THE ADDITIONAL PROPERTIES IN DEFECT CONTROLLED CERAMICS

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The ceramics(AIN,BN)possess a various interesting characterestics, such as,high melting point,very high thermal conductivity and extreme hardness.It is one of the primary candidate materials for use in fusion reactor and conversion of energy at elevated temperature environments. It is the purpose of this experiment to investigate the relation between the defect production and the change of mechanical properties in the nitrides.The production point defects induced by reactor(KUR) neutron and the thermal behavior of the defect in sintered AIN and c-BN were studied using optical a sorption and ESR methods.Further,the enhancement of hardness in irradiated nitrides were also estimated.1.The specimens were irradiated by neutrons in the range of 2.8 x 10^<15> - 5.3 x 10^<16>n/cm^2(fast neutron:E>0.1 MeV) at 25 K.Fast neutron bombardment and the unclear reactions ^<10>B and ^<14>N with released high energy produce the various type of defects in the nitrides. The defect corresponding the ESR signal in assigned to be an electron trapped nitrogen vacancy. 2.Hardening after neutron irradiation was also studied in these nitrides using the identation method. In especially,hardness in c-BN increased clearly with neutron dose.