NEXT GENERATION SINTERING
April 2021
Dr David Pearmain - Advanced Materials and Processes (AMP)
Next Generation Sintering….
− Flash Sintering and Scalability/ Applications
− Contactless Flash Sintering
− Cold/Flash Hybrid Systems
− Pressure Application and Flash Bonding
Electric Fields
What’s new in ceramics sintering? Latest trends and futureprospects
M. Biesuz, et al., Current Opinion in Solid State and Materials Science 24, 100868 (2020)
− Technologies developed after 2010 are highlighted in bold characters.
− A few possible technologies that might emerge in the next few years are
highlighted in purple italic characters.
− The “quaternary diagram of sintering”:
different sintering technologies with key
processing features: external heating
and pressure, presence of water and
electric fields/currents.
Flash Sintering
10 mm
− The application of electric fields to a ceramic during its sintering process to
instigate a Flash Event.
− Can be via:
− Contact or…
− Contactless electrodes.
Tim
e fo
r S
inte
rin
g (
s)
se
co
nd
sm
inu
tes
ho
urs
1
10
100
1000
10000
100000
Furnace Temperature
Conventional
Hot Press
SPS
Flash Sintering
Next Generation Sintering – Commercial Benefit
− Lucideon has developed world leading capability and experience in Flash
Sintering techniques for industrial application
− Activities involve increasing material performance & improving bond
between dissimilar materials
− Activities to increase productivity (significantly reduce sintering time >50%)
− Lucideon research for >9 years focusing on repeatability/ scalability and
commercialization
− Lucideon developed unique advanced real time control software
− Working with both academia and industry to develop scalable solutions
− People and facilities in both UK and USA
Host PC
1kHz real-time PC
Programmable power supply
Furnace
Electrode system
Ceramic
Low-voltage
High-voltage
Transformers
Control – the key to scalability of all new technology
− Real-time feedback on millisecond timescale
− Highly flexible and customisable
− DC to High Frequency AC.
Broad Range of Sintering Capabilities
Capability Suited for Case study
Control systemFast, repeatable densification
Property improvements
Technical ceramics / UHTC
Nuclear Fuels
High frequency Inhomogenous bodies Multi-phase materials
Adaptable electrical contact
Large thin bulk samples
Unusual geometries, e.g. tubes
Dynamic systems
Tileware
Beta-alumina
Ceramic/Metal joining
ContactlessCoatings
Large flat surfaces
Ceramic repair
Electrolyte/metal multilayers
Flash Bonding Joining dissimilar materials Armor and Aerospace
Cold/Flash Hybrid Refractory/Glass/Electroltye Work emerging
− Proprietary controller− Prevents flash-over− Homogeneity− Repeatability− Microstructural control
− Product enabler
Case study - technical ceramics (CIM alumina and YSZ)
FS- 9 min in 1050oC
furnace
FS- 83 min in 1050oC
furnace
Conventional
5 hr in 1500oC furnaceFS- 80 sec in 1050oC
furnace
20 um
Localization Homogeneous heating
Flash of CIM 3YSZ
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
800 1000 1200 1400 1600
Den
sit
y (
gr/
cm
3)
Furnace Temperature (oC)
− Comparable density
− Lower sintering temperature by 350°C and in
half the time.
Performance evaluation – enhanced properties
(conventional vs flash)
From Cho, J. et al. High temperature deformability of ductile flash-sintered ceramics via
in-situ compression. Nat Commun 9, 2063 (2018).
Case study – Frequency & Encapsulation
Example ‘Whiteware inert body and waste container glass’
− Higher densities achieved
− Increased productivity through reducing firing cycle.
Homogeneity achieved by high frequencies
Sample:
50mm x 50mm x 8mm commercial floor tile
LF HF
Sample:
10mm OD – 11mm thick
Flash for Nuclear Fuels: surrogate fuel (CeO2)
FS-1100ºC
CS-1600ºC30μm
30μm
− Microstructural control possible − Moving to Uranium Dioxide and MOx trials
A joint development with NNL and UoM for Advanced Fuels
Contactless flash – dealing with geometries & surface repair
− Glaze defects are a common issue for may ceramic industries
− Laborious, energy and time consuming repairs (24-36hr cycle at 1150ºC)
− Time reduced to less than 30 minutes in localized area.
Substrate glaze
Defect created
Defect filled
Defect repaired
Contactless flash sintering: continuing development
Single location, room
temperature operation -
spot defect repair
Mobile electrode,
variable temperature
ceramic on metal
Kiln
Multi-axis
Robot
Low temperature contactless sintering –
homogenous, large area sintering,
multiple electrode geometries
Further development and
scale up
Third generation contactless system
− Evolved to large surface area solid state electrolyte sintering on metals
− Hardware designed with low temp furnace surround for delta T control
− Integrated HV-electromechanical control algorithm
− Currently Sintering Ceramic Electrolyte layers and Multilayer systems on metals
− Robot has 100 micron resolution, with max acceleration of 100 ms-2.
Third generation contactless system
Fuel Source
3 axis robot
(Multi-axis optional)
Electrode head
assembly
Electrical panel
Real time PC
Function
generator
HV amplifier #1
HV amplifier #2
Contactless flash sintering in action
Control over the degree of sintering
Green Sintered
Joining dissimilar materials – product enabler
− First highlighted by our work on solid state electrolytes…
− Metal to Ceramic (inc. CMC) joining via FLASH BONDING
− Fundamental research is underway into EBC sintering technologies and the joining of dissimilar materials.
− For Armour, technology to address:− Light-weighting− Multi-hit capability (shunting)− Performance against medium and heavy platform threats
− Potential application for co-sintering of battery components for improved cell performance
Cold / Flash Hybrid systems – emerging developments
− As a new hybrid process, a combination between FS and CSP is emerging.
− Here, the presence of a liquid such as water (to ensure electric conductivity) within a
CSP apparatus connected to a power source allows to heat the ceramic powder up.
− Flash Cold Sintering (FCS) could therefore combine in a unique technique the
presence of solvent, electricity, extreme heating rates and pressure.
− Dramatically reduced sintering times and energy input….
A joint development with UoS and Industry / Innovate UK
“Hybrid Sintering for Decarbonisation and Productivity in Manufacturing”
−Lucideon, along with consortium partners
has received funding as part of the TFI
programme for the Hybrid Sintering project.
−The objective: To assess the possibility of
developing a process by employing both
Flash and Cold Sintering techniques
−To be used by the glass/ceramics sectors
offering benefits in resource and energy
efficiency.
Use of Electric fields in Next Generation Processing and
Ceramic Products
Multi-layer Ceramics
(SOFCs)
Joining of Dissimilar
Materials
Thermal/Environmental
Barrier Coatings
Solid State
Electrolytes
Sintering of Ceramic
Matrix Composite (CMCs)
Toughening of
Ceramics
Ceramic Armor
https://www.lucideon.com/uploads/pdfs/Nuclear-Engineering-International-September-2020.pdf
Other resources
Takeaway message
− Flash sintering is a powerful sintering technique and requires a robust and
sophisticated controller for scale-up and process management.
− Flash sintering can dramatically reduce sintering timescales from hours to minutes,
minutes to seconds
− Property enhancement due to flash sintering can be a product enabler
− Contactless glaze repair, joining dissimilar materials and microstructure control are
promising technologies for future development of flash sintering
− Cold/Flash Hybrid systems could be used to reduce energy consumption and speed to
incredibly low levels vs conventional techniques.
Thank you
Contact details
David Pearmain
T +44 (0)7793 000858
W www.lucideon.com
Dynamic Electrodes – Prototype Design
Commercial tile
Externally driven electrodes
How is FS different from SPS?
− FS is a pressureless technique, SPS under load in a graphite die
− Current flows through the sample in FS, in SPS through the highly
conductive die. Sintering mechanism different, and not entirely
known….
− Energy consumption lower by an order of magnitude in flash
− Flash has more scalable application given the absence of a die
and the utilisation of more continuous processing methods.