High temperature viscosity measurements by the gas film levitation technique: Application to various types of materials

The objective of this paper is to show the potential of gas film levitation for noncontact viscosity measurements. Materials studied include oxide and metallic glasses, ceramics, and biphasic metallic alloys. After a brief presentation of the gas film levitator, the analysis procedure of the drop relaxation, both in the aperiodic and oscillating modes, is described in connection with existing hydrodynamic models. The uncertainty of the viscosity measurements ranges from 5 to 15%, depending on the type of materials. The surface tension and the mass density of the sample necessary to derive the viscosity can also be measured in the same experimental apparatus.