Zero Thermal Expansion in PbTiO₃-Based Perovskites

Abstract

Most materials expand on heating, known as positive thermal expansion. There are some instances most of which have been discovered in the past decade to exhibit a negative thermal expansion (NTE). [1][2][3][4][5][6][7][8][9] The nature of NTE behavior originates from the effect of atomic vibrations, (e.g., the low-energy transverse mode (ice), 2 the coupled rotation of rigid polyhedra (ZrW 2 O 8 , Fe[Co-(CN) 6 ]), 1,4 and active vibration modes of carbon fullerenes and nanotubes), 7 from the effect of magnetic transition (Invar alloy), 3 or from the changes in electron configuration (Sm 2.72 C 60 , YbCuAl). 8 The occurrence of NTE materials immediately found their important technical applications in many fields, because the overall thermal expansion coefficient (TEC) could be tailored by introduction of NTE materials. 1,2 In particular, zero thermal expansion (ZTE) is very interesting, where the volume neither expands nor contracts with the temperature fluctuation. 3-6 The ZTE could be achieved to form composite by combining the materials with positive thermal expansion with NTE materials. However, the fabrication of ZTE composite is hampered by the poor thermal stability of NTE compounds. For example, ZrW 2 O 8 will be decomposed at a relatively low temperature (777°C). 1 The requirement of ZTE will be satisfied if the ZTE is available in a single phase. Up to now, rare materials exhibit the novel ZTE, such as Invar alloys and Fe-[Co(CN) 6 ]. 3,4 Moreover, the ZTE generally appears in a low temperature (below room temperature). The ZTE over a wider temperature range would be very useful for the applications.PbTiO 3 (PT) as an important perovskite-type multifunctional material exhibits a unique NTE in the perovskite family. 9,10 The unit cell volume of PT contracts over a wide temperature range in the ferroelectric phase (25-490°C) with an average intrinsic volumetric TEC (-1.99 × 10 -5°C-1 ). 9b The NTE of PT-based compounds can be controlled over a large range from -0.11 × 10 -5 to -3.92 × 10 -5°C-1 , which covers the range found in almost all other known NTE oxides. 9 However, a low or ZTE could only be achieved by sacrificing the temperature range, that is, reducing the Curie point (T C ), such as for Pb 0.80 La 0.20 TiO 3 (-0.11 × 10 -5°C -1 , 25-130°C). 9b It is a challenge to expand ZTE to the hightemperature range. On the basis of our previously studied PbTiO 3 -based compounds, we could only access a low expansion or ZTE by reducing the tetragonality (c/a), resulting in the decrease in the ZTE temperature range (region II in Figure 1). To obtain the ZTE in a wider temperature range, a kind of PbTiO 3 -based compound should be found in the region I where c/a is large and the absolute value of TEC is low (Figure 1). Recently, in the PbTiO 3 -BiMeO 3 (Me is cations with an average valence +3), the Bi substitution plays an unusual role in which both T C and c/a are considerably enhanced, owing to the strong coupling between the Pb/Bi cations and the B-site cations with strong ferroelectricity activity, suc...

Temperature dependence of piezoelectric properties of high-TC Bi(Mg1/2Ti1/2)O3–PbTiO3

“…[1][2][3] The operating temperature of piezoelectric ceramics is generally limited to one-half of the Curie point ͑T C ͒ due to loss of polarization, typically at temperatures lower than 200°C ͓e.g., 150°C for the conventional piezoelectric materials based on the Pb͑Zr 1−x Ti x ͒O 3 ͑PZT͔͒ with a Curie temperature, T C = 386°C. 4 After excellent piezoelectric properties for ͑1 − x͒BiScO 3 -xPbTiO 3 ͑BS-PT͒ near the morphotropic phase boundary ͑MPB͒ ͑x = 0.64͒ were reported ͑piezoelectric coefficient, d 33 = 460 pC/ N, planar coupling coefficient, k p = 0.56, and T C = 450°C͒ recently, 5,6 the discovery of several promising high temperature piezoelectric materials with high performance followed in the general BiMeO 3 -PbTiO 3 system, [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] where Me can be a single cation of valency +3 ͑e.g., Sc 3+ and Fe 3+ ͒ or a mixture of cations with an average valence of +3 ͑e.g., Mg 1/2 Ti 1/2 and Ni 2/3 Nb 1/3 ͒. It has been proposed that the Bi substitution plays an unusual role of considerable enhancement of both Curie temperature ͑T C ͒ and tetragonality ͑c / a͒, which results from a strong coupling between Pb/Bi cations and B-site cations of strong ferroelectric activity, such as Ti, Zn, and Fe.…”

“…Hence, most recent studies have been focusing on nonscandium perovskites. [12][13][14][15][16][17][18][19][20][21][22][23][24] In fact, possible new compositions in BiMeO 3 -PbTiO 3 -based systems are plenty, because B-site Me of BiMeO 3 could be any combination, which gives an average valence of +3. According to the currently available literature, however, the design of BiMeO 3 -PbTiO 3 piezoelectrics faces a significant challenge in that only few systems form a MPB with PbTiO 3 .…”

“…This has been demonstrated in such systems as Bi͑Zn 1/2 Ti 1/2 ͒O 3 -PbTiO 3 ͑BZT-PT͒ and Bi͑Zn 2/3 Nb 1/3 ͒O 3 -PbTiO 3 . 7,[20][21][22][23][24] Table I lists the piezoelectric and related properties of BiMeO 3 -PbTiO 3 piezoceramics available in literature. It should be noted that most BiMeO 3 -PbTiO 3 compositions have a relatively high T C .…”

Low-temperature abnormal thermal expansion property of Mn doped cubic NaZn13-type La(Fe, Al)13 compounds

“…Therefore the abnormal thermal expansion (ATE) property including zero thermal expansion (ZTE) and negative thermal expansion (NTE) has become an advanced research focus especially in high-precision devices. In recent years, several kinds of materials with ATE property have been discovered, such as LiAlSiO4 (β-eucryptite), ZrW2O8, [3] ScF3, [4,5] PbTio3-based compounds, [6] La(Fe, Si)13-based compounds [7][8][9][10] and some antiperovskite manganese nitrides [2,11] . It is noteworthy that most of ATE materials are tuned to adjust the temperature range of ATE moving towards higher temperature span.…”

Residual tensile stresses and piezoelectric properties in BiFeO3-Bi(Zn1/2Ti1/2)O3-PbTiO3 ternary solid solution perovskite ceramics

“…Recently, it is demonstrated that adding Bi(Zn 1/2 Ti 1/2 )O 3 (BZT) into BF-PT to form ternary solid solution paves the road to obtain both mechanical and insulating robust ceramics for surveying their piezoelectric properties, which takes the following advantages: 1) negative TEC decreases to reduce tensile stresses caused by ferroelectric structural phase transition after sintering; [13][14][15] 2) thermodynamic stability of BiFeO 3 perovskite phase is enhanced to reduce the volatility of Bi 2 O 3 and resulted vacancies in crystallographic lattice; [16][17][18][19] 3) composition range of structural phase boundary is extended widely and 4) ferroelectric T C increased further more than 630 o C. 18,19 In the BF-BZT-PT ternary system, T C was observed around 700 o C for coarse-grained (0.85-y)BF-0.15BZT-yPT solid solution ceramics with 0.30 ≤ y ≤ 0.38 across the tetragonal-tetragonal/rhombohedral coexistent structural phase boundary, which can be modified furthermore through adjusting microstructural grain size and/or element substitution. [18][19][20] In contrast to Bi 4 Ti 3 O 12 system, perovskitestructured BF-BZT-PT ternary system takes advantage of the structural phase boundary like the PZT system intrinsically benefitting for high piezoelectricity 3,21,22 to design high performance ferroelectric piezoceramics suitable for high temperature applications through adjusting composition and crystallographic structure.…”