The knowledge of the interdependence between the structural, thermal and el
ectric properties of oxide semiconductors contributes to widen their practi
cal application. In this work the thermal behaviour of WO3 and WO3/TiO2 pow
ders and thick films - studied by DSC - is compared with the results of X-r
ay diffraction (XRD) investigation in the temperature range 25-500 degreesC
. The X-ray analyses show a reversible phase transition (from gamma -WO3 in
to beta -WO3) both in WO3 and in WO3/TiO2. However, while in the WO3 the tr
ansition takes place between 300 and 400 degreesC, in the WO3/TiO2 system i
t is not complete even at 400 degreesC, during the measurement time. The ph
ase transition in the WO3 was identified between 320 and 360 degreesC also
by DSC, but in the bicomponent material no sharp transition could be detect
ed. This may mean that titanium can thermally stabilize the WO3, influencin
g also its electric properties. (C) 2001 Elsevier Science B.V. All rights r
eserved.