Acta Phys. -Chim. Sin. ›› 1988, Vol. 4 ›› Issue (05): 558-560.doi: 10.3866/PKU.WHXB19880524

• Note • Previous Articles    

XPS STUDY OF THE THERMAL STABILITY OF NIOBIUM SURFACE OXIDES

Zhao Liangzhong   

  1. Institute of Chemistry; Academia Sinica
  • Received:1987-05-12 Revised:1988-03-19 Published:1988-10-15
  • Contact: Zhao Liangzhong

Abstract: XPS studies show that the dominant surface oxide is Nb_2O_5 for air exposed Nb metal at both room temperature and 300 ℃. The thickness of the room temperature Nb_2O_5 formed by 18 hours air exposure is less than the photoelectron escape depth. The room temperature Nb_2O_5 can be converted into Nb metal after heating the sample in vacuum at 350 ℃ for 30 minutes. If the surface Nb_2O_5 is formed at above 300 ℃, however, it can not be converted into Nb metal after heating the sample in vacuum at 350 ℃ for as long as 4 hours. It is suggested that the very thin room temperature surface Nb_2O_5 can differ from the bulk Nb_2O_5 on thermodynamical property.