Role of thermally grown oxide and oxidation resistance of samarium strontium aluminate based air plasma sprayed ceramic thermal barrier coatings
Role of thermally grown oxide and oxidation resistance of samarium strontium aluminate based air plasma sprayed ceramic thermal barrier coatings
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DOI：
10.1016/j.surfcoat.2017.07.049
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发表时间：
2017-10
影响因子：
5.4
通讯作者：
T. Baskaran;S. Arya
中科院分区：
文献类型：
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作者：
T. Baskaran;S. Arya
采用空气等离子喷涂工艺在NiCrAlY Inconel 718高温合金表面制备了铝酸锶钐（SSA）基陶瓷氧化物涂层。在氩气气氛中在1050 °C下在10、20和30 h的不同预氧化时间下控制热生长氧化物（TGO）厚度，对于30 h预氧化样品发现最高TGO厚度。在1050 °C下，随着预氧化时间的增加，预氧化样品的弹性恢复百分比增加（45%、48%和50%）。在空气中在1100 °C下对预氧化样品进行等温氧化测试15小时。在1100 °C预氧化30 h的SSA样品中，抛物线氧化速率常数从6.08 × 10− 5降低到3.90 × 10− 5 mg 2cm − 4s− 1（从10到20 h），然后增加到4.55 × 10− 5 mg 2cm − 4s− 1。SSA基热障涂层在1100 °C空气中氧化后的增重比传统的YSZ热障涂层低65%。截面SEM结果表明，SSA热障涂层的临界TGO厚度约为5.3 ~ 5.8 μm。SSA热障涂层的失效是由于在TGO和陶瓷涂层的界面处形成了SmAlO 3和尖晶石氧化物。
Samarium Strontium Aluminate (SSA) based ceramic oxide was synthesized and coated on a bond coated (NiCrAlY) Inconel 718 superalloy by air plasma spray (APS) process. Thermally grown oxide (TGO) thicknesses were controlled at different pre-oxidation times of 10, 20 and 30 h at 1050 °C in the argon atmosphere, the highest TGO thickness being found for 30 h pre-oxidized samples. The percentage elastic recovery of pre-oxidized samples increased (45, 48, and 50%) with an increasing pre-oxidation time at 1050 °C. The isothermal oxidation test was performed on pre-oxidized samples at 1100 °C for 15 h in air. The parabolic oxidation rate constant decreased from 6.08 × 10− 5to 3.90 × 10− 5mg2cm− 4s− 1(from 10 to 20 h) and then increased up to 4.55 × 10− 5mg2cm− 4s− 1for 30 h pre-oxidized SSA samples at 1100 °C. SSA based TBCs showed 65% lower weight gain as compared to conventional YSZ TBCs after oxidation at 1100 °C in air. Cross-sectional SEM results revealed that the threshold TGO thickness of SSA TBCs is about 5.3 to 5.8 μm. Failure of SSA TBCs was observed at the interface of TGO and ceramic top coat due to the formation of SmAlO3along with spinel oxides.