| Summary: | 博士 === 大同大學 === 材料工程學系(所) === 93 === A modified TRD (Thermoreactive Deposition / Diffusion) has been investigated in a low pressure fluidized bed furnace in this study. The steel specimens AISI D2 were positioned above the surface of the alloying powder. The activator was periodically introduced into the alloying powder to provide the working atmosphere for the required process. Since the pressure of the retort was maintained between 6.7×102 Pa and 5.3×104 Pa, the consumption of fluidized gas (argon) was reduced significantly. A modified TRD also significantly increased the working space of the treating zone. Furthermore, the kinetics of reaction K = K0 exp(-Q/RT) was empirically determined in this study. It is shown that the activator, NH4Cl, can effectively lower the activation energy Q, as well as enhance the formation rate of the carbide layer.
The chromium nitride obtained from TRD followed by plasma nitriding (dual treatment) provides more resistant than that of the solely TRD treated one.
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