Ceramic pellets were prepared by mixing and heating Ca2P2O7 powder with various vol% of Na4P2O7 powder, and the transport properties were determined as a function of temperature by using complex impedance spectroscopy. It was shown that samples with 90 or 95vol% of Na4P2O7 exhibited a greatly enhanced conductivity.

V.Vincent, G.Nihoul, J.R.Gavarri: Solid State Ionics, 1996, 92[1-2], 11-24