화학공학소재연구정보센터
Journal of Materials Science, Vol.45, No.8, 2085-2089, 2010
The effect of thermodynamic properties of Me-Ti (Me = In, Sn, Ga, Au, and Ge) melts on the wetting of the CaF2 substrate
The effect of Ti additions on the wetting behavior of CaF2 by non-reactive liquid metals (In, Sn, Ga, Au, Ge) was investigated. Pure metals do not wet CaF2 while minor additions of Ti improve wetting. Small changes of the contact angle were observed in the CaF2/Au-Ti and CaF2/Ge-Ti systems, which are characterized by strong Me-Ti interaction in the melt, while considerable decrease of contact angle was obtained in the CaF2/In-Ti, CaF2/Sn-Ti and CaF2/Ga-Ti systems, which display a relatively weak Me-Ti interaction. According to a thermodynamic analysis and experiential observations, Ti does not react with the substrate to form condensed phases at the metal/CaF2 interface. Therefore, it was assumed that the mechanism of the wetting improvement is attributed to the Ti segregation at the interface. The results of the XPS analysis confirm a Ti enrichment of the region close to the interface, moreover, according to the high resolution XPS spectrum, obtained from this region, the position of the In4d peak has a chemical shift, which is typical for In-Ti intermetallic compounds. The XPS analysis does not provide sufficient evidence for the formation of the intermetallic interfacial layer at elevated temperature. Thus, further investigations have to be designed and conducted in order to clarify this issue.