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聚四氟乙烯真空加压浸渍改性柔性石墨垫片研究
PTFE Vacuum Pressure Impregnation Modification Flexible Graphite Gasket
【摘要】 为了扩大柔性石墨垫片在苛刻工况中的应用范围,本文选用聚四氟乙烯为浸渍剂,采用液相浸渍法对柔性石墨垫片进行改性,并通过单因素条件试验确定最佳浸渍剂配比和浸渍工艺。结果表明,在浸渍真空度为-0.095 MPa、真空加压压强为0.65 MPa、浸渍次数为2次、浸渍时间为30 min、浸渍浓度为60%(质量分数)、浸渍温度为35℃时可获得最佳浸渍效果,浸渍后的柔性石墨垫片泄漏率为2.03×10-4 cm3/s,增重率为4.39%,压缩率为32.17%,回弹率为22.34%。SEM和EDS测试结果表明:聚四氟乙烯乳液通过浸渍向石墨片层层间缝隙内部渗透,有效地填充了柔性石墨垫片内部片层和颗粒间的空隙,改善了垫片的渗透泄漏。碳元素主要以石墨形式均匀分布,氧元素以杂质形式均匀分布在石墨内部,氟元素分布较为集中。
【Abstract】 In order to expand the application range of flexible graphite gasket in harsh working conditions, polytetrafluoroethylene(PTFE)was selected as impregnating agent, and flexible graphite gasket was modified by liquid phase impregnation method. The optimum impregnating agent ratio and impregnation process were determined by single factor condition experiment. The results show that the best impregnation effect can be obtained under the conditions of impregnation vacuum degree of-0.095 MPa, vacuum pressure of 0.65 MPa, impregnation times of two times, impregnation time of 30 min, impregnation concentration of 60%(mass fraction) and impregnation temperature of 35 ℃, and the leakage rate of impregnated flexible graphite gasket is 2.03×10-4 cm3/s, the weight gain rate is 4.39%, the compression rate is 32.17%, and the rebound rate is 22.34%. SEM and EDS test results show that polytetrafluoethylene emulsion penetrates into the gaps between graphite lamellae through impregnation, effectively filling the gaps between lamellae and particles in flexible graphite gasket, and improving the leakage of gasket. Carbon element is mainly distributed uniformly in the form of graphite, oxygen element is distributed uniformly in graphite as impurities, and fluorine element is concentrated.
【Key words】 flexible graphite; sealing gasket; impregnation modification; polytetrafluoroethylene; leakage rate; weight gain rate;
- 【文献出处】 硅酸盐通报 ,Bulletin of the Chinese Ceramic Society , 编辑部邮箱 ,2023年10期
- 【分类号】TQ127.11
- 【下载频次】6