Details

Autor(en) / Beteiligte

• Bocker, Christian
• Funke, Christian
• Rüssel, Christian

Titel

Strengthening of a zinc silicate glass by surface crystallization

Ist Teil von

• Materials letters, 2017-11, Vol.207, p.41-43

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Surface crystallization of a zinc silicate phase.•Thermal treatment leads to 85µm thick surface layer.•A mismatch of the CTE from the bulk/surface leads to compressive stresses.•A bending strength of 219MPa was reached; the glass shows a strength of 73MPa. Glasses with the composition 41ZnO·49SiO2·4La2O3·6Al2O3 were crystallized 100K above glass transition temperature. This resulted in the surface crystallization of an unknown phase chemically close to willemite. After 20h, a 85µm thick surface layer was formed which was composed of dendrite-like structures and an interpenetrating glass phase. The bulk glass has a coefficient of thermal expansion much larger than that of the surface layer. This leads to compressive stresses at the surface and a notable increase in the mechanical strength. After crystallization for 20h at 800°C, a four point bending strength of 219MPa was reached while the glass shows a strength of 73MPa. This may help to improve the mechanical properties of glasses and might also be important for ceramic glazes.