Studying the cold sintering process of zinc ferrite as an incongruent dissolution system

Abstract

AbstractIn this research, cold sintering process (CSP) was successfully applied for zinc ferrite. A Pechini‐type sol‐gel method was used to synthesize two types of powders, a single‐phase powder and a multiphase powder consisting of zinc ferrite, hematite, and zinc oxide. The powders were chemically treated in 12 M solution of acetic acid in ethanol. Our investigations indicated that zinc dissolves incongruently from zinc ferrite with respect to iron. Then, the chemically treated powders were mixed with 18‐21 weight percent (wt%) treatment solution to utilize for the CSP. Our studies indicated that the CSP of the chemically treated multiphase powder results in single‐phase zinc ferrite samples. Conversely, the CSP of the chemically treated single‐phase zinc ferrite powder led to samples having hematite as the secondary phase. The CSP at 350°C under 300 MPa uniaxial pressure for four hours and postannealing at 750°C for six hours resulted in samples with 93% relative density. Microstructure studies revealed that the samples under CSP were sintered with well‐defined grains and grain boundaries. This study is an introduction to develop the CSP for the sintering of technologically important transition metal ferrites.