Easydrop instrument

The microstructure of MgCa alloys was examined using a metallographic microscope (DMI5000 M, Leica, Wetzlar, Germany) equipped with a dedicated digital camera connected to a personal computer. Image analysis was performed using the Leica Application Suite software program. Prior to optical imaging, the samples were first mechanically abraded using a sequence of silicon carbide abrasive papers, followed by a final polishing step using 0.3 µm alumina suspension. Next, the samples were cleaned in alcohol and distilled water using an ultrasonic bath, and finally etched in a solution containing 12 g picric acid, 80 mL acetic acid, 350 mL ethanol, and 80 mL water.
X-ray diffraction (XRD) was employed for the identification the phase structure. XRD spectra were recorded using an X'Pert PRO MRD (PANalytical, Almelo, The Netherlands) diffractometer equipped with a Cu Kα anode, and the XRD patterns were scanned in the 30° ≤ 2θ ≤ 80° range.
Wettability of the surface preparations of the MgCa alloys was established by contact angle measurements. They were performed using an EasyDrop instrument (Kruss, Germany) controlled by a personal computer and specific software (Drop Shape Analysis, Kruss, Germany).