Ultra low thermal expansion phases: Substituted ‘PMN’ perovskites

Abstract

Abstract Among different principles which can be utilized in a structure to exhibit anomalously low thermal expansion, a ‘distributed’ phase transition is a candidate. Pb(Mg 1 3 Nb 2 3 ) 3 is a well known relaxor ferroelectric material in which such a transition occurs. The change in thermal expansion of PMN ceramics caused by partially substituting various ions at the B-site has been studied in order to see any new low expansion materials with good electrostriction properties exist. Partial ionic substitution of Ni 2+ , Co 2+ , Zn 2+ , Mn 2+ , Cd 2+ , Fe 3+ , Sc 3+ , Ti 4+ , Sn 4+ , Hf 4+ , Zr 4+ , and W 6+ was made at B-site. The sintering temperature was kept at 1250° for 1 hour. Thermal expansion data and their interpretations are presented.