Metallic High Reflective Coating is mainly practiced using Au,Ag,Al,Cr or Ni-Cr.This kind of coating is applied to the situation where a consistent high reflection on a wide spectrum range is needed.Their reflectance is lower than that of dielectric HR coating,but their spectrum can cover near-UV. Visible and near-IR. Dielectric coating is applied on the of metallic coating to prevent metallic coating from oxidization.