Processing of Nanostructured Ceramics

Lead Research Organisation: Loughborough University
Department Name: Materials

Abstract

The appeal of nanocrystalline ceramics arises from their potential to offer unusual physical and mechanical properties, which, depending on the material, can include superplasticity at elevated temperatures, optical transparency for normally opaque materials and a range of other electrical, optical and magnetic properties as well as potentially higher strengths, toughnesses and hardness.Although some commercial nanopowders are now produced in relatively large quantities, consolidation into dense nanostructured components by industrially-viable routes is needed to take full advantage of the potential offered. If this can be achieved there is the potential to use the materials for a very wide range of applications. Advanced ceramics are the active material in many electronics devices, fuel cells, magnets, sensors and biomaterials, as well as a very wide range of structural components. This means that they are used in almost every type of industry, including power generation, aerospace, transportation and military applications as well as in the manufacture of other materials. Such applications are vital to maintaining global competitiveness, decreasing energy consumption and minimising pollution. Their estimated world market was >$20B in 2000, with an annual growth rate of 7.2%. Of this, the electronics sector was ~65% of the market, the rest falling into the chemical processing, coatings and advanced structural mechanics sectors.The primary objective of this research proposal is to develop a number of recent developments at Loughborough Univ. that have been achieved under previous EPSRC grants. Specifically:* Whilst it is now possible to slip cast very homogeneous and high density compacts from nanosuspensions, there is currently a major problem with drying those made from high solids content suspensions (which yield the best bodies) - it can take several days even using a humidity drier. The structure of these bodies need understanding as a function of the processing conditions used, particularly the solids content of the suspension. This then gives us a chance to control the situation and perhaps improve it so that drying times can be much faster without sacrificing the properties of the body.* Similarly, it is now possible to dry press homogeneous and high density compacts from powders that have been formed by spray-freeze drying the nanosuspensions (the same process used to make instant coffee granules). Once again, however, the high solids content suspensions (which yield the highest densities) provide problems, this time with hard agglomerates that don't crush. Very similar work needs performing as above to allow us to understand why this is happening and what can be done about it.* Both types of compact need firing in furnaces to produce fully dense ceramics whilst retaining an extremely fine, sub 100 nm, average grain size. Whilst this can now also be done using a novel pressureless (and hence low cost) process, the understanding of how this process works is still not perfect and we also need to scale up to make larger components.* Finally, as we near the point where we can exploit these developments commercially, we really need to develop a better understanding of industry's requirements. Just how close are we to developing process routes that they can use on their factory floors? Which ceramic systems are they most interested in? Which companies are really ready to embrace the new 'nanotechnology' and which are keen to sit on the sidelines for a bit longer yet. These issues, and others, will all be addressed in the final task of the programme.

Publications

10 25 50
 
Description The primary objective of this research proposal was to develop a number of recent developments at Loughborough Univ. that have been achieved under previous EPSRC grants. Specifically:

* It has been learnt how to slip cast bodies as large as 60 mm in diameter (dried green body) without cracking. In part this is down to the rheology of the slip used (60 wt% solid content, 0.2 Pa s nanosuspension), to the choice of grade of plaster of Paris and to the drying conditions used. The green bodies formed are typically ~55% of theoretical density, which is sufficient to be able to sinter them to full density without undue grain growth.

* It has been learnt how to produce a flowable, completely crushable granulated nanopowder. The flowability matches that of a benchmark, commercial, submicron yttria stablised zirconia; the granules now crush at as little as 200 MPa (previously at least 380 MPa). The new, lower strength granules are now well within range of existing ceramic processing equipment on the factory floor. The primary key has been the introduction of an agent designed to introduce flaws into the granules and hence weaken their strength. A patent application was filed on this process (Oct 08).

* We are now able to densify both the above green bodies to at least 99.5% of theoretical density whilst retaining a mean grain size anything from ~65 nm up to ~200 nm. These results have given us the ability to actually measure the properties of these ceramics. In brief, we have discovered that they are as strong as commercial ceramics (measurements made by NPL - strengths of ~1 GPa); they can be a lot more damage resistant (indentation toughness measurements up to 14.5 MPa m-1/2) and they can be entirely resistant to hydrothermal ageing (3 weeks at 250oC, 4 bar; conventional YSZ disintegrates completely within 1 hr under these conditions). A patent has been filed (Nov 08) on the properties.

* A full market survey has been completed by an independent body, viz. CERAM Research in the UK. Undertaken before we could release the property data, it provided confirmation of the significant interest in our work. Numerous companies were interested provided a) the properties were good (we now know that they are) and b) the various steps can be scaled up (they can).
Exploitation Route The work undertaken here has been further extended via a Collaboration Fund programme and was subsequently licensed to MEL Chemicals in February 2012. Commercialisation is expected during 2012/13.
Sectors Energy

 
Description This research led to a series of subsequent research grants and the processes developed have been licensed by MEL Chemicals.
First Year Of Impact 2009
Sector Aerospace, Defence and Marine,Energy,Environment
Impact Types Economic

 
Description EPSRC Collaboration Fund - Manufacture of prototype nanostructured ceramic components
Amount £100,780 (GBP)
Funding ID EP/I500227/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 04/2010 
End 12/2011
 
Description HIRF - Manufacture of nanostructured ceramics
Amount £16,309 (GBP)
Organisation ENVEO 
Sector Private
Country Austria
Start 09/2007 
End 02/2008
 
Description KTA - Nanostructured ceramics for dental applications
Amount £48,312 (GBP)
Organisation Loughborough University 
Sector Academic/University
Country United Kingdom
Start 09/2011 
End 10/2012
 
Description Loughborough Univ - Enterprise Fellowship
Amount £16,296 (GBP)
Organisation Loughborough University Enterprises Ltd 
Sector Private
Country United Kingdom
Start 12/2007 
End 11/2008
 
Description Loughborough Univ Enterprise Office - Bridging funds for postdoc
Amount £8,487 (GBP)
Organisation Loughborough University 
Sector Academic/University
Country United Kingdom
Start 12/2011 
End 03/2012
 
Description Loughborough Univ Enterprise Support - patent costs
Amount £25,000 (GBP)
Organisation Loughborough University Enterprises Ltd 
Sector Private
Country United Kingdom
Start 03/2008 
End 09/2008
 
Description Loughborough Univ research studentship - Transparent nanocrystalline YAG
Amount £51,570 (GBP)
Organisation Loughborough University 
Sector Academic/University
Country United Kingdom
Start 09/2010 
End 09/2013
 
Description Manufacturing nanostructured ceramics: new process for concentrating nanosuspensions via an industrially viable route
Amount £12,983 (GBP)
Organisation Loughborough University 
Sector Academic/University
Country United Kingdom
Start  
 
Description Morganite Electrical Carbon Ltd - Transparent nanocrystalline YAG
Amount £45,000 (GBP)
Organisation Morgan Advanced Materials 
Department Morganite Electrical Carbon Ltd
Sector Private
Country United Kingdom
Start 09/2010 
End 09/2013
 
Description Nano transparent alumina
Amount £50,000 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 09/2012 
End 03/2015
 
Description Nano transparent alumina
Amount $66,000 (USD)
Organisation ONRG Office of Naval Research Global 
Sector Public
Country United States
Start 09/2012 
End 03/2015
 
Description Nanoplant
Amount £358,390 (GBP)
Funding ID EP/L024780/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 04/2014 
End 04/2017
 
Description Royal Soc - Scaling up the production of nanostructured ceramics
Amount £29,375 (GBP)
Organisation The Royal Society 
Department Brian Mercer Feasibility Award
Sector Charity/Non Profit
Country United Kingdom
Start 04/2009 
End 02/2011
 
Description TSB - Nanostructured advanced ceramics
Amount £218,811 (GBP)
Funding ID TS/G000891/1 
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 09/2008 
End 12/2011
 
Description TSB - Nanozirconia for ceramic implants
Amount £206,020 (GBP)
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 09/2011 
End 09/2013
 
Description Dynamic-Ceramic Ltd 
Organisation Dynamic-Ceramic Ltd
Country United Kingdom 
Sector Private 
PI Contribution Further collaboration was undertaken utilising the following funding: EPSRC Collaboration Fund EP/I500227/1 Royal Society Brian Mercer Feasibility Award Loughborough University funding KTA funding Direct industrial funding All of which extended this project further. Partners included MEL Chemicals, Dynamic Ceramic Ltd and Valve Solutions amongst others.
Collaborator Contribution Dynamic-Ceramic put our nanopowder through their production line to make ceramics - it worked.
Impact None to date.
Start Year 2007
 
Description MEL Chemicals 
Organisation MEL Chemicals Inc
Country United States 
Sector Private 
PI Contribution Further collaboration was undertaken utilising the following funding: EPSRC Collaboration Fund EP/I500227/1 Royal Society Brian Mercer Feasibility Award Loughborough University funding KTA funding Direct industrial funding All of which extended this project further. Partners included MEL Chemicals, Dynamic Ceramic Ltd and Valve Solutions amongst others.
Collaborator Contribution They provided the precursor nanosuspension
Impact They have commercialised their process
Start Year 2007
 
Description Rolls-Royce Fuel Cell Systems Ltd 
Organisation Rolls Royce Group Plc
Department Rolls-Royce Fuel Cell Systems Limited
Country United Kingdom 
Sector Private 
Start Year 2007
 
Description Valve Solutions 
Organisation Valve Solutions
Country United Kingdom 
Sector Private 
PI Contribution Further collaboration was undertaken utilising the following funding: EPSRC Collaboration Fund EP/I500227/1 Royal Society Brian Mercer Feasibility Award Loughborough University funding KTA funding Direct industrial funding All of which extended this project further. Partners included MEL Chemicals, Dynamic Ceramic Ltd and Valve Solutions amongst others.
Collaborator Contribution Valve Solutions tested the final product.
Impact None to date.
Start Year 2007
 
Title METHOD FOR CONCENTRATING NANOSUSPENSIONS 
Description A method for concentrating a nanosuspension comprising nanopowder particles suspended in a liquid comprises reducing the liquid content of the nanosuspension and controlling the dispersion of the nanopowder particles in the liquid. 
IP Reference WO2006136780 
Protection Patent granted
Year Protection Granted 2006
Licensed Yes
Impact Sales are beginning to happen.