Production, Sintering and Mechanical Properties of Ca₂MgWO₆, a New Complex Cubic Perovskite Ceramic

Abstract

In the present work we have carried out production and characterization of a new complex cubic perovskite ceramic Ca2MgWO6 to evaluate its application viability as inert material for petroleum industry. Ca2MgWO6 was produced by thermo-mechanical processing and calcinations at 1.200°C, using stoichiometric amounts of constituent chemicals CaCO3, MgO and WO3. The calcined material was examined by x-ray diffraction, which identified the phase formation Ca2MgWO6. Calcined material was powdered in a ball mill, compacted as circular discs and subjected to sintering at temperatures of 1.250, 1.300 and 1.350°C. The powders, both those employed in the calcined pellets as those produced by the mill, were characterized by size distribution. The sintered discs were characterized by SEM. The results showed that the ceramics sintered at 1.250°C presented better results in terms of microstructural features and mechanical properties for their possible application as inert material for petroleum industry.

Effect of A-Cation Radius on the Structure, Luminescence, and Temperature Sensing of Double Perovskites A2MgWO6 Doped with Dy3+ (A = Ca, Sr, Ba)

“…A few studies on the crystal structure of CMW, SMW, , and BMW have been published previously. BMW was reported as cubic , while CMW crystallized in monoclinic, ,,,,− orthorhombic or cubic . SMW showed stability of the tetragonal phase up to 40 GPa and revealed a continuous phase transition at 570 K, changing the symmetry from tetragonal to cubic .…”

“…BMW was reported as cubic 15 , 16 while CMW crystallized in monoclinic, 15 , 22 , 26 , 32 , 36 − 40 orthorhombic 41 or cubic. 20 SMW showed stability of the tetragonal phase up to 40 GPa 33 and revealed a continuous phase transition at 570 K, changing the symmetry from tetragonal to cubic. 34 Therefore, to obtain the accurate crystal structure of the synthesized samples, the Le Bail refinement method was applied.…”

“… 11 More importantly, a phase transition in Ba (2 – x ) Sr x MgWO 6 :Er,Yb resulted in an improvement in the maximum relative sensitivity of the thermometer, increasing from 0.8%/K to 0.9%/K, respectively. 11 While Ca 2 MgWO 6 (CMW) has been studied over the past few years, the main focus has been on ceramic fabrication 20 , 21 and optical thermometry based on the up-conversion luminescence of Er 3+ and Yb 3+22 . Surprisingly, the luminescent properties of rare-earth-ion-activated −Sr 2 MgWO 6 (SMW) remain unknown.…”