Composite Materials with Adjustable Thermal Expansion for Electronic Applications

In this paper, we discuss a newly characterized compound, ZrW 2 O g , that has been introduced into the composite materials with an adjustable and low thermal expansion for electronic applications. Offering a negative coefficient of thermal expansion (CTE) of approximate ‐9xlO –6 /°C in a large temperature range, ZrW 2 O g was used as a particle filler in polymer‐matrix composites. The paper presents two kinds of composites, that is, polyester and epoxy with various volume fractions of ZrW 2 0 g . The CTEs of the polyester/ZrW 2 O g and epoxy/ZrW 2 O g composites have been proven adjustable in the ranges of 94 to 56x10 –6 / °C and 54 to 18х 10 –6 /°C, respectively, with ZrW 2 O g filler from 0 to 30 vol%. In addition, the analysis about the interfaces between the matrices and filler indicated that the interfaces may be beneficial to reduce the overall thermal expansion of the composites. The methods to further decrease composite CTEs are also discussed.