Topic: Flash sinter-crystallization – An innovative method to synthesize glass-ceramics

Lecturer: Prof. Ana Candida Martins Rodrigues, Department of Materials Science and Engineering, Federal University of São Carlos, Brazil

Time: December 4th, 2025, 14:30-15:30 UTC+8

Venue: Room 502, Xiuji Building, West Campus

Biography: Ana Candida M. Rodrigues is a Full Professor at the Department of Materials Science from Federal University of Sāo Carlos. She obtained her PhD from the former École Nationale Supérieure de Chimie de Grenoble (France). Her research focuses on glasses and glass-ceramics, with emphasis on electrical properties and ionic conduction. She dedicated several years researching the controlled crystallization of NASICON-type glass-ceramics and the microstructure-conductivity relationships. Now, she also applies flash-sintering, an innovative method for ceramic sintering assisted by an electrical field. She authored five pending and granted patents and more than 90 articles in international, referred journals, as well as six book chapters. Holder of two prizes in Brazilian conferences, she is affiliated with the Brazilian Ceramic Association (ABC) and the Brazilian Materials Research Society (SBPMAT). Currently, the Chair of the Technical Committee TC23 "Glass Education" of the International Commission of Glass, she is also the Coordinator of Education and Outreach of the Center for Research, Technology, and Education in Vitreous Materials (CeRTEV), an 11-year funded program by the Funding Agency from São Paulo State in Brazil, Fapesp. She will chair, in 2027, the Annual Meeting of the International Commission on Glass, to be held at Ilha Bela, Brazil, in September of that year.

Abstract: Flash sintering is a novel and rapidly advancing technique in materials science, particularly in ceramics and glass research. It involves applying an electric field to a material while it is being heated, significantly reducing the temperature required for sintering and accelerating the process. Here, we propose a new technique for the synthesis of glass-ceramics: the application of a newly developed method termed flash sinter-crystallization. In this method, a powder or a bulk piece of glass is subjected to a medium range electric field (~80-1000 V/cm). Thermal runaway, in which the heat generated by the Joule effect is greater than the heat released by the sample, leads to a rapid increase in temperature. In this way, crystallization occurs much faster and at a significantly lower furnace temperature than in the classical method. Also, energy consumption during flash-sinter crystallization is much lower than that required for a furnace heated by electrical resistance. In this talk, we will present some results on the flash-crystallization of a solid electrolyte with Nasicon structure Li1.5Al0.5Ge1.5(PO4)3 (LAGP) glass [1]. To obtain the glass-ceramics, we applied a “current ramp control.” Optimized conditions of the electrical field and electrical current lead to a polycrystalline solid electrolyte with higher ionic conductivity than glass-ceramics of the same composition obtained by classical crystallization. Also, the new technique was applied to a lithium disilicate dental glass-ceramic [2]. An original power ramp strategy allowed us to control the obtained crystallized phase as well as the color of the resulting material to be applied in dentistry.

References:

[1] J.V. Campos et al., Acta Materialia, 2023, 244, 118593.

[2] J.V. Campos et al., Acta Materialia, 2025, 284, 120620.

Rewritten by: Li Huihui

Edited by: Li Tiantian

Source: State Key Laboratory of Silicate Materials for Architectures