高丽华,邓霞,彭浩然,章德铭.氧化钆改性铈酸镧热障涂层材料设计 及涂层抗热震性能研究[J].热喷涂技术,2020,12(4):22~28.
氧化钆改性铈酸镧热障涂层材料设计 及涂层抗热震性能研究
Preparation and Thermal Shock Resistanceof Gd2O3 Doped La2Ce2O7 Thermal Barrier Coatings
  
DOI:10.3969/j.issn.1674-7127.2020.04.003
中文关键词:  热障涂层  La2Ce2O7  抗热震性能  Gd2O3
英文关键词:Thermal barrier coatings (TBCs)  La2Ce2O7  thermal shock resistance property  Gd2O3
基金项目:
           
作者单位
高丽华 矿冶科技集团有限公司
特种涂层材料与技术北京市重点实验室
北京市工业部件表面强化与修复工程技术研究中心
邓霞 矿冶科技集团有限公司
特种涂层材料与技术北京市重点实验室
北京市工业部件表面强化与修复工程技术研究中心
彭浩然 矿冶科技集团有限公司
特种涂层材料与技术北京市重点实验室
北京市工业部件表面强化与修复工程技术研究中心
章德铭 矿冶科技集团有限公司
特种涂层材料与技术北京市重点实验室
北京市工业部件表面强化与修复工程技术研究中心
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中文摘要:
      La2Ce2O7(LC) 由于具有比 YSZ 更低的热导率、 更高的热膨胀系数和良好的高温相稳定性, 是一种极具前 景的热障涂层陶瓷材料。 但该材料热膨胀系数在 200~400℃温度区间存在异常下降现象, 从而引起涂层过早失效 的问题。 目前, 通过掺杂 Gd2O3 可有效解决 LC 低温段热膨胀系数下降的问题, 但是, Gd2O3 改性 La2Ce2O7 热障 涂层最优掺杂浓度及涂层性能还未见报道。 本文采用化学共沉淀法制备了三种不同浓度 Gd2O3 改性 La2Ce2O7 材 料 ((LaxGd1-x)2Ce2O7(x=0,0.1,0.2,0.3)), 研究了掺杂浓度对其热物理性能及相稳定性的影响, 采用等离子喷涂工艺 制备了(La0.8Gd0.2)2Ce2O7 (LGC)涂层, 研究了涂层的抗热震性能和涂层的失效机理。 研究结果表明: (La0.8Gd0.2)2Ce2O7 (LGC) 材料具有较低的热导率, 室温到 1400℃无相变, 并且经 1400℃长时间热处理无相变; 其制备的双陶瓷结 构 LGC/YSZ 热障涂层 1100℃热震次数可达到 109 次, 较未改性 LC/YSZ 热障涂层提升了大约 60%; 两种涂层的 失效模式相似, 均为陶瓷顶层烧结引起的片状剥落失效。
英文摘要:
      La2Ce2O7 (LC) has been evaluated as one of promising thermal barrier coating candidate ceramic materials due to lower thermal conductivity, better phase stability and larger thermal expansion coefficient than YSZ. However, the thermal expansion coefficients of LC show a sudden drop between 200℃ ~400℃ , which would lead to the formation of thermal stress during thermal cycles and finally resulting in the early failure of the coatings. In recent studies, it has been reported that the sudden drop of the thermal expansion coefficients can be improved by doping with Gd2O3. However, there is little knowledge about the optimum doping content and performances of the coatings. In this paper, (LaxGd1-x)2Ce2O7 (x=0,0.1,0.2,0.3) with single fluorite structure were synthesized by chemical precipitation. The thermal conductivity and phase stability results were compared. (La0.8Gd0.2)2Ce2O7 (LGC) coatings were prepared by plasma spray method. The thermal shock test was performed and its failure mechanism was also studied. The results showed that (La0.8Gd0.2)2Ce2O7 (LGC) had low thermal conductivity and good phase stability from room temperature to 1400 ℃ . Besides, after 100h heat treatment at 1400℃ , there was no phase transformation, indicating high temperature phase stability. Moreover, the corresponding double-ceramic-layer (DCL) LGC /YSZ TBCs had better thermal shock resistance ability than that of LC /YSZ TBCs, which was around 109 cycles at 1200℃ . However, the failure modes was similar to that of LC /YSZ TBCs, which was still layer-by-layer spallation in LGC ceramic layer due to the sintering of the ceramic coating.
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