Effects of limiting current density and current step rate on microstructure and hardness of flash sintered MgAl2O4 ceramics

IF 5.8 2区材料科学 Q1 MATERIALS SCIENCE, CERAMICS

Journal of The European Ceramic Society Pub Date : 2024-10-11 DOI:10.1016/j.jeurceramsoc.2024.116982

Ning Han , Shoulei Yang , Shuyue Chen , Zhiyi Wang , Mengjie Yang , Lei Fan , Xiaoqing Guo , Yujin Dai , Yidan Wang , Shuangqing Chen , Zhengkai Zhang , Yun Zhang

{"title":"Effects of limiting current density and current step rate on microstructure and hardness of flash sintered MgAl2O4 ceramics","authors":"Ning Han , Shoulei Yang , Shuyue Chen , Zhiyi Wang , Mengjie Yang , Lei Fan , Xiaoqing Guo , Yujin Dai , Yidan Wang , Shuangqing Chen , Zhengkai Zhang , Yun Zhang","doi":"10.1016/j.jeurceramsoc.2024.116982","DOIUrl":null,"url":null,"abstract":"<div><div>This study investigates the effects of limiting current density and current step rate on the microstructure and hardness of current-step flash-sintered (CS-FS) disc-shaped MgAl<sub>2</sub>O<sub>4</sub> ceramics. The results indicated that, unlike conventional flash sintering, the temperature of the sample during the current-step flash started at a lower initial value and subsequently increased gradually. Furthermore, the differences in oxygen vacancies between the positive and negative sides of the CS-FS-ed MgAl<sub>2</sub>O<sub>4</sub> ceramics were significantly reduced. This led to the CS-FS samples exhibiting higher relative density, finer grain size, a more uniform microstructure, and increased hardness. The homogeneous microstructure resulted in consistent hardness across both sides of each CS-FS-ed sample. Additionally, as the limiting current density increased, the grain sizes near the positive and negative sides gradually enlarged, while the relative density initially increased before decreasing. A similar trend was observed when the current step rate decreased.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 116982"},"PeriodicalIF":5.8000,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of The European Ceramic Society","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0955221924008550","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, CERAMICS","Score":null,"Total":0}

引用次数: 0

Abstract

This study investigates the effects of limiting current density and current step rate on the microstructure and hardness of current-step flash-sintered (CS-FS) disc-shaped MgAl₂O₄ ceramics. The results indicated that, unlike conventional flash sintering, the temperature of the sample during the current-step flash started at a lower initial value and subsequently increased gradually. Furthermore, the differences in oxygen vacancies between the positive and negative sides of the CS-FS-ed MgAl₂O₄ ceramics were significantly reduced. This led to the CS-FS samples exhibiting higher relative density, finer grain size, a more uniform microstructure, and increased hardness. The homogeneous microstructure resulted in consistent hardness across both sides of each CS-FS-ed sample. Additionally, as the limiting current density increased, the grain sizes near the positive and negative sides gradually enlarged, while the relative density initially increased before decreasing. A similar trend was observed when the current step rate decreased.

查看原文本刊更多论文

极限电流密度和电流阶跃率对闪速烧结 MgAl2O4 陶瓷微观结构和硬度的影响

本研究探讨了限制电流密度和电流阶跃率对电流阶跃闪蒸烧结（CS-FS）盘形 MgAl2O4 陶瓷微观结构和硬度的影响。结果表明，与传统的闪蒸烧结不同，电流步进闪蒸过程中样品的温度从较低的初始值开始，随后逐渐升高。此外，CS-FS-ed MgAl2O4 陶瓷正负极之间的氧空位差异显著减小。这使得 CS-FS 样品表现出更高的相对密度、更细的晶粒尺寸、更均匀的微观结构和更高的硬度。均匀的微观结构使每个 CS-FS 样品的两面都具有一致的硬度。此外，随着极限电流密度的增加，正负极附近的晶粒尺寸逐渐增大，而相对密度则先增加后减小。当电流阶跃率降低时，也观察到类似的趋势。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of The European Ceramic Society 工程技术-材料科学：硅酸盐

CiteScore

10.70

自引率

12.30%

发文量

863

审稿时长

35 days

期刊介绍： The Journal of the European Ceramic Society publishes the results of original research and reviews relating to ceramic materials. Papers of either an experimental or theoretical character will be welcomed on a fully international basis. The emphasis is on novel generic science concerning the relationships between processing, microstructure and properties of polycrystalline ceramics consolidated at high temperature. Papers may relate to any of the conventional categories of ceramic: structural, functional, traditional or composite. The central objective is to sustain a high standard of research quality by means of appropriate reviewing procedures.