Properties of Gold coating
High infrared reflectivity: gold coating has very high reflectivity (up to 95%-99%) in the near-infrared (above 700nm) to far-infrared wavelengths (especially 1-20μm), but lower reflectivity in the visible region (yellowish).
Oxidation resistance: gold itself is chemically stable and corrosion-resistant, but the pure gold coating is softer and easier to scratch, requiring a protective layer to enhance durability.

What are the applications of protective gold mirrors?
Infrared optical systems: laser processing (e.g. CO₂ lasers), thermal imaging, infrared sensors.
Aerospace: infrared reflectors for satellites, space telescopes, utilizing the stability of gold coating in the space environment.
Scientific research instruments: spectrometers, infrared microscopes and other equipment requiring high reflectivity.
Industrial and medical: high temperature measurement, medical laser equipment.