Comparing hydrothermal sintering and cold sintering process: Mechanisms, microstructure, kinetics and chemistry

Arnaud Ndayishimiye (1, 2) , Mert Sengul (1, 2) , Sun Hwi Bang (1, 2) , Kosuke Tsuji (3, 2, 1) , Kenji Takashima (1, 4) , Thomas Hérisson de Beauvoir (5) , Dominique Denux (6) , Jean-Marc Thibaud (6) , Adri C.T. van Duin (1, 2, 7) , Catherine Elissalde (6) , Graziella Goglio (6) , Clive Randall (1, 2)

1 Materials Research Institute
2 Department of Materials Science and Engineering
3 Penn State - Pennsylvania State University
4 TAIYO YUDEN CO., LTD.
5 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
6 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
7 Department of Mechanical Engineering

This study reports the sintering of zinc oxide (ZnO) through the comparison between the hydrothermal sintering (HS) and the cold sintering process (CSP) operating in closed and open conditions, respectively. Sintering was performed at 155 ± 5 °C applying a pressure of 320 MPa, and during different holding times (0 min, 20 min, 40 min and 80 min). Whatever the low sintering process used, ceramics characteristics are almost similar in terms of relative densities and ZnO structure. However, several differences such as the nature of stabilized phases, grain sizes and quantities of residual molecules in the densified pellets, were characterized and explained. The formation of zinc acetate “bridges” was observed ex situ in hydrothermally sintered samples. A detailed ReaxFF molecular dynamics simulation was performed to help understand the formation mechanisms of zinc acetate “bridges” and compare the chemical activities between HS and CSP.

Mots clés: Molecular dynamics; ReaxFF; Ceramics; Cold sintering; Hydrothermal sintering; Molecular dynamics

Domaines: Matériaux

Arnaud Ndayishimiye, Mert Sengul, Sun Hwi Bang, Kosuke Tsuji, Kenji Takashima, et al.. Comparing hydrothermal sintering and cold sintering process: Mechanisms, microstructure, kinetics and chemistry. Journal of the European Ceramic Society, 2020, 40 (4), pp.1312-1324. ⟨10.1016/j.jeurceramsoc.2019.11.049⟩. ⟨hal-02506703⟩