Synthesis, crystal growth and mechanical properties of lead molybdate

Single crystals of PbMoO4 were grown by Czochralski method. The growth behaviour has been studied by taking into consideration the different parameters such as seed rotation rate, pulling rate and the axial temperature gradient above the melt level. It was found that the crystal-melt interface shape is always convex despite low axial temperature gradient and high seed rotation rate and is attributable to the fact that the crystal is transparent in the IR region and hence to internal radiant heat transfer through the crystal. To study the chemical entities, the powder sample was examined with the FTIR spectroscopic method. Differential thermal analysis confirmed the melting point and the composition. Optical microscopic observation of single crystals revealed gas bubbles in the crystals grown at faster pulling rate and strain induced surface cracks upon heat treatment in the crystals grown with more convex crystal-melt interface shape. Microhardness studies were also performed on the as grown and heat-treated samples and the values of microhardness and fracture toughness were calculated. (C) 1997 Elsevier Science S.A.