Microstructure and hot corrosion behavior of Al-Si-Hf coating on new γ′-strengthened cobalt-based superalloy
Microstructure and hot corrosion behavior of Al-Si-Hf coating on new γ′-strengthened cobalt-based superalloy
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DOI：
10.1016/j.surfcoat.2020.126519
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发表时间：
2020-10
影响因子：
5.4
通讯作者：
X. Qi;Q. Hou;Mingyue Chen;Simin Zhu;Meifeng Li;Chungen Zhou
中科院分区：
文献类型：
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作者：
X. Qi;Q. Hou;Mingyue Chen;Simin Zhu;Meifeng Li;Chungen Zhou
采用包渗碳法在新型γ'强化钴基高温合金上沉积Al-Si-Hf涂层。涂层由外层和扩散区组成，外层由分散有Al5Co2相的AlCo相组成。研究了 Al-Si-Hf 涂层在 900 °C 下暴露于 75 wt% Na2SO4 和 25 wt% NaCl 中 100 小时的热腐蚀行为。总质量增加仅为 0.29 mg/cm2。这表明 Si 的添加促进了 Al2O3 氧化皮的形成，并提供了相对于熔盐稳定的 SiO2。 Hf改性通过抑制Al离子向外扩散降低了氧化铝氧化皮的生长速率，并通过钉扎效应提高了氧化皮的附着力。
An Al-Si-Hf coating was deposited on the new γ′-strengthened cobalt-based superalloy using pack cementation method. The coating was composed of an outer layer consisting of AlCo phase dispersed with Al5Co2phase and a diffusion zone. The hot corrosion behavior of the Al-Si-Hf coating exposed to 75 wt% Na2SO4and 25 wt% NaCl at 900 °C for 100 h was studied. The total mass gain was only 0.29 mg/cm2. It is suggested that the addition of Si facilitated the formation of the Al2O3scale and contributed stable SiO2against the molten salts. Hf modification reduced the growth rate of the alumina scale by restraining Al ions outward diffusion, and improved the adhesion of the oxide scale by providing pinning effect.