Isolating Field Effects in Sintering via Ultrahigh Temperature In Situ Nanomechanics

通过超高温原位纳米力学隔离烧结中的场效应

• 批准号: 1922867
• 负责人: Shen Dillon
• 金额: $ 40.06万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-15 至 2022-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1922867&HistoricalAwards=false
• 关键词: Isolating; Field; Effects; Sintering; via

NON-TECHNICAL DESCRIPTION: Most ceramic products and devices originate from crystalline powders consolidated at high temperatures; a process called sintering. Traditional sintering typically requires a large input of energy, significant equipment costs, and relatively long manufacturing times. Application of electric fields during sintering can greatly reduce these costs and processing times. Unfortunately, electric field effects remain poorly understood owing in large part to (1) the great geometrical complexity of sintering and (2) a poor understanding of atomic motion and bonding at crystal surfaces where powder bonds during sintering. The lack of scientific understanding impairs engineers' ability to design optimal manufacturing conditions and produce new materials. This project develops a new methodology that efficiently isolates the physical properties of the material from particle geometry effects. As a result, unprecedented information about how electric fields affect bonding and atomic motion on surfaces can be obtained. This information can define which parameters are most important during electric field assisted sintering, and as a result, strategies to optimize manufacturing conditions. The work is technologically relevant to development of new ultrahigh temperature aerospace materials, advanced optical ceramics, and ceramics in microelectronics. The project supports the training of a graduate student in materials science and engineering. Graduates then typically work in industrial research laboratories in large manufacturing firms. The project also provides research opportunities for underrepresented high school students and pre-service teachers, and outreach activities targeted towards K-12 students. These activities are intended to attract students to science and engineering careers.TECHNICAL DETAILS: Electric fields can dramatically accelerate sintering kinetics, as is often observed during spark plasma sintering or flash sintering. However, the mechanisms underlying these processes remain highly controversial and poorly understood. The lack of fundamental knowledge derives from the complexity of the sintering process and the coupling of the electric field to all relevant diffusional and thermodynamic coefficients. The experiments isolate these effects by (1) measuring electrocapillarity coefficients of grain boundaries and surfaces in zirconia using a nanoscale zero creep experiment in applied fields, (2) quantifying electric field dependent grain boundary and surface diffusion coefficients via nanoscale single grain boundary Coble creep and surface smoothing experiments, respectively, and (3) controlling for anisotropy by using representative low and high energy bicrystal geometries. The work emerges from the development of novel ultra-high temperature in situ transmission electron microscopy based nanomechanical testing methods. The transformational impacts on the discipline are a new mechanistic understanding of electric field effects on sintering, new insights into field dependent interface thermodynamics in oxides, and the development of novel experimental methodologies useful for addressing many problems in ceramic science.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述：大多数陶瓷产品和设备都是由高温下固化的结晶粉末制成的;这一过程称为烧结。传统的烧结通常需要大量的能量输入、显著的设备成本和相对长的制造时间。 在烧结过程中施加电场可以大大降低这些成本和加工时间。不幸的是，电场效应仍然知之甚少，这在很大程度上是由于（1）烧结的几何复杂性和（2）对烧结过程中粉末结合的晶体表面处的原子运动和结合的理解不足。缺乏科学的理解削弱了工程师设计最佳制造条件和生产新材料的能力。该项目开发了一种新的方法，可以有效地将材料的物理特性与颗粒几何效应隔离开来。因此，可以获得有关电场如何影响表面上的键合和原子运动的前所未有的信息。这些信息可以定义在电场辅助烧结过程中哪些参数是最重要的，从而确定优化制造条件的策略。这项工作在技术上与新型低温航空航天材料、先进光学陶瓷和微电子陶瓷的发展有关。 该项目支持材料科学和工程研究生的培训。毕业生通常在大型制造企业的工业研究实验室工作。该项目还为代表性不足的高中学生和职前教师提供研究机会，并针对K-12学生开展外联活动。这些活动旨在吸引学生从事科学和工程职业。技术优势：电场可以显著加速烧结动力学，这在放电等离子烧结或闪速烧结过程中经常观察到。然而，这些过程背后的机制仍然存在很大的争议和知之甚少。基本知识的缺乏源于烧结过程的复杂性和电场与所有相关扩散和热力学系数的耦合。这些实验通过以下方式分离这些效应：（1）在外加场中使用纳米级零蠕变实验测量氧化锆中晶界和表面的电毛细系数，（2）分别通过纳米级单晶界Coble蠕变和表面平滑实验量化电场依赖性晶界和表面扩散系数，以及（3）通过使用代表性的低能量和高能量双晶体几何形状来控制各向异性。这项工作出现在新的超高温原位透射电子显微镜为基础的纳米力学测试方法的发展。对该学科的变革性影响是对电场对烧结影响的新的机理理解，对氧化物中场依赖界面热力学的新见解，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查进行评估来支持的搜索.

项目成果

Ultrahigh temperature in situ transmission electron microscopy based bicrystal coble creep in Zirconia II: Interfacial thermodynamics and transport mechanisms

• DOI: 10.1016/j.actamat.2020.08.070
• 发表时间: 2020-11-01
• 期刊: ACTA MATERIALIA
• 影响因子: 9.4
• 作者: Grosso, Robson L.;Vikrant, K. S. N.;Dillon, Shen J.
• 通讯作者: Dillon, Shen J.

Evidence for Interface-Rate Limited Densification Kinetics at Al2O3-GdAlO3 Interfaces Characterized by in situ Ultrahigh Temperature Transmission Electron Microscopy

• DOI: 10.1016/j.jeurceramsoc.2022.06.001
• 发表时间: 2022-06
• 期刊: Journal of the European Ceramic Society
• 影响因子: 5.7
• 作者: D. Coffman;Yong Ma;C. Barr;J. Ouyang;K. Hattar;S. Dillon

Interphase Boundary, Grain Boundary, and Surface Diffusion in Al2O3-GdAlO3 Composites Determined from Bicrystal Coble Creep Experiments

• DOI: 10.1016/j.jeurceramsoc.2022.02.052
• 发表时间: 2022-03
• 期刊: Journal of the European Ceramic Society
• 影响因子: 5.7
• 作者: D. Coffman;Yong Ma;C. Barr;J. Ouyang;K. Hattar;S. Dillon

Ultrahigh temperature in situ transmission electron microscopy based bicrystal coble creep in zirconia I: Nanowire growth and interfacial diffusivity

基于超高温原位透射电子显微镜的氧化锆双晶铜线蠕变 I：纳米线生长和界面扩散率

• DOI: 10.1016/j.actamat.2020.08.069
• 发表时间: 2020
• 期刊: Acta Materialia
• 影响因子: 9.4
• 作者: Vikrant, K.S.N.;Grosso, Robson L.;Feng, Lin;Muccillo, Eliana N.S.;Muche, Dereck N.F.;Jawaharram, Gowtham S.;Barr, Christopher M.;Monterrosa, Anthony M.;Castro, Ricardo H.R.;García, R. Edwin
• 通讯作者: García, R. Edwin

Unraveling the Role of Grain Boundary Anisotropy in Sintering: Implications for Nanoscale Manufacturing

• DOI: 10.1021/acsanm.1c01322
• 发表时间: 2021-07-19
• 期刊: ACS APPLIED NANO MATERIALS
• 影响因子: 5.9
• 作者: Hussein, Omar;Alghalayini, Maher;Abdeljawad, Fadi
• 通讯作者: Abdeljawad, Fadi