Pressure-induced structural change of CaO–Al2O3–SiO2 melt: Insight from molecular dynamics simulation

Laser-Induced Structural Modification in Calcium Aluminosilicate Glasses Using Molecular Dynamic Simulations

“…The aforementioned densification process around silicon species, which primarily occurs from a reduction in inter-tetrahedral angle and little to no detectable change in the interatomic distance, is supported by our study. Previous studies 12,23 investigating compression of glass melts have found changes in the O-Al-O bond angle distribution are almost exclusively associated to Al (IV) . Based on these results, we have determined that 1) Si species are far less susceptible to laser-induced structural modifications compared to Al, 2) distortion to the O-Al-O bond angle are dependent on temperature and pressure generated from pulse energies, and 3) increased Al2O3/SiO2 ratio amplifies laser modified structural distortions.…”

“…Forming fivecoordinated Al and triclustered oxygen is necessary for charge compensation of NBO. Most NBO are associated with SiO4 units 12 . The Ca 2+ cation tends to be close to negatively charged species like [AlO4] -, [AlO5]and [NBO] -, therefore they are most likely to be found connecting [AlOx]units or along -Si-NBO units.…”

“…Due to the equal concentration of CaO and Al2O3, the system has no net charge. In theory, these glasses should be void of any NBO; however, Stebbins et al 38 have demonstrated, using 17 O NMR, the presence of NBO in otherwise charge neutral CAS glasses, also revealing most NBO occur at SiO4 sites 12 . Agnello et al 13 provide a detailed analysis of the Al (V) , in which all were Q 5 (meaning no NBO bonds were present) and 2-out-of-5 were TBO, while the other three bonds are bridging oxygens (BO).…”

“…Calcium aluminosilicate (CAS) glasses are well studied in materials research because of their superior mechanical-and physical-properties [12][13][14][15] . While prior works have investigated the structural dependence on composition and temperature [16][17][18][19][20] , studies of pressure induced structural changes primarily focus on peraluminous (R < 1) 20 and percalcic (R > 1) glasses 12,[19][20][21][22] .…”

“…Calcium aluminosilicate (CAS) glasses are well studied in materials research because of their superior mechanical-and physical-properties [12][13][14][15] . While prior works have investigated the structural dependence on composition and temperature [16][17][18][19][20] , studies of pressure induced structural changes primarily focus on peraluminous (R < 1) 20 and percalcic (R > 1) glasses 12,[19][20][21][22] . Limited work probing the silica-rich space along the tectosilicate join (R = CaO/Al2O3 = 1) has been reported [13][14][15]23 , and only a handful investigate pressure induced structural changes in the silica-rich CAS along the tectosilicate join [23][24][25] .…”