Glass-forming region in the Ca–Si–O–N system using CaH2 as Ca source

Viscosity of high-nitrogen content Ca–Si–O–N glasses

“…2. The glass transition ranges conventionally associated to a η between 10 12 and 10 12.6 Pa s are in the 878-995 • C interval (Table 1) and are in excellent agreement with those previously determined by DTA 10,22 (Table 1). Moreover, both measurements show a linear increase of glass of 10 14 and 10 13 Pa s at 860 and 890 • C, respectively, for a Ca glass with 18 e/o N. In addition, the glass viscosity was found to increase with decreasing the size and increasing the field strength of the modifier ions.…”

“…SEM analysis leads to the same conclusions. 10 However, TEM analysis on N-rich La-Si-Al-O-N possibly indicates a phase separation in a length-scale of 5 to 10 nm in both La-Si-Al-O-N and La-Si-O-N glasses. But we cannot exclude an effect of sample thickness variation during measurement.…”

“…However, an alternative synthesis method developed by us has enabled the preparation of oxynitride glasses with significantly higher concentrations of nitrogen, as well as modifier additives, in various systems. [8][9][10][11] In the synthesis route, the modifier is introduced as a metal or metal hydride, which reacts with nitrogen gas at relatively low temperatures and forms reactive nitrides with no surface oxide layer. Theses glasses retain high amounts of the electropositive elements and nitrogen and exhibit very high values of glass transition temperatures, microhardness, elastic moduli and refractive index.…”

“…doi:10.1016/j.jeurceramsoc.2010.07.039 Table 1 Physical properties of the glasses -Vickers hardness (Hv) values were measured with a 500 g load 11 ; Young's and shear elastic moduli, E and G, were measured by means of ultrasonic echography 15 cerning synthesis and additional characterisations are given in Refs. 9,10 The amorphous nature of the glasses was verified by Xray powder diffraction, using a Guinier-Hägg camera and Cu K␣ 1 radiation. Cation concentrations were determined by energy dispersive X-ray point analysis and anion contents determined by combustion analysis (LECO equipment).…”

Compositional effects on the properties of high nitrogen content alkaline-earth silicon oxynitride glasses, AE=Mg, Ca, Sr, Ba

“…Videau et al 22 found that Mg and Ca oxynitride glasses, with the same amounts of N, have similar T g values, albeit slightly higher in the case of Mg, whereas the corresponding Ba glasses have lower T g values. However, contrary results were obtained by Drew et al, 23 14,[26][27][28][29] has enabled the preparation of oxynitride glasses with significantly higher concentrations of nitrogen, as well as modifier additives. In this synthesis route, the modifier is introduced as a metal or metal hydride, which reacts with nitrogen gas at relatively low temperatures and forms reactive nitrides with no surface oxide layer.…”