Ti_3SiC_2耐氢氟酸腐蚀性研究

Corrosion Resistance of Ti_3SiC_2 in Hydrofluoric Acid

在Ar气氛中,以TiH_2/Si/2Ti C复合粉体为原料,利用无压烧结技术在1500°C下保温3 h成功制备出高纯Ti_3SiC_2,并利用氢氟酸对Ti_3SiC_2粉体进行刻蚀,研究其耐腐蚀性。XRD检测结果表明,在常压下Ti_3SiC_2样品经氢氟酸腐蚀前后的物相没有发生变化,且不随反应时间和温度的变化而发生变化。但是,扫描电镜图片显示样品中存在一些二维片层和腐蚀孔洞,这表明HF与Ti_3SiC_2发生了部分刻蚀反应。由于Ti_3SiC_2与酸的反应活性依赖于Si与酸的反应活性,而Si与HF在常压下反应较慢,因此Ti_3SiC_2与HF反应较困难。然而,Ti_3SiC_2与HF在180°C水热条件下则能完全反应,晶体结构遭到破坏,这表明Ti_3SiC_2在常温常压下对HF具有良好的耐腐蚀性,而在水热条件下Ti_3SiC_2易受HF的腐蚀。

High pure Ti3SiC2was synthesized from TiH2/Si/2TiC mixtures by pressurelesssintering at1500°C for3h in Ar atmosphere,and the hydrofluoric acid corrosion resistance of theprepared Ti3SiC2was studied.The XRD results showed that the phase of Ti3SiC2do not change afterHF etched,and is little affected by reaction time and temperature in atmospheric pressure.However,there have some two-dimensional plates and corrosion holes in the samples as observed by SEM,suggesting that Ti3SiC2partials were etched by HF.The low reaction rate between Ti3SiC2and HFwas due to the fact that the reactivity of Ti3SiC2strongly depends on the reactivity of Si element withthe acid,and silicon reacted with HF was very slowly at atmospheric pressure.However,the crystalstructure of Ti3SiC2was completely destroyed after hydrothermal reaction with HF at180°C.Thissuggests that Ti3SiC2have good hydrofluoric acid corrosion resistance at atmospheric pressure,whereas Ti3SiC2is vulnerable at high temperature and high pressure.