Prior studies have noted that gas nitriding has a considerable effect for wear resistance. The aim of this paper is to study the influence of gas nitriding time (12, 24, 36 and 48 h) in the wear behaviour of 42CrMo4 s...Prior studies have noted that gas nitriding has a considerable effect for wear resistance. The aim of this paper is to study the influence of gas nitriding time (12, 24, 36 and 48 h) in the wear behaviour of 42CrMo4 steel. It has been assessed by micro hardness, pin-on-disc tribosystem, and SEM through the nitrided layer for each nitriding time. The study relates to the performance of the compound layer and the diffusion layer with respect to adhesive wear. The results were analyzed in terms of the weight lost during wear, for nitrided steel with and without the compound layer, and for untreated steel. It has been observed that wear rate varies as a function of the tests conditions due to the presence of different wear mechanisms. Thus, for short tests conditions wear rate depends on two mechanisms: plastic deformation and adhesive wear, whereas for large tests conditions the mechanisms controlling wear rate are abrasive and oxidative wear. Furthermore, this study contains an analysis of the wear mechanisms of a nitrided part, founded on scanning electron microscopy (SEM) observations of the wear traces at various stages of the evolution of wear. The SEM examination of worn surfaces revealed signatures for the adhesion, abrasion, delamination and tribochemical (oxidative) modes of wear. This is an important issue for future research.展开更多
目的评估2种类型复合树脂水门汀与E.MAX铸瓷全冠的3年临床粘接效果。方法对154名接受E.MAX铸瓷全冠修复的患者进行为期3年的随访,共计218件冠修复体,使用的树脂粘接系统包括自酸蚀类复合树脂水门汀PANAVIA F,需使用ED-Primer预处理基牙...目的评估2种类型复合树脂水门汀与E.MAX铸瓷全冠的3年临床粘接效果。方法对154名接受E.MAX铸瓷全冠修复的患者进行为期3年的随访,共计218件冠修复体,使用的树脂粘接系统包括自酸蚀类复合树脂水门汀PANAVIA F,需使用ED-Primer预处理基牙表面和自粘接类复合树脂水门汀Rely X Unicem,粘接前均使用硅烷偶联剂预处理冠内粘接面。3年观察期间出现的修复体脱落和折裂均记为失败。记录失败情况并计算成功率。结果E.MAX铸瓷全冠与PANAVIA F和Rely X Unieem粘接的3年保存率分别为97.5%和96.0%。脱落失败均出現在后牙区有大面积树脂充填物的基牙上。结论在3年观察期内,自酸蚀类和白粘接类复合树脂水门汀粘接的E.MAX铸瓷全冠临床表现良好。展开更多
文摘Prior studies have noted that gas nitriding has a considerable effect for wear resistance. The aim of this paper is to study the influence of gas nitriding time (12, 24, 36 and 48 h) in the wear behaviour of 42CrMo4 steel. It has been assessed by micro hardness, pin-on-disc tribosystem, and SEM through the nitrided layer for each nitriding time. The study relates to the performance of the compound layer and the diffusion layer with respect to adhesive wear. The results were analyzed in terms of the weight lost during wear, for nitrided steel with and without the compound layer, and for untreated steel. It has been observed that wear rate varies as a function of the tests conditions due to the presence of different wear mechanisms. Thus, for short tests conditions wear rate depends on two mechanisms: plastic deformation and adhesive wear, whereas for large tests conditions the mechanisms controlling wear rate are abrasive and oxidative wear. Furthermore, this study contains an analysis of the wear mechanisms of a nitrided part, founded on scanning electron microscopy (SEM) observations of the wear traces at various stages of the evolution of wear. The SEM examination of worn surfaces revealed signatures for the adhesion, abrasion, delamination and tribochemical (oxidative) modes of wear. This is an important issue for future research.
文摘目的评估2种类型复合树脂水门汀与E.MAX铸瓷全冠的3年临床粘接效果。方法对154名接受E.MAX铸瓷全冠修复的患者进行为期3年的随访,共计218件冠修复体,使用的树脂粘接系统包括自酸蚀类复合树脂水门汀PANAVIA F,需使用ED-Primer预处理基牙表面和自粘接类复合树脂水门汀Rely X Unicem,粘接前均使用硅烷偶联剂预处理冠内粘接面。3年观察期间出现的修复体脱落和折裂均记为失败。记录失败情况并计算成功率。结果E.MAX铸瓷全冠与PANAVIA F和Rely X Unieem粘接的3年保存率分别为97.5%和96.0%。脱落失败均出現在后牙区有大面积树脂充填物的基牙上。结论在3年观察期内,自酸蚀类和白粘接类复合树脂水门汀粘接的E.MAX铸瓷全冠临床表现良好。
