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Zr702表面激光熔覆FeCrAl涂层微观组织及性能研究
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作者 陈宁杰 李玉新 +2 位作者 张静 李日榜 田苗 《精密成形工程》 北大核心 2023年第4期176-185,共10页
目的优化激光熔覆工艺参数,制备综合性能良好的FeCrAl涂层,提高Zr702基体的表面性能。方法通过同轴送粉方式,利用激光熔覆技术在Zr702表面制备了FeCrAl涂层,采用配备能谱仪(EDS)的扫描电镜(SEM)、X射线衍射仪(XRD)、数字显微硬度计、高... 目的优化激光熔覆工艺参数,制备综合性能良好的FeCrAl涂层,提高Zr702基体的表面性能。方法通过同轴送粉方式,利用激光熔覆技术在Zr702表面制备了FeCrAl涂层,采用配备能谱仪(EDS)的扫描电镜(SEM)、X射线衍射仪(XRD)、数字显微硬度计、高速往复摩擦试验机及马弗炉研究了不同激光功率(1300、1400、1600、1800 W)与扫描速度(7、8、9 mm/s)对FeCrAl涂层成型质量、显微硬度、耐磨性及抗高温空气氧化性能的影响。结果从所制备涂层的宏观形貌及微观组织可以观察到,在激光功率为1600W、扫描速度为9 mm/s时,涂层成型质量最好。显微硬度测试结果表明,随着激光功率和扫描速度的增大,显微硬度呈减小趋势,但涂层显微硬度均高于Zr702基体,平均显微硬度约为基体的2.70~3.78倍。耐磨性能测试结果表明,涂层的磨损量小于Zr702基体,在激光功率为1600 W、扫描速度为7 mm/s时,磨损量最低。氧化结果表明,800℃氧化时涂层未表现出良好的防护作用,但在1000℃氧化时,涂层样品皆表现出优于Zr702基体的抗高温空气氧化性能。结论通过调整工艺参数,采用激光熔覆技术在Zr702表面制备FeCrAl涂层可改善Zr702基体的显微硬度、耐磨性及1000℃下的抗高温空气氧化性能。 展开更多
关键词 激光熔覆 FECRAL 显微硬度 磨损性能 高温氧化 工艺参数
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SPATIAL-TEMPORAL CHANGES AND TRENDS OF AGEING IN CHINA 被引量:1
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作者 WANG Wu-yi ZHANG li +3 位作者 li Hai-rong li ri-bang YANG lin-sheng liAO Yong-feng 《Chinese Geographical Science》 SCIE CSCD 2005年第3期200-205,共6页
This study focuses on the development stages of ageing and its regional differences in China based on examination of official statistics and documents. The development of ageing in China has experienced three major st... This study focuses on the development stages of ageing and its regional differences in China based on examination of official statistics and documents. The development of ageing in China has experienced three major stages. Firstly, in the 1950s, low coefficient of elderly population (over 65 years) paced up to primary adult type. Secondly, there was a deeply drop of the elderly population because of natural disaster and political factors in the 1960s. Thirdly, from the 1970s to the end of 20th century, the constant increasing of elderly coefficient made China close to elderly society. With statistic data of population, Logistic model is used to simulate the future development of ageing, and two characteristics of development of ageing are presented. Firstly, as for ageing from 2005 to 2050, the elderly coefficient will grow up significantly from 8.48% to 16.30%. Secondly, after 2025, the increasing rate of elderly coefficient will slow down gradually. The regional differences of elderly population in China can be summarized as follows: 1) the eastern China possesses higher elderly coefficient and huger elder population than the western China; 2) about 47.4% of municipalities and provinces in the eastern China become elderly especially Shanghai, Zhejiang Province, Jiangsu Province, Beijing, Tianjin and Shandong Province; 3) ageing intensity is higher in rural area than urban area but getting close each other, and there are more elderly people in rural area than in urban area. Therefore, these will arose aged care problems, and it becomes important issue to establish the social security system in rural areas as soon as possible for elderly people. 展开更多
关键词 ageing ageing in rural area China
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