Calibration method for magnetic probes interfacial shear rheometers magnetic needle

摘要

The invention relates to a calibration method for magnetic probes for magnetic needle interfacial shear rheometers, comprising: taking measurements (202) of the movement of the magnetic probe (14) in a film-free water-air interface within a range of frequencies ω; obtaining (204) the deformation/force amplitude ratio AR(ω) and the phase difference δ(ω) between the voltage σ applied to the coils (3) of the rheometer (9) and the surface deformation γ produced by the movement (d) of the magnetic probe (14); setting initial values for the unit conversion constant C and the effective elastic constant of the oscillator k; obtaining the speed profile in the sub-phase (206) by numerically solving the speed field equations; obtaining (210) a distance D(Cj, kj) between the theoretical deformation/force amplitude ratio ART ratio and the experimental deformation/force amplitude ratio ARE for different values of C and k; selecting (212) the pair (Cmin, kmin) that minimises the distance D(Cj, kj).