Structure and rheological properties of the RE–Si–Mg–O–N (RE=Sc, Y, La, Nd, Sm, Gd, Yb and Lu) glasses

First principles molecular dynamics of silicate oxynitride melt doped with scandium, yttrium and lanthanum

“…Percentages of Q n units in the lanthanum system together with SiO 3 N, SiO 2 N 2 , and SiON 3 units, which can be also found in oxynitrides, are summarized in Table 4. The table is completed with 29 Si MAS-NMR data published by Lofaj et al [5].…”

“…The electronic structure of the systems is treated by means of the density functional theory (DFT) [10] with a plane-wave basis set for the electronic wave-functions, and pseudopotentials for the core states. This work follows the extensive experimental research carried out by Lofaj and co-workers [5,6,11]. Deeper analyzes of pair RDFs and atomic local structures of the simulated systems were published in Ref.…”

“…However, these glassy layers of the nanometer order are very difficult to be studied experimentally [2][3][4]. Therefore, the structure and properties of such layers are mostly extrapolated from bulk oxynitride glasses [5][6][7]13,14]. Atomistic computer simulations are, in principle, able to model both thin IGF [8] and bulk structures [9].…”

“…Here, we focus on Q n units and silicon tetrahedra with some amount of nitrogen anions. Such units were identified by 29 Si MAS-NMR [5]. …”

Viscosity and surface tension measurements of RE₂O₃–MgO–SiO₂ (RE=Y, Gd, Nd and La) melts

“…Again, as mentioned above, Y 2 O 3 has weaker effect on increasing the surface tension. Lofaj et al have investigated the structure and physical properties (hardness, 24) glass transition temperature 41) and density 42) ) of Me-Mg-Si-O-N (MeϭSc, Lu, Yb, Y, Sm and La) oxynitride glasses and reported that these properties varied linearly with radius of the Me 3ϩ cation, moreover depending on whether Me 3ϩ belong to the 3rd group (Sc and Y) of the periodic table of elements or to the lanthanides, there were two distinct correlations. They have estimated that the deviations of physical properties from linearity were basically attributed to the considerable difference of atomic weight between lanthanide and non-lanthanide elements.…”