Investigation Of Superheating Kinetics Of Nanoparticle Pb Embedded In Al Matrix

Melting is a very common phenomenon in the nature as well as an important field in the material research. Although many attempts have been made, the whole agreement on the mechanism of melting is far from reaching.The superheating phenomenon occurring in nanoparticles embedded in the certain matrix help people enter a new stage to delve themselves in the research of melting. Having a certain epitaxy relationship between the nanoparticles and matrix, which makes them be free from surfaces, a system such as Pb embedded in Al matrix has become a new model for studying the mechanism of melting.The Pb/Al ribbon, where the Pb nanoparticle embedded in Al matrix, was prepared by means of melt-spinning technology. Much work have been done to investigate melting process of the Pb nanoparticle embedded in Al at different heating rates by accurate calorimetric measurements. DSC curves show that part of Pb exhibits the phenomenon of superheating. Then, using Class Nucleation Theory, the equations for study the melting and superheating, were developed, which give reasonable explanation for characteristics of onset temperatures, peak temperatures and end temperatures obtained from DSC curves. By fitting the peak temperatures at different heating rates and their corresponding heating rates, the contact angle value 0 = 22.16" -22.93" and nucleation site number Mc =1.47xl(T8 - 2.26 xl0-8 were calculated. Compared with the contact anglevalue and nucleation site number obtained by Prof. Cantor, our values are very familiar to his results, which suggests that the mechanism of superheating of nanoparticle Pb embedded in Al matrix is a process of heterogeneous nucleation.