Study On Radition Damage Of Silicon Carbide And Some Metal Oxides

SiC and metal oxides of MgO, Al₂O₃, MgAl₂O₄ have been widely used in manyareas due to their outstanding physical property such as the superior high-temperatrueproperties, very high hardness and thermo-chemical stability. In these years a lot ofresearches on these materials have shifted to their behavior under energic particleirradiation, because they have been regarded as promising candidate materials formany important nuclear applications. As for SiC, besides its applications in energysystem, it is also been expect to use it as a new material for advanced electronicdevice which could work under irradiation environment. In this work, we concernabout the possible radiation damage in these materials, investigate the transformationmechanism of their structure and performance under irradiation and subsequentlythermal annealing.Ar ion implantation was first performed in these materials. Through analysis ofXRD and optical absorption spectra, we found that bombardment of energic ionseriously destroied crystal lattice, weaken the XRD peak which reflect latticecompleteness, but no typical defects was created after irradiation, for there are not anydetecable obsorption peak in the absorption spectra, even irradiated by a higher dose.Neutron irraidiation produced color centers in the several oxide crystals. As forMgO, irradiation generated large amount of optically detectable defects such as anionvacancies (primarily the one-electron F+ center), anion divacancies (F2) and somehigher order defects. Through ischronal annealing, these defects start a complexprocess of diminishing and transforming, and finally deplete all while annealing at900℃. It seems that the absorption band of 573nm and the band of 424, 451nm areresulted from different types of high order aggregate centers.Through the measurement of SiC neutron irradiated sample by XRD, we foundthat the thermal swelling coefficient of sample decreased after irradiation, and thedamage of the crystal lattice due to irradiation recover linearly with the increasingannealing temperature.