对110 k V交联聚乙烯(XLPE)电缆绝缘在100℃和160℃进行加速热老化实验,研究不同温度热老化条件下XLPE绝缘热性能和力学性能的劣化规律。通过红外光谱分析(FTIR)和差示量热扫描分析(DSC)表征了热老化试样中抗氧化剂的含量;通过X射线衍射...对110 k V交联聚乙烯(XLPE)电缆绝缘在100℃和160℃进行加速热老化实验,研究不同温度热老化条件下XLPE绝缘热性能和力学性能的劣化规律。通过红外光谱分析(FTIR)和差示量热扫描分析(DSC)表征了热老化试样中抗氧化剂的含量;通过X射线衍射(XRD)计算了不同热老化试样的结晶度;通过热重分析(TGA)研究了热老化试样的热降解特性;通过拉伸实验研究了热老化试样的力学性能。结果表明:热老化引发的氧化反应导致XLPE试样中的抗氧化剂逐渐消耗。当抗氧化剂存在时,氧化反应被抑制,XLPE试样的热性能和力学性能并未明显劣化,甚至还出现了一定程度的提升。当抗氧化剂消耗完毕后,氧化反应快速进行,引发剧烈的分子链断裂,结晶度下降,导致热性能和力学性能快速劣化。相比100℃热老化试样,160℃热老化试样的热性能和力学性能劣化更快,这是由更快的氧化反应速率以及结晶区遭受到更严重的破坏导致的。展开更多
Thermal barrier coating(TBC) materials play important roles in gas turbine engines to protect the Nibased super-alloys from the high temperature airflow damage. High melting point, ultra-low thermal conductivity, larg...Thermal barrier coating(TBC) materials play important roles in gas turbine engines to protect the Nibased super-alloys from the high temperature airflow damage. High melting point, ultra-low thermal conductivity, large thermal expansion coefficient, excellent damage tolerance and moderate mechanical properties are the main requirements of promising TBC materials. In order to improve the efficiency of jet and/or gas turbine engines, which is the key of improved thrust-to-weight ratios and the energysaving, significant efforts have been made on searching for enhanced TBC materials. Theoretically, density functional theory has been successfully used in scanning the structure and properties of materials, and at the same time predicting the mechanical and thermal properties of promising TBC materials for high and ultrahigh temperature applications, which are validated by subsequent experiments. Experimentally,doping and/or alloying are also widely applied to further decrease their thermal conductivities. Now, the strategy through combining theoretical calculations and experiments on searching for next generation thermal insulator materials is widely adopted. In this review, the common used techniques and the recent advantages on searching for promising TBC materials in both theory and experiments are summarized.展开更多
文摘对110 k V交联聚乙烯(XLPE)电缆绝缘在100℃和160℃进行加速热老化实验,研究不同温度热老化条件下XLPE绝缘热性能和力学性能的劣化规律。通过红外光谱分析(FTIR)和差示量热扫描分析(DSC)表征了热老化试样中抗氧化剂的含量;通过X射线衍射(XRD)计算了不同热老化试样的结晶度;通过热重分析(TGA)研究了热老化试样的热降解特性;通过拉伸实验研究了热老化试样的力学性能。结果表明:热老化引发的氧化反应导致XLPE试样中的抗氧化剂逐渐消耗。当抗氧化剂存在时,氧化反应被抑制,XLPE试样的热性能和力学性能并未明显劣化,甚至还出现了一定程度的提升。当抗氧化剂消耗完毕后,氧化反应快速进行,引发剧烈的分子链断裂,结晶度下降,导致热性能和力学性能快速劣化。相比100℃热老化试样,160℃热老化试样的热性能和力学性能劣化更快,这是由更快的氧化反应速率以及结晶区遭受到更严重的破坏导致的。
基金国家自然科学基金项目(51378426)教育部新世纪优秀人才基金项目(NCET-11-0714)+4 种基金四川省省级建筑节能专项资金项目四川省科技创新苗子工程项目(2014-122)supported by the National Natural Science Foundation of China(51378426)the Program of Ministry of Education of China for New Century Excellent Talents(NCET-11-0714)the Special Funds for Building Energy Efficiency Projects in Sichuan Province
基金supported by the National Natural Science Foundation of China (No. 51602188)the Program for Professor of Special Appointment (Eastern Scholar)by Shanghai Municipal Education Commission (No. TP2015040)
文摘Thermal barrier coating(TBC) materials play important roles in gas turbine engines to protect the Nibased super-alloys from the high temperature airflow damage. High melting point, ultra-low thermal conductivity, large thermal expansion coefficient, excellent damage tolerance and moderate mechanical properties are the main requirements of promising TBC materials. In order to improve the efficiency of jet and/or gas turbine engines, which is the key of improved thrust-to-weight ratios and the energysaving, significant efforts have been made on searching for enhanced TBC materials. Theoretically, density functional theory has been successfully used in scanning the structure and properties of materials, and at the same time predicting the mechanical and thermal properties of promising TBC materials for high and ultrahigh temperature applications, which are validated by subsequent experiments. Experimentally,doping and/or alloying are also widely applied to further decrease their thermal conductivities. Now, the strategy through combining theoretical calculations and experiments on searching for next generation thermal insulator materials is widely adopted. In this review, the common used techniques and the recent advantages on searching for promising TBC materials in both theory and experiments are summarized.
