Properties of Zr-Ti-Ni thin film metallic glasses modified with minor SF6

Metallic glass, or bulk glassy alloy (BGA), is a kind of metal which is generally fabricated by extremely rapid quenching. Therefore, Metallic glasses are noncrystalline alloys lacking long-range atomic periodicity. Because of the absence of grain boundaries and disordered atomic structure, BMGs have some superior properties. However, poor ductility significantly restricts the application of BMGs. Due to easier fabrication, thin film metallic glass (TFMG) having all the advantages of BMGs has drawn lot of attentions. In this thesis, properties of fluorine and sulfur doped Zr-Ti-Ni thin film metallic glasses were studied. While sputtering with 0.3 sccm SF6, hardness of Zr-Ti-Ni TFMG with only about 6% fluorine was higher than Zr-Ti-Ni TFMG for two times. HRTEM proved that high electronegativity F would attract other atoms to form short range orders (SROs) or nanograins embedded in the amorphous matrix. SROs and nanograins would interlock with each other and thus gave rise to the maximum mechanical properties. Through XPS analysis, the potential bindings and compounds would be investigated. High electronegativity F bound with Zr or reacted with it to form ZrF4. Therefore, it could be speculated that clusters and nanograins indeed existed and might consisted of Zr and F atoms.