next generation sintering · third generation contactless system −evolved to large surface area...

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

E david.pearmain@lucideon.com

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.

Thank you

Contact details

T +44 (0)1782 764403

E david.pearmain@lucideon.com

W www.lucideon.com