A new class of advanced materials
MAGNELI PHASE
OF TITANIUM SUB-OXIDES
Yibing Huang
Magneli Materials LLC
1
Table of Contents
● Summary
● Introduction to Magneli phase of Titanium sub-oxides
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Crystal structure feature
Key properties and their relation to structure
● Development History
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Atroverda and development of Ebonex
In-house synthesis
Atroverda process
Key challenges in the commercialization of Magneli phase
● Magneli Materials BREAKTHROUGH
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Mass production
Structural stablilization – a new class of MM
● Various studies and uses?
● Reference
2
Summary Page
● Breakthrough is the mass production of new Stabilized
Ti407
● High Corrosion Resistance in Acidic and Basic solutions
● Ceramic material with high electrical conductivity
● High electro chemical stability
3
Arne Magneli and Magneli Phase materials
●
Arne Magneli was one of the pioneers of
crystallography.
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Starting in the 1940’s, examined a variety of
transition metal oxides materials to determine why
they were lubricious and electrically conductive When they should have been neither.
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Early focus was Tungsten and Molybdenum sub-oxides
Later work included Titanium and Vanadium sub-oxides
He discovered that each featured dislocation planes
in their crystalline structure
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Established the study of transition metal sub-oxides and
shear plane dislocations
Paved the way for the discovery of conducting Titanates
and Pervoskites
Arne Magnéli
(1914-1996)
The dislocation planes accounted for their electrical
conductivity and lubricious properties
A similar mechanism gives rise to graphite and
graphene’s properties
These materials now called “Magneli Phase” materials
4
Titania Magneli Phase materials
 Magneli Phase sub-oxides of titanium
are ceramic materials which have a
graphite-like crystalline structure
otherwise known as a Magneli Phase.
 Magneli Phase sub-oxides of titanium
have individually identifiable X-ray
diffraction spectra and not simply
doped titania or casual mixtures of
TiOx.
 Magneli phase titanium sub-oxides are
a range of distinct compounds having
a general formula
TinO2n-1
(n=4 - 10)
(e.g. Ti4O7,Ti5O9,Ti6O11… )
5
Magneli Phase materials Crystal Structure
 The structures of Magneli phase
titanium oxides are based on, but
distinguishable from, the rutile TiO2
crystal structure
 They are all triclinic .
 The crystals of Magneli phase are
built up of TiO2 octahedra blocks
which share edges and corners to
form a slab and repeat in two
dimensions.
 In TinO2n-1, every nth layer has an
oxygen deficiency, which leads to
shear planes in the crystal structure.
 This shear plane occurs at n spacing
in the layers of octahedra. The higher
value of n has greater shear plane
interval.
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Ti4O7 is by far the best known and most
studied Magneli Phase material
●
The Shear Planes provide Magneli phase oxides the
pathway for the transfer of electrons and cause it to
be electrically conductive in a similar level to
graphite;
●
The layers of refractory Rutile octahedra blocks
provide it with chemical stability like TiO2;
●
Ti4O7 is the most reduced Magneli phase, It has
Rutile form of TiO2 with every 8th Oxygen removed;
●
Ti4O7 has the highest number of shear planes
occurring at the shortest spacing of these shear
planes
●
Ti4O7 has the highest electrical conductivity and
chemical stability among all Magneli phase of
titanium suboxides.
●
When the n equals to 3 or less, the shear plane
accommodation of the octahedra collapses and so
does the crystallographic structure from triclinic to
monoclinic.
7
Key properties of Magneli phase materials
●
Metal-like electrical conductivity
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Single crystal conductivity 1500 S/cm
Ceramic conductivity similar to graphite
8
Magneli Phase materials and Ebonex
●
●
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These materials were first
isolated in the late 1970’s by
Peter C.S. Hayfield while
working for Imperial Metals
Industries (IMI), a large UK
based producer of titanium
alloys.
Hayfield named the material
“Ebonex” after its deep blueblack color.
Ebonex has been ever since
produced by Atraverda, a UK
company.
9
Key properties of Magneli phase materials
●
Metal-like electrical conductivity
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The Magneli phase ceramic materials usually contain
a mixture of sub-stoichiometry.
Ceramic electrical conductivity is higher with low n values
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Key properties of Magneli phase materials
●
High corrosion resistance in aggressive acidic and basic solution
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Exceptionally robust in HF, BF4, PF6, HCl, KOH and other highly oxidizing
environments
Exceptionally stable under electrically polarized conditions that makes very
high performance anodes and cathodes
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Key properties of Magneli phase materials
●
High corrosion resistance in aggressive acidic and basic condition
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Only a few Magneli phase (Ti4O7/Ti5O9) have both high electrical
conductivity and chemical stability.
Other titanium suboxides are not as chemically stable as Magneli phase
even though with better electrical conductivity.
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Key properties of Magneli phase materials
●
Unique electrochemical properties
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Wide over-potential window that suppresses O2 and H2 evolution in water
Exceptional catalyst retention – superior adhesion, less catalyst require
Makes high performance cathode and anode
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Key properties of Magneli phase materials
●
Lubricious and high wear resistance
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Similar to graphite but with higher wear resistance
Makes as good wear and anti-scuffing coating as standard Mo-base coating
for inner-combustion engine piston ring .
14
Other properties of Magneli phase materials
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Super hydrophilic
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High microwave absorption
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Stronger absorption than
Silicon carbide
Wave guide and stealth
coating
Photo catalytic
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Drying agent
Electrical cable coating
Water split
Non-toxic and cost effective
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Environmental friendly
Abundance in natural and
relatively low cost
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Commercial Acceptance of Magneli Phase Materials
has been slow due to:
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Expensive to manufacture in bulk
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The Magneli Shear Planes are prone to
oxidation
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Ti4O7 can revert back to TiO2 when
exposed to some conditions
Shear Plane oxidation limits the forms
in which Ti4O7 can be effective
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Requires a 2 step process with chemical
reduction in a H2 filled furnace!
Nano-scale structures (fibers, films, high
surface area) are unstable
Very difficult to apply as a plasma
sprayed coating or PVD film
The Magneli Shear Planes are
Ti4O7‘s weakness - providing
access for re-oxidation to TiO2
Makes poor conductive polymers

Particle size and morphology cannot be
optimized for conductivity
16
Synthesis of Magneli Phase
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Reduction of high purity of TiO2 at
elevated temperature
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Hydrogen reduction
Carbon/graphite reduction
Ammonia reduction
Metallic titanium reduction
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Manufacturing of Magneli Phase – Atraverda, UK
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Two steps fire process:
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Make TiO2 ceramic body by conventional ceramic process;
Reduce the pre-fired porous ceramic body in hydrogen kiln to get mixed
Magneli phase titanium suboxides.
Crash and mill to get powder.
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Downsides of Atraverda manufacturing process
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Sophisticated equipment and process
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Long time, low efficiency
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Ceramic fire 1300C
Reduction 1100C
Inferior quality and low consistency
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Two fire process needs over 50 hours
Batch process for chemical reduction
Safety issue
 Hydrogen gas kiln
High energy consumption
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Whole ceramic production line
Hydrogen reduction production line
Hydrogen gas feed flow
Hydrogen gas diffusion in porous
ceramic body
High cost
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Products of Atraverda manufacturing process
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Products of Atraverda manufacturing process
XRD of Ebonex ceramic tube
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OUR MAGNELI Materials eliminate these issues
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We have developed a new manufacture process and novel class of
more advanced materials by through Structural Stabilization of the
Magneli Shear Planes
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Greatly expands the forms in which it can be made
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Resists conversion to TiO2 when exposed to strong oxidizing conditions
Micro and Nano-scale structure powders
Plasma sprayed coatings on low cost substrates (Ti , Al and stainless steel)
High surface area reticulated foams
Ceramic articles
Economical to manufacture in high volumes and consistency
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Our Magneli Material is a novel class of materials
● Substantially different from conventional Magneli Phase
materials
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Such as Ti4O7, Ti5O9, Ti6O11 and trade marked mixtures of these such as
Ebonex™
New material retains all documented properties of Ti407, with the
addition of being stable as nano-scale fibers and surface features.
Now possible to attain exceptional levels of effective potential
intercalation sites.
New material allows application as coating directly onto low cost foils
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Our Magneli Materials are superior
● Substantially higher content of Ti4O7
● Structural stabilized
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Commercial use of Magneli Phase materials is just starting
● extensive research and demonstration of significant
benefits from Stabized Ti407
● Primary applications :
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Energy storage
Electro Winning
Advanced Oxidation Process of water ?????????
Electro Winning
Cathodic Protection
Lubrication
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Our Mission
● Magneli Materials LLC was formed to address this
challenges by providing
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Volume supplies of high quality Magneli Materials in a
broad range of grades
A central point for the dissemination of research and
knowledge relating to Magneli Phase materials
Support for continued research in this area through
collaboration with
• Academic research groups
• Product developers and end users
● Our goal is to be the leading partner and supplier of
choice for Magneli Materials

We have brought together many of the prime movers in
this field and are expanding into the next generation of
researchers
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We have made substantial efforts to support our business
● Industrial scale production facilities
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Powder, ceramics, nano-structures
● Novel APS coating technologies
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Titanium, aluminum, stainless steel successfully coated
and functional as anodes
● Application of MnO2 and other catalysts
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New low cost catalyst options are now possible
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Currently available forms
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Powders - micron and nano-scale
Ceramics – plates and tubes
Coatings - Expanded Ti mesh
Conductive plastics – thermo-set
All can be supplied catalyzed or uncatalyzed
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1. Batteries and Fuel Cells
1.
“The continuing development of Magneli phase titanium sub-oxides and EbonexR electrodes, Walsh F.C. Wills
R.G.A. Electrochemical Acta, V55, Issue 22, 1st September 2012, p6342-6351
2.
Electrodes based on Magnéli phase titanium oxides: the properties and applications of Ebonex® materials by J
R Smith, F C Walsh, R L Clarke Journal of Applied Electrochemistry (1998) Volume: 28, Issue: 10, Publisher:
Springer, Pages: 1021-1033
3.
“Development of a new monolithic Ti4O7 Ebonex Ceramic, Hayfield P.C.S. Pub. Royal Society of Chemistry
ISBN 0854049843
4.
Ozone Generation at Ebonex and Ebonex / Lead Dioxide Electrodes'. Journal of Applied Electrochemistry 22,
200-203; Graves, J.E., Pletcher, D., Clarke, .R.L.
5.
Cr(III) oxidation with lead dioxide-based anodes Authors: Devilliers D.; Dinh Thi M.T.; Mahe E.; Le Xuan Q.
Electrochimica Acta, Volume 48, Number 28, 15 December 2003 , pp. 4301-4309(9)
6.
The electrochemistry of Magnéli phase titanium oxide ceramic electrodes Part I. The deposition and properties
of metal coatings. J. E. Graves, D. Pletcher, R. L. Clarke and F. C. Walsh, Journal of Applied Electrochemistry
Volume 21, Number 10 (1991), 848-857, DOI: 10.1007/BF01042450
7.
CSIRO Report Number DMP-098, Evaluation of the Effect of Ebonex® Additive on Lead-acid Battery Capacity
at Different Discharge Rates, August 1995
8.
Development of Supported Bifunctional Electrocatalysts for Unitized Regenerative Fuel Cells, G. Chen, S.R.
Bare, and T.E. Mallouk. Department of Chemistry, The Pennsylvania State University, University Park,
Pennsylvania, 16802, USA UOP LLC, Des Plaines, Illinois 60017, USA
9.
Lithium-Ion Intercalation into TiO2-B Nanowires† A. R. Armstrong, G. Armstrong, J. Canales, R. García, P. G.
Bruce Article, Advanced Materials Volume 17, Issue 7, pages 862–865, April, 2005
10. Structural properties of Ce-doped strontium titanate for fuel cell applications Denis J. Cumming , John A.
Kilner and Stephen Skinner J. Mater. Chem., 2011,21, 5021-5026 DOI: 10.1039/C0JM03680C
11. Synthesis of zinc titanate for Dye Sensitized Solar Cell (DSSC) application Azman bin Azumi, Azman (2010)
Synthesis of zinc titanate for Dye Sensitized Solar Cell (DSSC) application. Universiti Teknologi Petronas.
(Unpublished)
12. Moderate hydrothermal synthesis of potassium titanate nanowires. Z.-Y. Yuan, X.-B. Zhang and B.-L. Su.
APPLIED PHYSICS A: MATERIALS SCIENCE & PROCESSING Volume 78, Number 7 (2004), 1063-1066, DOI:
10.1007/s00339-003-2165-x
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1. Batteries and Fuel Cells (continued)
13. "Electrochemical Behavior of Platinized Ebonex® Electrodes". Int. J. Electrochem. Sci., 7 (2012) 7915 - 7926.
Authors: Olga Kasian, Tatiana Luk’yanenko, Alexander Velichenko (Ukrainian State University of Chemical
Technology, Gagarin ave. 8, 49005 Dnipropetrovsk, Ukraine); Rossano Amadelli (ISOF-CNR and Dipartimento
di Chimica, Università di Ferrara, via Borsari 46, Ferrara, Italy).
14. Development of Supported Bifunctional Electrocatalysts for Unitized Regenerative Fuel Cells
Guoying Chen (Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania,
16802, USA), Simon R. Bare, UOP LLC, Des Plaines, Illinois 60017, USA. Pub. Journal of The Electrochemical
Society, 149 A1092-A1099, 2002.
15. Stability of Corrosion-Resistant Magnéli-Phase Ti4O7-Supported PEMFC. Auth. Tsutomu Ioroi, Hiroshi
Senoh,Zyun Siroma, Shin-ichi Yamazaki, Naoko Fujiwara, and Kazuaki Yasuda. NIAIST, Japan. Pub. Catalysts
ECS Trans. 2007 11(1): 1041-1048
16. Fiber-like nanostructured Ti4O7 used as durable fuel cell catalyst support in oxygen reduction
catalysis. Chuanhao Yao, Fan Li, Xiang Lia (College of Environmental & Energy Engineering, Beijing University
of Technology, Pingle yuan 100, Beijing, P.R. China) and Dingguo Xia. (College of Engineering, Peking
University, Beijing 100871, P.R. China). Pub: J. Mater. Chem., 2012,22, 1656016565 DOI: 10.1039/C2JM32866F First published online 25 Jun 2012
17. Ti4O7 supported Ru@Pt core–shell catalyst for CO-tolerance in PEM fuel cell hydrogen oxidation reaction. Lei
Zhang, Jenny Kim, Jiujun Zhang, Feihong Nan, Nicolas Gauquelin, Gianluigi A. Botton, Ping He, Rajesh
Bashyam and Shanna Knights. Applied Energy, 2013, vol. 103, issue C, pages 507-513
18. Cortie, B., Xiao, L., Erdei, L.: `Thermal stability of (KxNayH1–x–y)2Ti6O13 nanofibers', Eur. J. Inorg. Chem.,
2011, 33, p. 5087-5095
19. Wang, C., Deng, Z., Li, Y.: `The synthesis of nanocrystalline anatase and rutile titania in mixed organic
media', Inorg. Chem., 2001, 40, p. 5210-5214
BSA 11-08: Nanoscale Magnéli Phases of Titanium Oxide Increase Electrode Capacity. BNL Reference
Number: BSA 11-08
20. Magneli phase Ti4O7 electrode for oxygen reduction reaction and its implication for zinc-air rechargeable
batteries. Xiaoxia Li, Aaron Li Zhu, Wei Qu, Haijiang Wang, Rob Hui, Lei Zhang, Jiujun Zhang Institute for Fuel
Cell Innovation, National Research Council of Canada, 4250 Wesbrook Mall, Vancouver, BC V6P 1W5,
Canada. Electrochimica Acta, Volume 55 Issue 20, August 2010 p58915898 http://dx.doi.org/10.1016/j.electacta.2010.05.041
30
2. Tribology
21. DE P 195 48 718 C1, Reibungsbelastetes Bauteil eines Verbrennungsmotors (Tribological stressed components
for internal combustion engines)
22. M. Woydt, “Review on Lubricious Oxides and Their Practical Importance In: Handbook of Surface Modifications
and Processing”: Physical & Chemical Tribological Methodologies, edited by: G.E. Totten; Marcel Dekker, New
York
23. M.N. Gardos. “The effect of anion vacancies on the tribological properties of rutile (TiO2-x)”: Tribology
Transactions, 1989, 32, 30-31
24. M.N. Gardos. “The effect of Magnéli Phases on the Tribological Properties of Polycrystalline Rutile”. Proc. 6th
Int. Congress on tribology, 1993, Vol. 3, p. 201-206
25. Woydt, M. , J. Kadoori, H. Hausner and K.-H. Habig. “Development of engineering ceramics according to
tribological considerations” (bilingual) Cfi/Ber. DKG, Vol. 67, No. 4, (1990), p.123-130 (Journal of the German
Ceramic Society)
26. O. Storz, H. Gasthuber and M. Woydt. “Tribological properties of thermal-sprayed Magnéli-type coatings with
different stoichiometries (TinO2n-1)”. Surface and Coatings Technology 140 (2000) 76-81
31
3. Water Treatment
27. “The Electrolytic Generation of Chlorine for the disinfection of private water supplies” Final Report, Contract
7/7/138, Project D.U. 194, University of Newcastle upon Tyne, UK 1991. Final Report to the UK Department of
the Environment
28. Electrolytic Cell for the Inactivation of Viruses in Water” Project DW I0743, University of Newcastle upon
Tyne, UK 1993, Final Report to UK Department of the Environment
29. Chemical Degradation Methods for Wastes and Pollutants: Environmental and Industrial Applications edited by
Matthew A. Tarr. CRC Press, Aug 8, 2003 - Science - 314 pages
30. Yang, D., Sarina, S., Zhu, H.: `Capturing radioactive Cs+ and I− from water with titanate nanofibers and
nanotubes', Angew. Chem. Int. Ed. Engl., 2011, 5, p. 10594-10598
31. Yang, D., Zheng, Z., Yuan, Y.: `Sorption induced structural deformation of sodium hexa-titanate nanofibers
and their ability to selectively trap radioactive Ra(II) ions from water', Phys. Chem. Chem. Phys., 2010, 12, p.
1271-127
32. "The use of Ebonex electrodes for the electrochemical removal of nitrate ion from water" Pub> Canadian
Journal of Chemistry, 2012, 90(8): 666-674, 10.1139/v2012-048. Auth: David Kearney, Dorin Bejan, Nigel
J. Bunce, Electrochemical Technology Centre, Chemistry Department, University of Guelph, Guelph, ON N1G
2W1, Canada.
32
Materials Handbook
– A concise Desktop Reference
33