Hydrothermal synthesis of ZrW2O8 nanorods and its application in ZrW2O8/Cu composites with controllable thermal expansion coefficients

High purity ZrW2O8 powders with negative thermal expansion were hydrothermally synthesized in HCl solution. Unreacted ZrW2O8/Cu was fabricated by hot-pressing. Sn addition enhanced the densification of composite compact. Low hot-pressing pressure and relative loose microstructure of the composites can effectively prohibit the formation of high pressure γ-ZrW2O8. The thermal expansion curves were stable and uniform without anomalously large expansion. The coefficients of thermal expansion decreased with the ZrW2O8 volume fraction and a value of 1.6 × 10−6/°C was obtained for 68 vol.% ZrW2O8/Cu. Microstructural anisotropy led to obvious thermal expansion coefficient anisotropy.