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Reports on Industrial Group Meetings 2003
BCA Spring Meeting15-16th April 2003, YorkAn Introduction to Powder Diffraction and Phase Identification Workshop15-16 April, 2003 Organisers: Judith Shackleton and Dave Taylor with principal speaker, John Faber. This session started on Tuesday afternoon with a most useful refresher on the basic theory of powder diffraction - much of which I remembered I'd forgotten! With "An Introduction to X-ray Powder Diffractometry" by Ron Jenkins & Robert L. Snyder (John Wiley & Sons) being used as the major reference source. It began at the very beginning with Laue photographs of single crystals and powders and from here went on to describe the unit cell, fractional co-ordinates, crystal systems, the 14 Bravais Lattices and Space Groups. We then "learnt" about calculated density vs. measured density, lattice planes, Braggs Law, reciprocal space and calculated d spacings. This led on to peak intensities (measured and calculated) and calculated diffraction patterns. We then discussed the temperature factor, thermal diffuse scattering and counting statistics. Briefly we discussed X-ray production, data recording and the fact that it is still sometimes better to record XRD data on film rather than with a counter. On Wednesday, we all got up jolly early and were in our seats for the 8.30 am kick-off! Dave Taylor described the development of the ICDD Database from the early days of the PDF (paper based, which I still find very useful) through to the PDF2 (CD-ROM). Measured 2theta values from film; recorder paper or APD's are worthless unless the instrument is calibrated. From this we discussed the Reference Intensity Ratio, and Measurement Errors. SRM1976 - the standard Corundum sample, Silver Behenate (for low angle work) and a mixed Lanthanum Hexaboride/Silver Behenate standards were all discussed, which led on to preferred orientation and the fact that sometimes (most of the time?) it is only possible to record oriented diffraction data. John Faber then described the evolution of search indexing/search match routines especially those of Hanawalt (Don) and Fink (Hugo). He then went on to talk about GOM (Goodness Of Match), and the PDF 4 search /match program and other relational databases. After tea in the afternoon we all got the opportunity to try out the next release of PCIWIN software. This is a (very) new PC based Hanawalt/Fink - Search/Match program. It is a fairly complicated software package (obviously) and worked reasonably well with the examples provided. However, as with all new software, it still had a few bugs that need to be sorted before it is released as a commercial product (which may well have been addressed by the time that you read this report). Richard C.E. Morris Forum II meeting reports13-14 th November 2003, Birkbeck College, London Thursday 13th AMThe meeting started with a brief introduction by Jeremy Cockcroft who also thanked Dave Taylor for all his hard work in organising the meeting. Unfortunately, Dave could not be at the present as his wife Ann was recovering from hospital treatment. We all wish you a speedy recovery Ann. Opening session - Non-ambient Diffraction + Amorphous Pharmaceuticals. 1. In-situ Diffraction From Materials and Macromolecules Under Microwave Irradiation - Andrew Harrison, University of Edinburgh. The design and construction of equipment to drive solid-state reactions using microwave radiation and the monitoring thereof using X-ray or neutron scattering was discussed. Andrew described how fundamental information could be obtained from in-situ studies for e.g. the direct synthesis of magnetite from microwave hydrolysis of Fe2+ and Fe3+. The original microwave source was a commercially available microwave oven, which was attacked with a hacksaw and a soldering iron! However, it was soon discovered that these units are unsuitable for sensitive heating control because they always run at full power - only the time of the irradiation can be varied. This experimentation led to the development of a purpose built instrument in which the microwaves could be "broadcast" by use of an antennae inside a high-pressure reaction bomb. Issues with thermometry, uneven heating and hotspots were also discussed as were the measurement of cell parameters including lattice expansion. Future work will include in-vivo studies of biomolecules for e.g. protein "wringing" modes. 2. Non-Ambient Laboratory Powder Diffraction Studies - Synthesis, Kinetics And Phase Transitions - John Evans University of Durham. In this presentation John described some of the laboratory experiments, which have been made possible by new developments in non-ambient powder diffraction technology including the synthesis of materials, the study of reaction kinetics and phase transitions. The equipment used was a Bruker D8 Advance diffractometer combined with a 1500 K furnace, a Cryofurnace (77 - 723 K) and a Cryostat (11 - 300K). Variable temperature powder diffraction gives lots of new information about the properties of materials for e.g. expansion rates, phase transitions, kinetics, crystallization, chemistry, order-disorder transitions. Structural phase transitions of inorganic oxides, for e.g. framework materials such as ZrW2O8, in which the unit cell is found to have a negative coefficient of thermal expansion. Following the change of width of the diffraction peaks enables
the monitoring of domain changes as a function of time. Synthesis of ZrW2O8 has also been performed in the diffractometer. 3. A Review of Methods Used to Quantify Amorphous Content in "Crystals" - Graham Buckton, The School of Pharmacy, University of London. Graham started his presentation by asking the question - "Is
amorphous material important" to which the answer is - Amorphous material is usually thermodynamically unstable, its presence is not normally intentional (e.g. it is introduced during the milling process) and it acts as sites for the absorption of water. Normally present at about the 1-2% level. How does one study / quantify it? Various techniques available;
For example amorphous lactose and amorphous raffinose Amorphous content may be viewed in two different ways; If the product starts at 100% crystalline physical manipulations such as milling will disrupt the surface and introduce an amorphous phase(s?), which will vary with time so the properties of your product are not constant and will vary from batch to batch. Thursday 13th PM – Crystallography in Materials Science4. Standardless Phase Quantification of Industrial Coatings - Susan Etok, RMCS Cranfield University. Susan described the process of plasma spraying of hydroxyapatite onto titanium substrates compared to direct, low temperature electrodeposition for use in prosthetic coatings. It is important to measure the amount of amorphous calcium phosphate in these coatings and this was done using XRD. 5. Understanding Gear Performance with X-ray Diffraction - Brian Shaw, Design Unit, University of Newcastle. Submarine Gearboxes - makes a change (sorry!) Brian described the importance of how gear design and mechanical alignment can be improved from residual stress XRD measurements. 6. Use of Intense Radiation Sources in the Study of Functional Materials - Paul Barnes, Industrial Materials Group, Department of Crystallography, Birkbeck College. Paul described how neutron and synchrotron sources are enhancing rapid time resolved observation of functional materials using such techniques as XRD. Three stories were told to enlighten us; 7. Building Your Own Furnace for HT-XRD - Gopinathan Sankar, Davy Faraday Research Laboratory, The Royal Institution of GB. This paper described some of the in situ cells that have been developed for examining phase transformations in catalytic materials. 8. Using High Temperature X-ray Diffraction with Steel / Aluminium Production: Look Where the Action is! - Stefan Melzer, Corus RD&T, Ceramics Research Centre, The Netherlands. This presentation described how production processes can be controlled and improved by following the melting and crystallisation of materials at high temperatures using X-ray diffraction. 9. Inconstant Catalysts - Steve Norval, ICI Measurements Science Group Amongst other processes, Steve described the importance of XRD in catalyst design noting amongst others the production of ethylene oxide (a major precursor of many surfactants) and the production of margarine from linoleic acid. Friday 14th November AMIndustrial Group Award Lecture: Adventures in Crystallography in the Gas Turbine Industry - Colin Small, Rolls Royce PLC, Derby. Following an introduction from Judith Shackleton in which Colin's' career in XRD at RR was described pictographically using "Haircuts Through the Ages" as it's central theme, Judith presented Colin with his BCA IG award for outstanding contribution to X-ray Analysis which was a molecular model of Diopside (CaMgSiO3). She also presented him with a model of a Supermarine Spitfire and a pair of the most sought after Vulcan Appreciation Society socks! After much applause, Colin thanked Judith and the audience and with his normal aplomb got stuck into his presentation. Oh dear, oh dear me. Colin was not up to his normal stratospheric presentational standards - no, this time he surpassed himself! His description and video footage of the Rolls Royce patented goose slicer (more of which later) will long be remembered by the traumatised audience (which included Colin's parents, wife and children).  Colin went on to describe the Rolls Royce Trent 900 gas turbine engine, which will eventually be fitted onto the Airbus A380 airliner, which will ferry us all about the planet during our summer hols. (Bye-the-way this engine has a by-pass ratio of 8.1:1 and develops 70,000 lbs of thrust). As aeroplanes fly through the air they ingest any manner of debris; from hailstones through to the major constituent of your Christmas dinner. So, not surprisingly, the testing procedures that these engines have to endure are extremely rigorous. Some of these Colin described, including the hail gun, during which a zillion tons of ice per minute are "shot" at a running engine and the bird injection test, for which there are three standards - the small bird (~2 ½ lb chicken) the medium bird and the large bird, (the afore mentioned goose) of about 8 lbs. Colin pointed out the importance of defrosting the feathery projectiles before shooting them into the engines ! Colin went on to describe the importance of determining the structural integrity of the turbine blades of the engine and how this is monitored using XRD. The turbine blade is also full of small holes to allow the passage of 70 tons/min of air through the engine and in dusty environments (e.g. deserts) these holes can clog up with dust which melts (to form Diopside which was identified using XRD) and as the blades are operating at some temperature above their melting point this is not a good thing! Next was the problem of volcanoes - or more specifically the problems encountered when an aircraft flies through the dust plume of an eruption. The dust particles from an eruption are extremely abrasive and it has been one of Colin's major tasks over the last few years to understand exactly what goes on inside a gas turbine engine when it swallows umpteen tons of vapourized pumice. The fan blades of the engine - the ones at the front (and do the bird slicing) - are composed of three sheets of titanium and are hollow. The way in which the crystalline texture of these blades is effected during their manufacture is crucial. Colin went on to describe his use of pole figures, Euler space and orientation distribution functions in his quest for a numerical description of texture of the fan blades that engineers could understand. Colin concluded his lecture by describing how the turbine rotor shaft is joined using an enormous inertia welding kit. The only way to examine the resulting joint is by neutron diffraction and this was carried out at the ISIS facility at RAL (must have been difficult getting the samples in and out of the hire car!). Another round of applause followed - Colin, X-ray diffraction lectures will never be the same again! Friday 14th AM Industrial Applications of XRD1. Microstructural Characteristics of Advanced Materials Using Electron Backscattered Diffraction (EBSD) - Phil Holdway (and H.S. Ubhi) QinetiQ Ltd, Farnborough, Hampshire. Phil briefly described the theory of EBSD before moving on to some applications. First of all you need an SEM with the sample tilted to around 70º and successful analysis relies on having strain free surfaces and Kikuchi patterns are produced from Bragg diffraction peaks of back scattered electrons from the sample which have an interaction depth on the sample of ~50 nm. Data collection is made by scanning over a grid and can be either manual or automatic. For example shape memory alloys - Ti/Ni - the SEM image is used to select a particle for analysis then EDS is used for elemental analysis and EBSD to determine the crystalline properties of the particle - in this way it is possible to obtain complete identification of small particles within an alloy with no need for TEM or XRD. Phil then went on to discuss the analysis of ZrH and ZrH2 formation on the surface of Zircalloy. And the analysis of grain structure in laser deposited W, a process that enables the formation of complicated shapes that could not be manufactured using conventional machining techniques. (It is much less wasteful to build a structure up rather than start of with a large lump and end up with a pile of swarf). Phil went on to say that although EBSD ids a powerful tool and can make up to 50 measurements a second, only a very small area is examined when compared with conventional XRD. 2. XRD and Reflectivity Measurements in the Glass Industry - Mark Farnworth, Pilkington plc. Mark described how the techniques of XRPD, GAXRD, pole figures and X-ray Reflectivity measurements can be used to examine samples from all stages of glass manufacture, from the crystalline raw materials to the amorphous final product. GAXRD is used to examine thin coatings on the glass surfacrce for e.g. hydrophobic coatings, which disperse water. Refractory materials are examined to determine how much non-crystalline material is present and the amounts of quartz, cristobalite and tridimite. Also, multi-layer stack coatings are examined e.g. Ti ZrO2 Ag Si. Texture maps can be produced which show the degree of texture in the silver layer of the coatings and the thickness, density, top and bottom roughness of each individual layer can be measured. 3. Applications of XRD in the Imaging Industry - David Beveridge, Ilford Ltd. With the advent of digital imaging technology the decline in sales of silver halide based film emulsions has been swift. So members of the imaging industry have had to adapt just as swiftly and this has had an effect of the type of samples that the X-ray crystallographer can now be expected to examine. David explained that, historically, most of his samples were silver halide film surfaces and included the identification of the composition of processing solutions, now the majority of his samples are from printer-pigmented inks. Pharmaceutical Parallel Sessions – Thursday PM & Friday AMOver the course of two days three parallel sessions were held covering non-ambient PXRD applications, polymorphism case studies and the analysis of amorphous materials in a series of nine 30-minute lectures. The non-ambient session was started with an excellent introduction to RELATIVE HUMIDITY CONTROLLED X-RAY DIFFRACTION by Brett Cooper, (MSD), explaining what relative humidity is and how its variation can impact on pharmaceutical ingredients. He described the latest computer controlled system and how it is now possible to mimic the complementary technique of Dynamic Vapour Sorption (DVS). An example of one of these new computer controlled systems, the Bruker/Ansycos Hot Humidity Controlled system giving the ability to stress samples with combinations of high temperature and high relative humidity. Terry Threlfall (University of Southampton) spoke on STRUCTURAL SIMILARITY, DISSIMILARITY AND REPRESENTATION using alklimetal tartars, frusemide and sulponamides as examples to reveal unexpected relationships between structures. The use of high pressure was described by Simon Parsons (University of Edinburgh), POLYMORPHISM INDUCED BY HIGH PRESSURE, pushing out the boundaries of polymorph hunting. He described the experimental conditions using a diamond anvil cell, CCD diffractometer and 'fairly modest' pressures (1-15kbar) to search for new forms of formamide, pryridine and glycine. The high-pressure system was also used to study the formation of co-crystals. Chris Frampton, (Bruker-Nonius) POLYMORPHIC DRUGS SCIENCE, FASHION OR VALUABLE PRODUCTS gave a highly interesting and entertaining talk on the importance of establishing the most stable form of a compound and acquiring the intellectual property rights. He used the examples of Ranitidine, Ritonavir and Paroxetine to illustrate his talk. The importance of finding the most stable form was emphasised by Dan Cowell, (Pharmorphix Ltd.), POLYMORPHISM STUDIES IN THE PHARMACEUTICAL INDUSTRY. Dan stressed that high throughput screening was only part of the answer and that better focused screening at medium and low throughput could lead to the most stable form with greater understanding. THERMAL TRANSFORMATIONS-CASE STUDIES by Ron Roberts (AstraZeneca) showed examples of structural changes during heating and cooling using hot-stage X-ray diffraction. Examples of lattice expansion and calculation of thermal expansion coefficients were also shown. Stephan Watts, STRUCTURAL CHARACTERISATICS OF THE AMPRPHOUS PHASE: A COMPUTER MODELLING APPROACH, (Pfizer Institute for Materials Sciences, University of Cambridge) talked about a new approach to the understanding of amorphous materials using molecular dynamic simulation techniques. The final two lectures concentrated on novel techniques for the quantification of the amount of the amorphous phase in materials. Paul Royall, (Kings College, London), APPLICATION OF DYNAMIC MECHANICAL ANALYSIS (DMA) IN THE CHARACTERISATION OF AMORPHOUS POWDER spoke of the application of DMA to powders as opposed to solid samples. Mixtures of amorphous and crystalline lactose were used to establish a linear relationship between the amorphous content and the DMA relaxation strength. The results from a sample of micronised crystalline lactose were more complex and further work is ongoing to understand these results. Susan Barker, (University of East Anglia), THE USE OF THERMALLY STIMULATED CURRENT SPECTROSCOPY (TSC) IN THE STUDY OF AMORPHOUS AND POLYMORPHIC MATERIALS, described TSC as an electrical technique whereby dipolar movement and relaxation is measured under the influence of varying thermal and electrical stresses. The various modes of operation of TSC were described in relationship to caffeine and indomethacin. In all, a very interesting session for all those interested in the characterisation of pharmaceutical solids. Friday 14th pm Joint SessionThe final session of the forum was devoted to the theme of X-ray Diffraction: Past, Present, and Future. With the meeting being held in the Clore management centre in Torrington Square, Birkbeck College, then it was highly appropriate that Alan Mackay should open the session with a lecture on the past. – the old buildings of the Crystallography Department as founded by J.D.Bernal used to stand on the adjacent site. Amongst the many photos of old equipment, he showed a picture of Bernal's X-ray rotation camera – and then contrasted it with the "big science" now done at the ESRF. Probably though the biggest changes have been in computing as shown by the photo of an early computer at Birkbeck college from the 1950s laboratory of Donald Booth. The second talk was by Judith Shackleton on present X-ray instrumentation, a difficult talk to give without advertising the advantages of one manufacture over an another. After working her way through the maze of primary and secondary optics, monochromators and mirrors, area and solid-state detectors, she arrived at the "Portable Stress Diffractometer" – a most remarkable piece of kit capable of measuring stresses in very large objects indeed. One wondered what the response would be at Birkbeck College to its lack of radiation shielding! The Industrial Group committee decided that the final talk of the forum should be an Alun Bowen lecture given the importance of future instrumentation for industrial crystallography. The talk on the new UK synchrotron source was given appropriately by Alexander Korsunsky, who described the features of the beamline JEEP proposed for DIAMOND. The talk ended with an aerial photo of the DIAMOND site showing that construction was now seriously underway and the "future" lay just ahead.
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Industrial Group of the BCA