Two kinds of Ti-rich TiNi shape memory thin films were deposited onto monocrystal silicon substrates at room temperature and high temperature by using the magnetron-sputtering technique. Their crystallizing procedures are different from each other. The first type of film was originally amorphous and post-crystallized at a higher annealing temperature (600 • C) after sputtering, but the second film type was crystallized in situ during sputtering at about 500 • C. It was found that there are clear differences of microstructure and characteristics between both kinds of film, such as grain size, growth texture, stress range, phase transformation behaviors etc. In order to improve and enhance film properties, the objective of the present work is to reveal the reason for these differences occurring and understand the relationship between the crystallizing procedures, microstructures and characteristics of the films.

The effects of poling state and pores on the fracture toughness of Pb(Zr 0?95 Ti 0?05 )O 3 (PZT 95/5) ferroelectric ceramics were investigated. X-ray diffraction analysis and piezoelectric constant measurements reveal that the phase structures of PZT 95/5 ceramics change with the poling state, which significantly affects the fracture toughness. The poled PZT 95/5 ceramics demonstrate higher fracture toughness than the unpoled ceramics, and their fracture toughness significantly increases after the pressure depoling. As the porosity of ceramics increases with addition of poreformer during preparation, their fracture toughnesses all decrease accordingly either in poled state or unpoled state. The effect of pore size on the fracture toughness is subtle for the poled ceramics, but for the hydrostatic pressure depoled porous PZT 95/5 ceramics, their fracture toughness increases with the increase in pore size. A new stress model is proposed to explain the pore size effect on the fracture toughness of hydrostatic pressure depoled PZT 95/5 ceramics.

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