The Investigation Of Glass-Foring Ability

The ability of substances to vitrify on cooling from the melt is known as glass-forming ability (GFA) and has been the object of theoretical and experimental investigate for several decades. The reason of glass transition is unknown.How to understand and quantify the glass forming ability is important to the glass industry and research. The main purpose of this article is to study the effect of oxide on the glass forming ability and silicate glass melt properties.The glass-forming ability for glasses are very promising materials for future structural that do not have a structure with long-range atomic order like crystalline materials do, but have pronounced short-and medium-range order. Glass formation is always a competing process between liquid phase and the resulting crystalline phases. If the liquid phase is stabilized upon cooling and the competing crystalline phases are difficult to precipitate out, then the glass formation of the melt would be facilitated. The compositional dependence of glass forming ability (GFA) of five samples of glass melts is studied by measuring the viscous behavior and crystallization tendency, the glass transition temperature Tg, crystallization temperature Tc, and the melting temperatures Tm has been investigated by a differential scanning calorimeter (DSC) they are considered to be related to the glass forming ability (GFA). So, it is necessary to study the dependence of Tg, Tc and Tm on the composition and also to search for correlations between the Zn2+/Mg2+ with the GFA. Measured the glass stability (GS) against devitrification on heating (evaluated the Hrubyy parameter KH=(Tc-Tg)/ (Tm-Tc), and the parameter Kw=(Tc-Tg)/Tm)and a criterion of glass-forming ability (GFA) with the changed of the Zn2+/Mg2+ ratio.At the time Cpl/Cpg. △Cp, △E(HT)、 (So)、fg and dCpg/dT has a connection with the glass forming ability. Knowledge of the relationship between temperature vs crystallization behavior.We report a detailed calorimetric study concerning the influence of Yb2O3and Er1O3 on the non-isothermal crystallization in phosphosilicate melts. A special type of surface crystallization of MgO-Al2O3-SiO2 system glass was recently observed.In this work, we found the viscosity as a function of temperature for glass melts were consist with the equation and the viscosity with the change of Zn2+/Mg2+ ratio have a maximum. The liquid fragility index m has been calculated which used MYE GA equation that had a guide for glass forming ability.It is interesting that the glass will have a surface crystallization if it is in the ambient conditions with air. The volume nucleation is promoted for MgO-Al2O3-SiO2 glasses if the ambient contain N2 vapor. At the time we used JMA equation calculate the crystallization.In this paper we review some pertinent research aimed at understanding the relationship of surface nucleation with the surface rough. We emphasized the kinetics of surface nucleation and consider the effects of surface quality, cracks and surrounding atmosphere on crystallization. The results show that Yb3+/Er3+ions promote the Zn2SiO4 crystal formation the glass phase separation and reduce glass-forming ability but suppress the Na3PO4 and AIPO4 formation during cooling.The non-isothermal melt-crystalliza tion kinetics can be well described by the Avrami model. The activation energy Ee of crystallization in both the undoped and Yb3+/Er3+codoped samples during cooling is determined using the differential iso-conversional method of Friedman. The value decreases with crystallinity during cooling for both glasses, and introducing Yb3+/Er3+ to an increase in energy barrier of crystallization upon cooling.