Dr Steven Milne
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Dr Steven Milne Reader in Ceramic Science |
Lead-free Piezoelectric Ceramics
With T P Comyn and A J Bell
Environmental legislation has stimulated intense international research activity into developing alternative, lead-free piezoelectric ceramicss. Piezoelectrics interconvert mechanical and electrical energy. Applications include sonar, ultrasound medical imaging, piezoelectric motors, sensors and actuators. Piezoelectrics are also of interest for energy harvesting applications, for example generating electricity from the mechanical vibrations of machinery, or from footsteps.
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Hydrothermally prepared sodium niobate powder |
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Lattice parameters as a function of temperature for NKN-7% LT ceramic |
Strain-Field loops |
Current PhD Research Projects
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Start Date: October 2005 |
Sodium Potassium Niobate based piezoelectrics
Relationships between crystal structure and piezoelectric properties are being evaluated. The emphasis is on the binary system sodium potassium niobate-lithium tanatalate, Na0.5K0.5NbO 3-LiTaO3. Novel systems are also being evaluated. Materials with comparable properties to certain PZT compositions have been demonstrated, for example: mechanical strains of 0.2 %, d33 charge coefficients of ~ 200 pV/m and Curie temperatures of ≥ 450 ºC with a stable operating temperature range of -15 to +300 ºC .
Publications
Temperature stability of ([Na0.5K0.5NbO3]0.93 – [LiTaO3]0.07) lead-free piezoelectric ceramics, T. A. Skidmore, T. P. Comyn and S. J. Milne, Appl Physics Letts ( in press) 94(22) Art. No. 222902 01 Jun 2009
Phase development during mixed-oxide processing of a [Na0.5K0.5NbO3](1-x)[LiTaO3](x) powder, T. A Skidmore and S J Milne J Mat. Res. 22 2265-72 (2007).
Phase development during mixed-oxide processing of a [Na0.5K0.5NbO3](1-x)[LiTaO3](x) powder, T A Skidmore, T Stevenson, T P Comyn and S J Milne, High Performance Ceramics V, PTS 1&2 368-3721886-1889 2008
Conference Presentations
CICC 2008 (China); Electroceramics XI (England); Piezo 2009 (Poland).
Visiting studentship
4 months spent at Wuhan University,China
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Start Date: October 2007 |
Sodium Bismuth Titanate based piezoelectrics
Structural analysis of the binary solid solution between sodium and potassium bismuth titanates is being collated to ferroelectric and dielectric properties. The project benefirs from access to synchrotron X –ray diffraction and neutron diffraction facilities. The overall aim is to develop an improved understanding of the key factors controlling properties. An examination of the effects of dopants on domain mobility forms part of the study.
Conference Presentations
Electroceramics XI (England); Piezo 2009 (Poland)
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Start Date: November 2008 |
Lead-free Piezoelectrics for Energy Harvesting Applications
Sodium potassium niobate materials are under investigation for powering sensors in automotive and other applications. Process and compositional opyimisation is followed by construction of prototype devices for evaluation against PZT.
Conference Presentations
IMF-ISAF (2009)
Nano Biomaterials
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Hydrosyapatite nano powder prepared by hydrothermal route (top) and sol-gel route (bottom) |
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Schematic section of human tooth: exposed channels running through dentine are cause of sensitive teeth |
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Section of human dentine |
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Dentine section infiltrated by nane hydroxyapatie particles |
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3D reconstruction of dentine tubules from SEM sections obtained by FIB-SEM |
Current PhD Research projects on Nano Biomaterials
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Start Date: October 2008 |
Syntheses and TEM characterization of Hydroxyapatite Nanoparticles
A protocol is being developed for the reliable characterization of nanoparticle hydroxyapatite using high resolution TEM with EDX chemical analysis facility. Sol-gel and hydrothermal synthesis routes are employed to prepare a range of particle sizes and shapes. Compositional modifications are also under investigation.
Recently Completed PhD Projects
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Current Location: GlaxoSmithKilne, London |
Nanoparticles for Dentine Infiltration
Nanoparticle hydrozyapatite particles, produced by hydrothermal routes, were used to infiltrate sections of human dentine. The purpose was to evaluate the effect of the particles in blocking the channels in dentine in order to prevent fluid motion. In the long term this approach may offer a n effective means of treating sensitive teeth.
Publications
J S Earl, D J Wood, S J Milne. “Dentine infiltration - A cure for sensitive teeth”. Amer. Cer. Soc. Bulletin. 85,22-5 (2006).
J S Earl, D J Wood, S J Milne. “Hydrothermal synthesis of hydroxyapatite”. Journal of Physics: Conference Series. 26, 268-271 (2006).
Nanoparticles for Dentine Tubule Infiltration: an In Vitro Study
J S Earl, D J Wood, S J Milne J Nanoscience and Nanotechnology (in press)
Thin and Thick Film Functional Ceramics
Current PhD Research Projects
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Start Date: October 2006 |
Laser Transfer Processing for the Integration of Ferroelectric Materials
It is possible to fabricate a ferroelectric film at high temperatures on a substrate such as sapphire and release the film for bonding to a substrate that cannot withstand typical ferroelectric process temperatures by directing a pulsed UVlaser beam through the transparent sapphire onto the absorbing film. This laser transfer process (LTP) opens up the possibility of integrating ferroelectrics with semiconductors and polymers which cannot sustain the high process temperatures required to fabricate a ferroelectric film. The project is part of a larger EPSRC Flagship project with Imperial College and Cranfield University developing System in Package devices for mobile communications.
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Optical stage for eximer laser irradiation of ferroelectric film on sapphire substrate |
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Preparation of film section for TEM analysis of laser-generated damage |
Publications
Laser transfer processing of functional ceramic films C.W. James, T. Comyn, R. Dorey, D Underhill, S J Milne J Eur. Cer. Soc. (in press)
Laser Transfer Processing for the Integration of Thin and Thick Film Ferroelectrics
C James, T Chakraborty, A Brown, , T Comyn, R Dorey,
J Harrington, A J Laister, R E Miles, C Puchmark , B Xu, W Xiong, Q Zhang, S J Milne. J Mat Sci Special edition (in press)
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“Characterization of laser-transferred bismuth ferrite lead titanate ferroelectric thick films”. T P Comyn, T Chakrabory, R E Miles, S J Milne Appl. Phys. Lett., 93 Art No. 052909 (2008).
Conference Presentations
Electroceramics X (Spain); Electroceramics XI England; Piezo 2009 (Poland); IMF-ISAF 2009 (China)
Collaborators
R E Miles, A Laister (School of Electronic and Electrical Engineering). Q Zhang, R Dorey (Cranfield University)
Sol-gel thin films of PZT and NKN
Sol-gel methods are being investigated for producing thin films of sodium potassiujm niobate - a lead-free piezoceramic composition.
Publications
A Chowdhury, P R Thompson, S J Milne. “TGA-FFIR study of a lead zirconate titanate gel made from a triol-based sol-gel system”. Thermochim Acta 475, 59-64 (2008).
A Chowdhury, M A Khan, C James, S J Milne. “Densification and enhanced polarization in lead zirconate titanate sol-gel thin films” Mater. Chem. Phys. 113, 135-139 (2009).
A Chowdhury, S O’Callighan, T A Skid more, C James, S J Milne. Nanopowders of NKN Prepared by the Pechini Method J Amer. Ceram. Soc. 92 758-761 (2009)
Conferences
Electroceramics XI (England)