Relationship Between Structure And Performances Of Aluminosilicate Glasses And Melts

Aluminosilicate melts and glasses are important systems in geosciences due to their presence in the Earth’s magma and in glass science due to their widespread technological and industrial applications.For example,some compositions in the Na₂O-Al₂O₃-SiO₂ ternary phase diagram are good candidates for the storage of nuclear waste.Except that,the basis for new chemically strengthened cover glasses also forms the ternary phase diagram,such as Corning Gorilla electronic signs Glass.Hence,studying on the structure and properties of aluminosilicate glasses melts is great importance in to metallurgy,material science and geology.However,the structure origin of the properities for aluminosilicate glasses still a chanllege.In addition,glass poor mechanical properties limit the application range.What is the structure origin of the high hardness and crack resistance of aluminosilicate glass?How to design high performance glass through the recently proposed topology constraint theory?Based on the above questions,in this work we mainly through exploring the origin of the mixed modify effect,the structure evolution of aluminosilicate glass.According to the topology theory explain the aluminosilicate and design high performance glasses.The main innovation points and results are shown as follows:（1）We investigate the mixed alkaline earth effect in a float silicate glass series with varying the molar ratio of[MgO]/（[Ca O]+[MgO]）.In contrast to the shift of peak position at～1100 cm^-1 indicating the role of the aluminum speciation affecting the vibration modes for high and poor aluminosilicate glasses.By fitting the Vogel–Fulcher–Tamann equation to the high temperature viscosity data,we found a near-linear increase of the fractional free volume with the gradual substitution of Ca by Mg,confirming the dynamic structural mismatch model describing the mixed modifier effect.This work gives insight into the mixed modifier effect in glassy systems.（2）We focus on the mixed intermediate effect by partial substitution of Mg for Zn in sodium silicate glasses.The compositional dependences of microhardness and isokom temperature show a positive deviation from the linear tendency of end-members,different from the previous studies on the mixed alkaline earth effect.We suggest that,this is due to cationic potential energy mismatch decrease the network connectivity compete with the Zn and Mg increase the network connectivity by Raman.Finally,we discuss the mixed intermediate effect by dynamic and thermodynamic,which indicates that the Zn and Mg having a similar dynamic role in lower temperature but the dynamic role of Zn and Mg appears to be somewhat different as temperature increasing in silicate melts.（3）Mainly due to heterogeneous nucleation occurred at the melt-container interface,it is difficult to access the dynamics of supercooled liquids when using a conventional melting technique.To overcome this difficulty,here we apply a containerless aerodynamic levitation furnace by ourselves.In this work,we first measured the mixed alkaline earth effect on the thermophysical by the aerodynamic levitation furnace.In addition,we quench these melts to glass state,and then explore the mixed alkaline earth effects on Vickers micro-hardness and glass transition temperatures of the derived glasses.Based on the difference in the mixed alkaline earth effects between the studied silicate and aluminate glasses,we infer that alkaline earth ions acts as network modifiers in the former ones and as charge balancers to counter-act the negatively charged network in the latter ones.At last,we desin a high crack resistant glass through the topology consitran theory which the structure origin may come from the coordiction number chang of alumina.