Inventors

Koshi TAKENAKA and Hidenori TAKAGI (Magnetic Materials Laboratory)

Background

Some materials, although rare, contract when heated under constant pressure.
Negative Thermal Expansion (NTE)

NTE Materials are active in many fields of industry.
Indispensable for control of thermal expansion
ex) Thermal expansion of Iron (10cm, 1°C) ： 1.2μm Line width of ULSI：32nm

Summary

Thermal expansion compensator

• Negative α is tunable across a wide range of values
• Giant NTE over α = -30ppm/°C
• Isotropic and Nonhysteretic (Cracking and distortions are avoided. We can use them in any form: ceramics, powders, etc)
• Antiferromagnetic (practical under magnetic field)
• Metallic (High electrical and thermal conductivity) &Hard (Mechanically though)
• Economical and Ecological (Mn, Zn, Cu, Sn, etc)

Merits

Thermal expansion adjustable composites

• Reliable, tough, and thermal expansion adjustable structural materials
• Extremely low thermal expansion plastics

References

• 1.Japanese Patent No.5099478, Japanese Patent No.5553366, US Patent No.7632480 etc.
• 2.Japanese Patent No.5935258
• 3.K. Takenaka and H. Takagi, Appl. Phys. Lett. 87 (2005) 261902.