Crystallization in Lead Tungsten Fluorophosphate Glasses

• Autor(a) principal: Nardi,Rachel Prado Russo Delorenzo
• Data de Publicação: 2015
• Outros Autores: Braz,Celso Eduardo, Pereira,Camila, Freschi,Carolina Dakuzaku, Ferrari,Jefferson Luiz, Stucchi de Camargo,Andrea Simone, Eckert,Hellmut, Cassanjes,Fabia Castro, Poirier,Gael
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Materials research (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392015000100228
• topic: glasses; phosphate; lead fluoride

The glass forming ability was investigated in the codoped Er3+/Yb3+ ternary system NaPO3-WO3-PbF2 with increasing amounts of PbF2. It has been found that glass samples can be obtained for PbF2 contents ranging from 0 mole% to 50 mole% for the codoped samples and an undoped sample containing 60% of lead fluoride could also be vitrified. Thermal properties of the most PbF2 concentrated glasses exhibit strong dependence of the composition with a decrease of the glass transition temperatures and thermal stabilities against devitrification with increasing the lead fluoride content. These glass samples were heat-treated near the crystallization peaks and the X-ray diffraction measurements pointed out that the dominant phase which precipitates from the glass samples containing 40% and 50% of PbF2 is the lead fluorophosphate phase Pb5F(PO4)3 whereas the sample containing 60% of PbF2 exhibits a preferential bulk crystallization of cubic lead fluoride β-PbF2.