heological characterisation was carried out with a controlledstress
rheometer, Physica MCR-501 (Anton Paar, Austria). Viscous
flow tests were performed applying a stepped shear rate ramp in a
shear rate range of 3 103
–102 s1 at 25 and 125 °C. Wall slip
phenomena usually observed in lubricating greases [43] was
avoided by using a plate–plate geometry (25 mm diameter, 1 mm
gap) with grooved surfaces. At least two repeats of each test were
performed on fresh samples.