Flash Sintering of Composite Ceramic Materials and Structures

Lead Research Organisation: University of Warwick
Department Name: WMG

Abstract

Ceramic materials are used in a wide range of applications including motion sensors, for energy storage in electric vehicles, dental replacement, hip and knee implants, cutting blades, and body and vehicle armour. They are exceptionally durable, even at high temperatures and in corrosive environments, and can be reused or recycled at the end of their life. However the high cost of manufacturing is a major barrier to the use of ceramic materials. Producing a dense strong ceramic material with minimal porosity requires heating to very high temperatures well over 1000 deg.C typically for many hours.

Recently scientists have discovered that the temperature and duration of the ceramic densification process (sintering) can be significantly reduced by passing an electric field through the ceramic during the heating process. This "flash sintering" process, so-called because the material densifies extremely rapidly within a few seconds and often with the simultaneous emission of light, has potential to significantly reduce energy use in industrial-scale ceramic manufacturing and reduce emissions of greenhouse gases from the process by up to 40%. The flash sintering technique may revolutionise the ceramic manufacturing industry by reducing the cost and environmental impact of producing ceramic materials.

In this research project a detailed investigation of the flash sintering method will be undertaken to establish the viability of this technique for use with a wide range of ceramic materials and particularly to understand the underlying mechanisms which cause the flash sintering effect. A flexible flash sintering facility will be established which can be used to flash sinter a wide range of ceramic materials. Composite materials with varying electrical conductivity will be flash sintered under different conditions. The results will used to understand the effect of both the material properties and the variables involved in the process (e.g. electric field strength, current, voltage, and temperature) on the observed flash sintering behaviour. Materials will be characterised by measuring their density, imaging using scanning electron microscopy and mapping the chemical composition, and using X-ray diffraction to determine any changes to the phase composition of the materials caused by the flash sintering process. New insights will be gained by flash sintering for the first time a structure made of layers of ceramic composite materials graded by composition and examining how the flash sintering behaviour changes compared to samples containing each individual composition. The results of this project will be used by our industrial project partners Lucideon and Morgan Advanced Materials in the industrial development and application of flash sintering technology.

Planned Impact

The use of flash sintering of ceramic materials in the ceramic manufacturing industry is currently limited by a lack of understanding of the underlying driving forces for the process across a range of materials. By conducting this in-depth investigation of the effect of composition-based bulk property variations on the efficacy of flash sintering in composite ceramic materials and structures, this project will result in increased understanding of the underlying mechanisms of flash sintering in ceramic materials. As a result this project will facilitate future efforts to tailor the composition of ceramics to enable flash sintering, and so directly contribute to the wider use of flash sintering technology in ceramic manufacturing.

The UK ceramics industry employs 20,000 people directly and has sales of £2bn per year. Ceramics are also essential supporting technology for industries such as steel and glass production, petrochemicals, and renewable electricity production and distribution. The reduced costs enabled by flash sintering will result in greater use of ceramic materials and components. This project is supported by Lucideon, an SME at the leading edge of industrial-scale developments in flash sintering technology, and Morgan Advanced Materials, one of the largest ceramic manufacturing companies in the world. For both these companies, the research proposed in this project will lead to new insights directly relevant to their ceramic manufacturing business. In addition to engaging with the project partners, the research team will communicate their findings to other companies within the ceramic supply chain through presentations at UK and international conferences, using a project website to disseminate research findings, and through the High Value Catapult (of which the host department is a Centre) who will showcase the technology developed in this project.

The adoption of flash sintering by the ceramic manufacturing industry will also reduce CO2 emissions, necessary for the UK's greenhouse gas emission reduction goal for the 2015 Paris Climate Agreement. Energy use in the industry would also be significantly reduced, estimated at around 40% for tile manufacturing, for example, lowering the cost of producing ceramic materials. As applications requiring ceramic materials include healthcare (dental and joint replacement) and defence (body and vehicle armour), not only are there positive implications for the ceramic manufacturing industry but also for patients of the NHS and soldiers serving in the UK Armed Forces, as the reduced costs may enable more widespread availability of lifesaving ceramic implants and armour.

Involvement in this project will benefit the research team by gaining technical experience in the flash sintering process and through the experience of interacting with industrial and academic partners and collaborators, presenting at national and international conferences, and writing technical documents including journal articles to disseminate the research findings. The research in this project will also be incorporated into the applicant's teaching on the undergraduate Engineering course and the MSc in Manufacturing Systems Engineering at the University of Warwick. Individual projects and internships (at Warwick or with SMEs) will be offered on flash sintering topics, encouraging more students to consider a future career in ceramic manufacturing and related sectors. MSc students studying Manufacturing Systems Management and Supply Chain Management will be recruited for projects on the Life Cycle Analysis of ceramics manufacturing using flash sintering. In addition, bespoke Outreach activities on ceramic materials manufacturing will be developed and delivered by the project team at science festivals and local schools. These educational activities will result in a greater number of students graduating with knowledge and experience relevant to the ceramic manufacturing industry.

Publications

10 25 50
 
Description In this work we discovered the process parameters for densifying certain ceramic materials using a process called flash sintering. Using this process we can (i) significantly reduce the energy consumption of the densification process and (ii) densify materials at lower temperatures and in contact with metals which would usually melt. We have also investigated the extent to which the materials vary in their microstructure following flash sintering and examined ways to mitigate this using multiple electrodes, different materials, and different ways of carrying out the flash sintering process e.g. AC vs DC electric field, and contact vs contactless application of electric field. Further research questions relating to whether flash sintering can be applied more broadly to low-ionic conductivity ceramics have been developed as a consequence of this work. This project has supported the training of two people, one of whom has gone on to a senior role in industry of a related company.
Exploitation Route The outcomes of this work may be taken forward in a number of ways. First, to apply the flash sintering techniques used to a wider range of materials, including some with less ionic conductivity than those used in this work. We will tackle this ourselves in a follow-on grant. Secondly, by using these techniques at a larger scale we can move towards using flash sintering for pilot-scale production of ceramic material devices such as solid state batteries. Thirdly the initial findings around the origin of inhomogeneities in flash sintered ceramics can be expanded and further developed in the future to mitigate this problem which may otherwise limit the applicability of the technique.
Sectors Energy

Manufacturing

including Industrial Biotechology

 
Description Our findings in this work have had particular impact on our partner company Lucideon who have used this work (along with other projects) to justify investment in new facilities and technologies in the UK. This includes developing new and scaled-up flash sintering facilities tailored to the needs of some of the materials studied in this grant, and recruiting employees to work on this technology.
First Year Of Impact 2023
Sector Energy,Manufacturing, including Industrial Biotechology
Impact Types Economic

 
Description European Regional Development Fund "Smart Energy Network Demonstrator" based at Keele University, supported by Lucideon Ltd.
Amount £61,217 (GBP)
Funding ID 32R16P00706 
Organisation Keele University 
Sector Academic/University
Country United Kingdom
Start 09/2018 
End 09/2021
 
Description Sintering Ceramics at Room Temperature using Phase-Changing Additives
Amount £248,153 (GBP)
Funding ID EP/X019055/1 
Organisation University of Warwick 
Sector Academic/University
Country United Kingdom
Start 03/2023 
End 03/2025
 
Description Lucideon Ltd and Warwick Manufacturing Group 
Organisation Lucideon
Country United Kingdom 
Sector Private 
PI Contribution This partnership with Lucideon has involved so far a jointly funded PhD position at the University of Warwick, the student is now employed as a Senior Scientist at Lucideon due to the value of the skills he developed while working in the area associated with this grant. The grant also benefited significantly from access to the Lucideon flash sintering facilities.
Collaborator Contribution Lucideon have provided access to their facilities and expertise, including working on site at their premises. They have also employed the PhD student. They have already agreed a further PhD studentship to start in October 2022 at the University of Warwick.
Impact Joint papers and joint presentations at conferences, detailed under relevant sections.
Start Year 2018
 
Description Press release 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Press release on our work on flash sintering, particularly as related to our recent MRS Bulletin article. Only recently issued but interest from professional/industrial news sources and via social media.
Year(s) Of Engagement Activity 2021
URL https://warwick.ac.uk/newsandevents/pressreleases/solid-state_batteries_could