Low-temperature sintering of Pb(Zr,Ti)O3 ceramics with BiFeo3 and Ba(Cu(0.5)W(0.5))O3 of perovskite-type crystal structure

Abstract

A simultaneous addition of perovskite-type BiFeO3 (BF) and Ba(Cu(0.5)W(0.5))O3 (BCW) has been effective for the low-temperature sintering of 0.5 wt percent MnO2-added Pb(Zr(0.53)Ti(0.47))O3 ceramics (PZT). The sintering of the optimum composition, 0.92PZT-0.O5BF-0.03BCW ceramics (PZT-C), was sufficiently performed at 935 C for 50 min through a conventional ceramic processing. Further addition of 0.08 wt percent CuO to PZT-C ceramics (PZT-C') gave the following characteristics: kappa(sub p) = 47.0 percent, Q(sub m) = 950, d(sub 33) = 236 x 10(exp -12) C/N, epsilon(sub 33)(sup T)/epsilon(sub 0) = 850, tan delta = 1.0 percent, T(sub c) = 290 C, and bulk density = 7.66 g/cu cm. The coexistence region of tetragonal and rhombohedral phases on the Morphotropic Phase Boundary (MPB) of PZT-C' was narrowed and shifted to the Ti-rich side of the composition, Zr/Ti = 52/48, by these two complex-oxides addition. The kappa(sub p) varied increasingly from 47.0 percent to 50.2 percent with this MPB shift. The shrinkage study of PZT-C' made clear that the above densification process was separated into the following three stages; the rearrangement of grains, the solution-precipitation or the grain boundary diffusion, and the grain growth. Also, the shrinkage and microstructural evolution of PZT-C' compacted body during heating could be facilitated by the occurrence of a transient liquid phase at the grain boundary predominantly composed of lead and copper oxides.

ペロブスカイト型BiFeO3(BF)およびBa(Cu(0.5)W(0.5))O3(BCW)の同時添加は、0.5重量%のMnO2を添加したPb(Zr(0.53)Ti(0.47))O3セラミック(PZT-C)の低温焼結に有効であった。最適組成である0.92PZT-0.05BF-0.03BCWセラミック(PZT-C)の焼結を、通常のセラミックス加工し、935度Cにおいて50分で十分に行えた。さらに、0.08重量%のCuOをPZT-Cセラミックに添加してたもの(PZT-C)で、次の特性を得た。すなわち、Kp=47.0%、Qm=950、d33=236×10{-12}C/N、ε33(T)/ε0=850、tanδ=1.0%、Tc=290度C、および容積重=7.66g/立法センチメートル。PZT-C'の類型相境界(MPB)上の正方晶系および三方晶系相の共存領域は、これら2つの複合酸化物の添加により、狭まり、かつTiが多い組成であるZr/Ti=52/48側にシフトした。このMPBシフトにともない、Kp値は47.0%から50.2%に増加した。PZT-C'の収縮の研究によって、上記のち密化加工は次の3段階に分離された。すなわち、粒子の再配列、溶液晶析または粒子境界拡散 および粒子成長である。また、加熱中のPZT-C'ち密体の収縮と微視構造の成長は、鉛と酸化銅がほとんどである結晶粒界での一時的な液相の生成により容易にすることができた。