A thin diamond film bonded to a diamond substrate made by the process of heating a diamond substrate inside a vacuum chamber to about 500° C., cooling the diamond substrate, coating a first surface of the diamond substrate with chromium, depositing an initial layer of palladium, heating the diamond substrate, allowing the chromium and the diamond substrate to form a chemical bond, inter-diffusing the adhesion layer of chromium and the initial layer of palladium, cooling, depositing palladium, placing a shadow mask, degassing the vacuum, depositing a tin layer, assembling the tin layer, heating the tin layer, melting the tin layer, and bonding the thin diamond film to the diamond substrate. A thin diamond film bonded to a diamond substrate comprising a thin diamond film, a layer of chromium, palladium, tin, and a diamond substrate.