The effects of cold sintering parameters on the densification of Na2WO4 ceramics using Na2WO4·2H2O dry powders |
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Authors: | Jianyu Hao Jing Guo Changli Fu Mingming Si Xian Xue Xiaomeng Li Hong Wang |
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Affiliation: | State Key Laboratory for Mechanical Behavior of Materials & School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, China |
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Abstract: | Cold sintering process (CSP) combines transient liquid phase and/or external pressure to assist the densification of ceramics, the sintering mechanism of which is typically dominated by the “dissolution–precipitation” process. In this work, Na2WO4·2H2O dry powders without liquid water have been used as the “liquid phase” to realize the densification of Na2WO4 ceramics. The effects of sintering parameters on the CSP of Na2WO4 ceramics using Na2WO4·2H2O dry powders are systematically studied, including sintering temperature, external pressure, sintering process time and the amount of Na2WO4·2H2O phase. It is found that the “liquid phase,” that is, Na2WO4·2H2O is the key factor for controlling the CSP of Na2WO4 ceramics, and Na2WO4·2H2O hydrate shows an advantage of homogeneous dispersion of liquid water. The sintering temperature affects the densification mechanism involved with plastic deformation and the “dissolution–precipitation,” external pressure accelerates the densification process, and enough sintering process time ensures the completion of CSP. Finally, the optimum cold sintering parameters of Na2WO4 ceramics by Na2WO4·2H2O powders are obtained at 150°C and 240 MPa for 60 min with a pretreatment at 150°C for 30 min. |
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Keywords: | cold sintering parameters cold sintering process microwave dielectric material Na2WO4·2H2O hydrate |
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