Progress of Research in Negative Thermal Expansion Materials: Paradigm Shift in the Control of Thermal Expansion

Abstract

To meet strong demands for the control of thermal expansion necessary because of the advanced development of industrial technology, widely various giant negative thermal expansion (NTE) materials have been developed during the last decade. Discovery of large isotropic NTE in ZrW2O8 has greatly advanced research on NTE deriving from its characteristic crystal structure, which is now classified as conventional NTE. Materials classified in this category have increased rapidly. In addition to development of conventional NTE materials, remarkable progress has been made in phase-transition-type NTE materials using a phase transition accompanied by volume contraction upon heating. These giant NTE materials have brought a paradigm shift in the control of thermal expansion. This report classifies and reviews mechanisms and materials of NTE to suggest means of improving their functionality and of developing new materials. A subsequent summary presents some recent activities related to how these giant NTE materials are used as practical thermal expansion compensators, with some examples of composites containing these NTE materials.

Negative Thermal Expansion Near the Precipice of Structural Stability in Open Perovskites

“…This is an example of a route to achieving NTE which relies on broadened phase transitions between a low-temperature high-volume phase fluctuating into a high-temperature low-volume phase, other examples of which include the industrial alloy InVar (Guillaume, 1920) (Fe 64 Ni 36 ) and more recently discovered NTE materials (Takenaka and Takagi, 2005; Azuma et al, 2011; Qu et al, 2012; Chen et al, 2013a,b) (for more details on this approach, see Takenaka's review in this volume Takenaka, 2018). While this route to realizing NTE is promising for many applications requiring only dimensional concerns, NTE at these broadened transitions occurs only in heavily restricted regions of the magnetic and electronic phase diagrams, constraining a thermodynamic number of degrees of freedom to achieve a single mechanical characteristic.…”

Spray‐dry synthesis of β‐Cu1.8Zn0.2V2O7 ceramic fine particles showing giant negative thermal expansion

“…For many NTE materials without microstructural effects, thermal expansion of resin matrix composites is not exactly the ROM prediction. It is slightly below the ROM prediction because thermal expansion of the inorganic NTE materials with a larger elastic modulus is reflected more strongly via elastic interactions at the interface . In addition, for epoxy resin composites containing Ca 2 Ru 1‐ x Fe x O 4 and Ca 2 Ru 1‐ x Sn x O 4 , in which the microstructures produce the NTE, thermal expansion of the composites is slightly but definitely below the ROM estimate.…”

“…It is slightly below the ROM prediction 20,26-28 because thermal expansion of the inorganic NTE materials with a larger elastic modulus is reflected more strongly via elastic interactions at the interface. 1 18 in which the microstructures produce the NTE, thermal expansion of the composites is slightly but definitely below the ROM estimate. These results are regarded as evidence that the microstructure survives composite fabrication and that the NTE of the powder is close to that of bulk.…”

“…Rapid advances in modern technology have led to increasing demands for precise control of the dimensions and shapes of elements. To satisfy those demands, control of thermal expansion has emerged as an important issue in all industries . Recently, it has become necessary to control thermal expansion in local regions of specific components at the micrometer level, especially in the field of electronic devices .…”

“…To satisfy those demands, control of thermal expansion has emerged as an important issue in all industries. 1 Recently, it has become necessary to control thermal expansion in local regions of specific components at the micrometer level, especially in the field of electronic devices. 2 To meet this demand, micrometer or submicrometer scale fine particles are necessary for use as thermal expansion compensators.…”