Near-zero thermal expansion of ZrW₂O₈/Al–Si composites with three dimensional interpenetrating network structure

Negative thermal expansion (NTE) materials can compensate high thermal expansion of metal materials, showing great potential use in precision instruments and microelectronics field. We developed a near-zero thermal expansion ZrW₂O₈/Al–Si composites with three dimensional mutually interpenetrated structure. Pressure infiltration ensured dense structure and mild interface reaction. The resulting composite has ultra-low thermal expansion (1.09 × 10⁻⁶ K⁻¹) in a broad temperature range of −50 to 120 °C (ΔT = 170 °C). The content of high pressure phase (γ-ZrW₂O₈) drops dramatically from 71.4% for the particle reinforced composite to 18.7% for the interpenetrating composite. Raman tests and numerical computational results indicated that the residual stress can be effectively released in the interpenetrating composites. This low dense and ultralow thermal expansion results in ideal materials for precision instruments and microelectronics component such as optical communication and gyroscope.