The aim of the study was to investigate the Mechanisms properties of thermal barrier coatings (TBCs) to enhance of performance evaluation characteristics and develop TBCs.Cobalt –base superalloy has been used as a substrate and zirconium stabilized Aluminum as ceramic topcoat , in addition the study include degradation behavior of system during thermal cycling (3hr per cycle in furnace) the failure of the aluminized was due to thermally grown oxide (TGO) interface. The fractures propagatethrough the interface and produce a deformation of the bond coating . the effect of cycle will result a spallation failure of the TBCsand this is also corresponding to a slightdegradation .The steam of salt (Nacl)and(Na2So4) mixture will affecton the coating lifetimes .The high temperature have a strong effect thermally grown oxide (TGO) which consistent with a first order growth of scale failer variation.

The working hard conducts that some material suffer from lead us to protect it from corrosion and give long life. When we select protective system we shall take three points, the work place, base structure and the protective system it self. In this study, we test two types of diffusion coated by cementation (Single Aluminized Coating, Thermal Barrier Coating) at (1000 0 C) with (2,4,6 h). The up take of aluminum and coating thickness obeys the parabola rule so that the coating process obeys diffusion process and the weight gain rate increase with the temperature increased. The other objective of this study was to see the degradation behavior of the systems during thermal cycling (three hour cycles in enhanced hotsalt solution). The single aluminized has good protects while the uncoated sample failed after five cycles. The thermal barrier coating has an excellent protection during the test time because of the good adhesion of Al 2 O 3 layer.

Solid state reaction method has been used to prepare samples with double partial substitution of Ag and Sr in Bi and Ba respectively, within the compound Bi 2-x Ag x Ba 2-y Sr y Ca 2 Cu 3 O 10+. The crystal structure has been studied by using X-Ray diffraction. The study has found that the prepared sample is tetragonal containing high percentage of Bi-2223 phases. As a result of partial substituting of Ag and Sr in Bi and Ba, it has been noticed that there is increasing in the grains size for super conducting as well as increasing in density which lead to the raising of the critical temperature and arrangement of crystal structure. Also the magnetic suscepitibility has been studied under normal atmosphere pressure and room temperature.

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