Pressure dependence of negative thermal expansion in Zr2(WO4)(PO4)2

Negative thermal expansion materials can experience significant stresses when they are used in composites. Under ambient conditions Zr-2(WO4) (PO4)(2) displays anisotropic negative thermal expansion (NTE) (alpha(upsilon)= -14.0(10) x 10(-6) K-1, alpha(a) = -7.9(5) x 10(-6) K-1, alpha(b) = 2.5(5) x 10(-6) K-1, alpha(c) = -8.7(2) x 10(-6) K-1 at 0 GPa). The effect of hydrostatic pressure on its thermal expansion characteristics was investigated by neutron diffraction between 300 and 60 K at pressures up to 0.3 GPa. No phase transitions were observed in the pressure and temperature range examined. The material was found to have a bulk modulus, B-0 of 61.3(8) GPa at ambient temperature, and unlike some other NTE materials, pressure had no detectable effect on thermal expansion (alpha(upsilon) = -14.2(8) x10(-6) K-1, alpha(a) = -7.9(3) x 10(-6) K-1, alpha(b) = 2.9(5) x 10(-6) K-1, alpha(c) = -9.2(2) x 10(-6) K-1 at 0.3 GPa). (C) 2009 Elsevier Ltd. All rights reserved.