The Effect Of Grain Size On The Rate Of Cerium Hydrogenation

The interaction of metal and hydrogen has been widely concerned by researchers,and it is also an important issue in engineering application.As an active metal,and because of the similarity between its relative position in 4f electronic system and that of Plutonium in 5f electronic system,Cerium was usually used as a simulation material of Plutonium.The study of cerium hydride corrosion behavior can provide empirical support for the study of plutonium hydride corrosion behavior.Changing grainsize is often used to control the strength and plasticity of metal.Accordingly,it is necessary to think about the influence of grainsize on hydride corrosion behavior.In this paper,grainsize growth kinetics of Ce on annealing process and hydriding behavior of Ce samples with different grainsizes was compared.The following rules were found.(1)Grain growth kinetics of Ce in annealing process.Grain growth index of Ce is 3 and activation energy is 0.27 eV during annealing process.The relationship between grainsize of Ce and annealing temperature and annealing time meet the formula D3-D3?6.81×105·(-0.27(eV)/RT)·t The relationship between microhardness and grainsize of Ce accord with formula HV=-21.17+287.26D-0.5(2)Hydriding experiments of on Ce with different grainsize show that hydride growth velocity increase and activation energy decrease with the grain size decrease.The relationship between activation energy of Ce samples with 200 ?m,125?m,and 100 ?m grainsize and temperature were k200?m=1.74×102 exp(-0.21(eV)/RT),k125?m?1.11×102 exp(-019(eV)/RT),and k100?m =9.6×101 exp(-0.18(eV)/RT)?(3)Hydriding experiments of on Ce with different grainsize show that activation energy of gas absorption decreases with the grain size decrease.The relationship between activation energy of Ce samples with 200 ?m,125 ?m,and 100 ?m grainsize and temperature were v200?m=2.38×102 exp(-0.18(eV)/RT),v125?m=6.4×101 exp(-0.15(eV)/RT),and v100?m=3.2×101 exp(-0.11(eV)/RT)(4)Products analysis.Products contain CeD2+x,CeD2,and Ce metal.