PREPARATION OF 2-LAYER COATINGS CONTAINING URANIUM OR THORIUM-DIOXIDEAND METALLIC NICKEL

Two-layer coatings MO2-Ni (M = U or Th) on quartz, Polikor, silicon, s teel, and copper are prepared by successive gas-phase pyrolysis of U(a cac)(4) or Th(acac)(4) and Ni(acim)(2) (acac = C5H7O2, acim = C5H7ONH) . The MO2 coatings (thickness up to 5 mu m) are formed in a reducing m edium at 500 degrees C; they contain up to 12 wt % carbon. Carbon-free ThO2 coatings having a good adhesion to quartz, Polikor, and silicon supports are formed in an oxidizing atmosphere at a rate of about 1.5 mu m h(-1). The photomicrographs of the surfaces of MO2 coatings (x 50 0) show that according to their morphology these coatings can be class ed with domal structures. According to X-ray diffraction analysis, sph erical MO2 globules are finely dispersed crystals, more ordered in the case of ThO2. The metallic nickel film, deposited in a reducing mediu m at 300 degrees C on the surface of MO2 coatings, repeats their relie f and at a thickness greater than 7 mu m can be continuous.