Elasticity of ScAlO3 at high pressure

ScAlO3 is a close structural analogue for MgSiO3-perovskite in terms of its molar volume, structural distortion and compressional behavior. Polycrysta lline specimens of ScAlO3, were synthesized in a 1000-ton multi anvil press at 10 GPa, 1470 K from two different starting materials; amorphous ScAlO3 and mixed oxides. Two well-sintered and fully-trans formed specimens were r ecovered with low porosities of 0.5 and 1.7%. Elastic wave-speeds of these two specimens have been determined up to 3 GPa at room temperature. The res ults indicate that for these specimens, partial derivative K/partial deriva tive P = 3.8 and partial derivative C/partial derivative P = 1.9. The press ure derivatives of elastic moduli for the polycrystalline ScAlO3 specimens are expected to be reliable within 10% using this well-established ultrason ic technique. This is demonstrated by comparing determinations of the elast icity of polycrystalline Al2O3, with the available single crystal data, The values of partial derivative M/partial derivative P of ScAlO3 are consiste nt with those determined for MgSiO3 perovskite from X-ray P-V study and ult rasonic measurement. (C) 2000 Elsevier Science B.V. All rights reserved.