Theoretical and Experimental Parameters of the Structure and Crystallization Kinetics of Melt-Quenched As30Te64Ga6 Glassy Alloy

Abstract

The present framework reports the structural, fundamental parameters, and crystallization kinetics of the melt-quenched As30Te64Ga6 chalcogenide glass. The energy dispersive Xray analysis of the As30Te64Ga6 glassy system reveals that the constituent element ratio of the investigated bulk sample agrees with the nominal composition. Also, X-ray diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to characterize crystallization kinetics, and structural properties; respectively. Four characteristic temperatures related to various phenomena are observed in the investigated DSC traces. The first one is that corresponds to the glass transition temperature. The second one is ( 1 , and 2 ) that corresponds to the onset of the double crystallization temperatures. The third one ( 1 , and 2 ) identifies the double peak crystallization temperatures. The last characteristic temperature ( ) is the melting point.The XRD analysis indicates the amorphous structure of the as-prepared glassy alloy, while the annealed samples are polycrystalline. The crystallization kinetics of the As30Te64Ga6 bulk are studied under non-isothermal conditions. In addition, the values of various kinetic parameters such as the glass transition activation energy, weight stability standard, and Avrami support were determined. The activation energy of the crystallization process for As30Te64Ga6 glass alloy was calculated using classical methods. The results indicated that the rate of crystallization is related to thermal stability and the ability to form glass. Kinetic parameters have been estimated with some conventional methods and found to be dependent on heating rates (β).

Activation energies during glass transition and fragility of the As30Te64Ga6 chalcogenide glass

“…Figure 1(a) presents DSC thermograms of As 30 Te 64 Ga 6 glasses at different heating rates from 310 K, far below the glass transition temperature up to 670 K which is well above the melting point. One can distinguish starting from lower temperature, first the glass transition with an endothermal enthalpy peak in the range 390-420 K. A first exothermic crystallization peak in the range 440-460 K corresponds to the appearance of binary crystalline phases attributed to the hexagonal phases of As 2 Te 3 and Ga 7 Te 10 as proven by XRD [18], and the second exothermic peak in the range 550-575 K corresponds to the appearance of other binary phases of the monoclinic GaTe and the hexagonal phase of Ga 2 Te 5 [18]. The melting of all crystalline phases is in the range 635-650 K. The detailed study of the crystalline phases occurring while heating or annealing on the same samples could be found elsewhere [18,19].…”

“…A fast quenching in an ice-water mixture to avoid the crystallization was the final step of sample preparation. The amorphous nature of the sample was checked by X-rays' diffraction (XRD) [18]. The concordance of the preparation composition and the real sample composition was also checked by EDX [18].…”

“…The amorphous nature of the sample was checked by X-rays' diffraction (XRD) [18]. The concordance of the preparation composition and the real sample composition was also checked by EDX [18]. Effects of annealing on the structure and the optical properties on the prepared sample could be found also elsewhere [19].…”

“…In order to make the glassy state more stable, tune the band gap and enhance different physical properties, often ternary and quaternary compounds based on the addition of suitable elements are studied [7,[11][12][13][14][15][16]. Effects of addition of Ga on different optical, electrical and crystallization properties of the binary compound (As x Te 100-x ) were investigated [14,[17][18][19]. However, the study of the glass transition features such as the activation energy and fragility were not well addressed for such ternary compound despite its importance for the glassy state stability.…”

“…Differential scaning calorimetry (DSC) was shown to be an efficient experimental technique for the investigation of different thermally activated processes in glasses [18,[20][21][22][23]. In particular, since the seminal work of Kissinger [24] and Moynihan [25,26] using DSC for the investigation of kinetic and structural relaxation, iso-conversional methods became an established technique.…”