Figure 1 shows the relation between density ρ and molar volume Mv as a function of copper oxide. From this figure, can be observed that the ρ and Mv decreased with the increased of copper oxide content replacement the lead oxide. The decrease of density due to the molecular weight of CuO is lower than the molecular weight of Pb3O4. The decrease of the molar volume due to the decrease the number of oxygen and may be the ionic radius of copper ions less than the ionic radius of lead ions.
The density of all the glasses under study can be calculated from the following expression:
D = xLi2B4O7 d Li2B4O7+xPb3O4d Pb3O4+xCuOdCuO
where xLi2B4O7, xPb3O4 and xCuO are the molar fraction. And d Li2B4O7, dPb3O4 and dCuO are the values of theoretical density …show more content…
The oxygen packing density can be calculated from the relation [28–31] OPD = 1000*O/Vm where ‘O’ represents the numbers of oxygen in the oxide glass component. Oxygen packing density determines and drawn in figure 3. From figure 3, it can be observed that the values of Oxygen packing density decrease with the increase of Cu concentration. And the molar volume has the same behavior. The decrease of density and OPD values indicate the conversion of BO4 to BO3 that initiate the increase of number of bridging oxygen that make the glass more compact. …show more content…
However, Trg does not incorporate the other aspect of GFA,[39] which is the thermal stability of glass. The second parameter used to calculate the glass forming ability was ΔTx=Tx−Tg which expresses the width of the supercooled liquid region SCL, the temperature difference observed during heating between the onset crystallization temperature,
Tx and the glass transition temperature, Tg.
Usually, unstable glasses show a crystallization peak close to the glass transition temperature. Therefore, the temperature difference Tx−Tg between the two temperatures is a good indication of thermal stability because the higher the value of this difference, the more the delay in the nucleation process. Hence Trg and ΔTx each include only one aspect of GFA (either the ease of glass formation or the thermal stability of glass) and hence cannot measure GFA effectively.[40]
Other parameters used to calculate the glass forming ability such as γ, β, α and δ were therefore calculated and are tabulated in Table 2. These parameters are given by [41]
Trg =(Tg/Tl) (1) γ=TX/(Tl+Tg) (2) α=Tx/Tl (3) δ=Tx/(Tl−Tg) (4)
In addition a new parameter defined
The density of all the glasses under study can be calculated from the following expression:
D = xLi2B4O7 d Li2B4O7+xPb3O4d Pb3O4+xCuOdCuO
where xLi2B4O7, xPb3O4 and xCuO are the molar fraction. And d Li2B4O7, dPb3O4 and dCuO are the values of theoretical density …show more content…
The oxygen packing density can be calculated from the relation [28–31] OPD = 1000*O/Vm where ‘O’ represents the numbers of oxygen in the oxide glass component. Oxygen packing density determines and drawn in figure 3. From figure 3, it can be observed that the values of Oxygen packing density decrease with the increase of Cu concentration. And the molar volume has the same behavior. The decrease of density and OPD values indicate the conversion of BO4 to BO3 that initiate the increase of number of bridging oxygen that make the glass more compact. …show more content…
However, Trg does not incorporate the other aspect of GFA,[39] which is the thermal stability of glass. The second parameter used to calculate the glass forming ability was ΔTx=Tx−Tg which expresses the width of the supercooled liquid region SCL, the temperature difference observed during heating between the onset crystallization temperature,
Tx and the glass transition temperature, Tg.
Usually, unstable glasses show a crystallization peak close to the glass transition temperature. Therefore, the temperature difference Tx−Tg between the two temperatures is a good indication of thermal stability because the higher the value of this difference, the more the delay in the nucleation process. Hence Trg and ΔTx each include only one aspect of GFA (either the ease of glass formation or the thermal stability of glass) and hence cannot measure GFA effectively.[40]
Other parameters used to calculate the glass forming ability such as γ, β, α and δ were therefore calculated and are tabulated in Table 2. These parameters are given by [41]
Trg =(Tg/Tl) (1) γ=TX/(Tl+Tg) (2) α=Tx/Tl (3) δ=Tx/(Tl−Tg) (4)
In addition a new parameter defined