Fabrication and ferroelectric properties of highly dense lead-free piezoelectric (K_(0.5)Na_(0.5))NbO_3 thick films by aerosol deposition

摘要

Lead-free piezoelectric thick films of (K_(0.5)Na_(0.5))NbO_3 were fabricated by aerosol-deposition method. The thickness of KNN film was 7.1 μm and fully dense films were obtained. The dielectric constants ε_3~T/ε_0 of the as-deposited and annealed films at 1 kHz were 116 and 545, respectively, which are higher than any previously reported values for lead-free piezoelectric thin/thick films, either without or with heat treatment. The ferroelectric properties were improved after annealing and the maximum values of P_r=8.1 μC/cm~3 and E_c = 100kV/cm were achieved. These values are markedly superior to those of sintered KNN ceramic counterparts.