The widely used piezoelectric Pb(Zr 1−x Ti x )O 3 ceramics have been known to have Zr 4+ and Ti 4+ randomly distributed on the B-site lattice in the ABO 3 perovskite structure. In this study, we attempted to develop long range 1:1 B-site cation order by forming the solid solution of (1 − x)Pb(Mg 1/2 W 1/2 )O 3 − xPb(Zr 0.5 Ti 0.5 )O 3 (x ≥ 0.60). High temperature X-ray diffraction tests indicate that the cation order is embedded in the structural order. The solid solution ceramics appear to have a non-cubic paraelectric phase above their Curie temperatures. The competition between the antiferroelectric order in Pb(Mg 1/2 W 1/2 )O 3 and the ferroelectric order in Pb(Zr 0.5 Ti 0.5 )O 3 leads to the relaxor ferroelectric behavior in the solid solution. Since the temperature at dielectric maximum, T m , is significantly above room temperature, regular polarization versus electric field hysteresis loops are recorded in these compositions at room temperature. In addition, these ceramics show very good piezoelectric properties.Abstract The widely used piezoelectric Pb(Zr1-xTix)O3 ceramics have been known to have Zr 4+ and Ti 4+ randomly distributed on the B-site lattice in the ABO3 perovskite structure. In the present work, we attempted to develop long range 1:1 B-site cation order by forming the solid solution of (1- . High temperature x-ray diffraction tests indicate that the cation order is embedded in the structural order. The solid solution ceramics appear to have a non-cubic paraelectric phase above their Curie temperatures. The competition between the antiferroelectric order in Pb(Mg1/2W1/2)O3 and the ferroelectric order in Pb(Zr0.5Ti0.5)O3 leads to the relaxor ferroelectric behavior in the solid solution. Since the temperature at dielectric maximum, Tm, is significantly above room temperature, regular polarization vs. electric field hysteresis loops are recorded in these compositions at room temperature. In addition, these ceramics show very good piezoelectric properties.
Polymer transfer films are thought to reduce friction and wear during sliding. In such cases, a continuous, uniform transfer film is thought to yield better wear performance. However, several polymers, including the thermoplastic polyetheretherketone (PEEK), do not always display this behavior. Recent works analyzing transfer film quality of PEEK resulted in no clear correlation to wear. Currently, the mechanisms for PEEK transfer film development are unknown, but there is evidence suggesting roughness orientation relative to sliding and frictional heating play key roles. In this work, the development of PEEK transfer film is explored in relation to multidirectional versus linear sliding, roughness orientation and temperature rise. Three distinct wear paths were chosen for wear tests. The transfer film of the square wear paths was analyzed using white light profilometry and imaging software to obtain the volume and area coverage by the film. The temperature rise during sliding of the bulk polymer pin was recorded with infrared camera radiometry for linear reciprocating tests. Scratch tests and chemical etching were conducted on the polymer pin surface to evaluate any directional bias or crystallinity orientation induced by sliding. It was found that wear debris and polymer chain orientation play no noticeable role in PEEK's transfer film formation. The transfer film gradient increased with frictional heating, and transfer film color changed under certain conditions. This color changed also correlated to reduced wear. This study also confirms that transfer film development is strongly dependent on roughness orientation, and its effects are examined.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.