000 °C for 4–100 h in N₂/0.1%H₂S gas to study its corrosion behavior in hostile (H, S)-containing environments. The corrosion was primarily governed by oxidation, because oxides of Ti and Al were much more stable than the corresponding sulfides. The oxygen source for oxidation was impurity oxygen in N₂/0.1%H₂S gas. Initially, a superficial Al₂O₃ scale formed. Soon, the scale developed into the outer TiO₂-rich layer and the inner Al₂O₃-rich layer, beneath which formed an oxygen affected zone. As corrosion progressed, Si tended to accumulate in the lower part of the inner Al₂O₃-rich layer owing to its thermodynamic nobility. Preferential oxidation of Al to Al₂O₃, formation of fine, dense Al₂O₃ and TiO₂ grains in the oxide scale, and strong Ti–Si, Al–N and Ti–N bonds in the TiAlSiN film caused the scale to grow quite slowly and suppressed fast inward diffusion of sulfur and hydrogen as well as fast outward diffusion of Ti, Al, and Si. Therefore, the film displayed good corrosion resistance at 800–900 °C for up to 100 h. However, it corroded completely, with partial scale spallation and whisker growth at 1000 °C for 50 h.

Graphic Abstract

中文翻译：

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多层TiAlSiN膜在N 2 /0.1%H 2 S气体中在800–1000°C下的腐蚀

摘要

通过电弧离子镀在钢上沉积多层TiAlSiN薄膜，该薄膜由交替的纳米晶Ti（Si）N和Al（Si）N纳米层组成。膜成分为26Ti–16.3Al–1.2Si–56.50N，按原子百分比计。该膜在N ₂ /0.1%H ₂ S气体中于800–1000°C腐蚀4–100 h，以研究其在不利的（H，S）环境中的腐蚀行为。腐蚀主要由氧化决定，因为Ti和Al的氧化物比相应的硫化物稳定得多。用于氧化的氧源是N ₂ /0.1％H ₂ S气体中的杂质氧。最初，形成了表面Al ₂ O ₃垢。很快，氧化皮发展为外层TiO ₂富氧层和内部富Al ₂ O ₃层，在其下方形成一个受氧影响的区域。随着腐蚀的进行，Si由于其热力学贵族性而倾向于在内部Al ₂ O ₃富集层的下部积聚。Al优先氧化为Al ₂ O ₃，形成细致密的Al ₂ O ₃和TiO ₂氧化物鳞片中的晶粒，以及TiAlSiN膜中牢固的Ti-Si，Al-N和Ti-N键使鳞片生长相当缓慢，并抑制了硫和氢的快速向内扩散以及Ti，Al的快速向外扩散和Si。因此，该膜在800–900°C的温度下长达100小时显示出良好的耐腐蚀性。但是，它完全腐蚀了，在1000°C持续50 h时出现了部分鳞片剥落和晶须生长。

图形摘要