This invention relates to a
composite coating with low
thermal expansion coefficient and
low emissivity, its preparation method, and its application, belonging to the field of functional
coating materials technology. The
composite coating of this invention sequentially comprises a Si binder layer, a Ta₂O₅ stress buffer layer, and a Pt
metal layer. The Si binder layer serves as the binder layer, the Ta₂O₅ stress buffer layer as the low
thermal expansion stress buffer layer, and the Pt
metal layer as the
low emissivity functional layer. The
thermal expansion coefficient of Si is 3~4×10⁻⁶. ‑6 / ℃, while the coefficient of thermal expansion of Ta2O5 material is 6~7×10. ‑6 At ℃, the coefficient of thermal expansion of Pt material is 8~9×10⁻⁶. ‑6 / ℃, through gradient
coating design, the Pt
metal layer can have excellent thermal
cycling life and maintain
low emissivity performance, which is suitable for substrates with low thermal expansion coefficient, and meets the future requirements of lightweight hot-end components and
infrared signal shielding.