Hot dip aluminised coatings with pure Al, Al-3Si and Al-7Si melts had been produced on 9Cr-1Mo steels and subsequently heat treated at 900uC for 5 h under oxidising conditions to generate alumina films over Fe-Al diffused case. The characterisation of these samples by X-ray diffraction and SEM-EDX techniques indicated reduction in the post-heat treated aluminide case depth with increasing Si concentration. Further, it was observed that after oxidation heat treatment, pure Al coated samples indicated c-Al 2 O 3 and h-Al 2 O 3 , while Al-7Si coated samples revealed transformation of metastable h-Al 2 O 3 phase to stable a-Al 2 O 3 phase. The present paper describes change in morphology of oxide after thermal oxidation from c to h and h to a as a function of the Si content of Al melt in hot dip aluminised 9Cr-1Mo steels. The effect of Si on the diffused aluminide case depth is also discussed.
Polymethyl methacrylate (PMMA) was prepared by solution polymerization method. Different concentrations (10, 20 and 40%) of Ni powder were dispersed in PMMA and the composite films were prepared by casting method. These films were irradiated with 120 MeV Ni 10+ ions at a fluence of 5 × 10 12 ions/cm 2 . Electrical, structural and chemical properties of the composites were studied by means of an LCR meter, X-ray diffraction, FTIR spectroscopy and SEM/AFM, respectively. The results showed that the conductivity increases with metal concentration and also with ion beam irradiation. This reveals that ion beam irradiation promotes the metal/polymer bonding and converts polymeric structure into hydrogen depleted carbon network. It was observed from XRD analysis that percentage crystallinity and crystalline size decrease upon irradiation. This might be attributed to rupture of some polymeric bonds, which is also corroborated with FTIR spectroscopic analysis. Ion beam tempts graphitization of polymeric material by emission of hydrogen and/or other volatile gases. Surface morphology of the pristine and irradiated films was studied by atomic force microscopy (AFM)/scanning electron microscopy (SEM). Result showed that the surface roughness increases after ion beam irradiation.
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