| Nuclear energy, which has clean, reaction safe and controlled, rich reserves of nuclear fuel, is one of the main ways to solve the present energy problem. However, it also faces the problem of nuclear waste disposal. The Accelerator Driven Sub-critical System(ADS) is regarded as a best way to handle nuclear wastes. However, the internal extreme environments of ADS system,which were long-term high temperature, high temperature gradient, intensive irradiation, and liquid metal induced severe corrosion, can cause a series of structural and mechanical property changes in materials, and these phenomena will seriously affect the safety and service life of the operating reactor. In consequence, the candidate structural materials to the ADS system possess high thermo-mechanical stability, low-activation properties, and excellent thermodynamic properties, especially resistance to irradiation performance were studied and choosed, which has important engineering significance.In this thesis, Al2O3-Ti O2 composite ceramic coating were obtained on the China Low Activation Martensitic(CLAM) steel by oxyacetylene flame spraying–laser in-suit reaction compound technology with Cr Fe, Fe Al and pure Ti powders. The surface of Al2O3-Ti O2 composite ceramic coatings are smooth, the microstructure of coatings are both homogeneous and dense, without defects such as crack free and pore etc. Meanwhile, a good metallurgical bonding is formed between the coating and the substrate. And the average micro-hardness of the coating reaches 0.21864.19 HV.The prepared Al2O3-Ti O2 composite ceramic coatings were irradiated with 200 ke V He ions at different doses. With the compute code SRIM 2013, the ion range from the surface of Al2O3-Ti O2 composite ceramic coating is 1.55μm. Furthermore, techniques such as Transmission electron microscopy(TEM), X-ray diffraction(XRD), Nano-indentation, friction and wear test apparatus, substrate stretching test, et al. were used to evaluate the irradiation effects of helium ions on the Al2O3-Ti O2 composite ceramic coatings.When the irradiation fluence was 5×1017ions/cm2, fully crystalline region, not fully crystalline region, amorphous region and obvious interface had been observed in the TEM images of the Al2O3-Ti O2 composite ceramic coating, and the crystal defects have a tendency to migrate and converge to the interface. Based on the XRD analyse, it is shown that the helium ions irradiation has no effect on the surface chemical composition and phase constitution of the Al2O3-Ti O2 composite ceramic coatings. While the surface mechanical properties for the coatings after irradiated by helium ions are different from that before irradiation, the nano indentation experiments show that the surface nano-hardness of the Al2O3-Ti O2 composite ceramic coating decreased with the increasing of helium ions irradiation fluence. Under the same load condition, with the changing of the helium ions irradiation dose, the mass loss of the coating increased, but the surface wear morphologies didn’t change obviously. The substrate stretching experimental result show that, when the surface quality of the tensile specimen was good, the helium ion irradiation has no remarkable effects on the interfacial bonding strength between the Al2O3-Ti O2 composite ceramic coating and the substrate. |
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