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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The diffusion coefficient controlling crystal growth in a silicate glass-former

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Author(s):
Cassar, Daniel Roberto [1] ; Rodrigues, Alisson Mendes [1] ; Ferreira Nascimento, Marcio Luis [2] ; Zanotto, Edgar Dutra [1]
Total Authors: 4
Affiliation:
[1] Univ Fed Sao Carlos, Dept Mat Engn, CeRTEV, Sao Carlos, SP - Brazil
[2] Univ Fed Bahia, Polytech Sch, Dept Chem Engn, Vitreous Mat Lab, Salvador, BA - Brazil
Total Affiliations: 2
Document type: Journal article
Source: INTERNATIONAL JOURNAL OF APPLIED GLASS SCIENCE; v. 9, n. 3, p. 373-382, JUL 2018.
Web of Science Citations: 4
Abstract

One of the most relevant open issues in glass science refers to our ignorance concerning the nature of the diffusing entities that control crystal nucleation and growth in non-crystalline materials. This information is very relevant because all the existing nucleation and growth equations account for the diffusion coefficient (D-U) of these unknown entities. In this article, we measured the shear viscosity () and the crystal growth rates of a supercooled diopside liquid (CaMgSi2O6) in a wide temperature range. The well-known decoupling of viscosity and crystal growth rates at deep supercoolings was detected. We tested and analyzed 4 different approaches to compute D-U, three existing and one proposed here. As expected, the classical approach (D-U similar to (-1)) and the fractional viscosity approach (D-U similar to (-epsilon)) were not able to describe the crystal growth rates near the glass transition temperature. However, our proposed expression to calculate D(U)gradually changing from a viscosity-controlled to an Arrhenian-controlled processwas able to describe the available data in the whole temperature range and yielded the lowest uncertainty for the adjustable parameters. Our results suggest that viscous flow ceases to control the crystal growth process below the so-called decoupling temperature, corroborating some previous studies. (AU)

FAPESP's process: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass
Grantee:Edgar Dutra Zanotto
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC
FAPESP's process: 11/18941-0 - Diffusion, crystallization, viscous flow and relaxation kinetics in diopside and lithium diborate glasses
Grantee:Daniel Roberto Cassar
Support type: Scholarships in Brazil - Doctorate (Direct)