Elemental and structural analysis

In many production or R&D settings, X-rays can be used to characterize materials and samples. X-ray analysis is exceptionally suitable to analyze structures and elements at the atomic level. X-ray fluorescence (XRF) and X-ray diffraction (XRD) are two out of a few main techniques how X-rays can be used to help characterize your sample.

What do you analyze with X-ray fluorescence?

With the help of XRF, we analyze the elements that are present in materials. Take as an example iron. Nowadays, there are hundreds of different types of steel. Normal iron will get rusty in time but, when you add 18% chrome, and 8% nickel, you will get stainless steel. But how can you determine the right composition of steel -18% chrome, 8% nickel- and ensure consistency when it is liquid hot steel in a steelworks?

Easy, you pick a sample, let it cool down, and send it to an XRF analyzer which can easily measure the composition. When this composition matches the specification, the liquid steel can be poured, and unnecessary heating is avoided. Saving costs on power consumption makes the production process more cost-effective and spares the environment. You can use XRF not only for the analysis of steel but also for many other materials like:

  • air filters
  • plastics,
  • petrochemicals,
  • building materials,
  • chips in electronics,
  • minerals,
  • metals

and many, many more.

Why do we analyze materials using X-ray diffraction?

XRD enables us to detect the three-dimensional arrangement of the atoms in a solid crystal. Take for example carbon. Both diamonds and graphite are entirely made of carbon but they have very different properties. Graphite is rather soft, can be used as a lubricant, and conducts electricity. Diamond, on the contrary, is the hardest material on earth and does not conduct electricity. How can these different properties be explained? Analysis by X-ray diffraction gives the answer. If we put the sample in an X-ray diffractometer and irradiate it with X-rays, we can detect the reflected radiation. Dedicated software can reveal the three-dimensional arrangement of the atoms in both materials. Carbon atoms in the soft graphite form layers with only weak bonds to the neighboring layers. Carbon atoms in diamonds, however, form strong bonds to four neighboring atoms and are closely packed in all three dimensions. XRD can be used for the structural analysis of many different materials like:

  • Batteries: how does the structure of anode and cathode change during a charge/discharge cycle?
  • Metal organic frameworks: has my target MOF has been synthesized correctly?
  • 3D printing: what are the characteristics of my raw material affecting the hardness, strength and fatigue life of my final component?
  • Pharmaceuticals: does my medication contain the prescribed substance?
  • Building materials: for example, does the cement consist of the specified compounds?
  • Minerals: what minerals are mined?
  • Metals: is the metal stress free or is there a chance of a fracture by fatigue?

and many, many more.

 

Posted by: Malvern Panalytical – www,materials-talks.com

5 high-quality CRMs to test various Aluminum industrial applications

Aluminum is known for being one of the lightest engineering metals that has a higher strength-to-weight ratio than steel. Pure aluminum is also a soft and flexible metal with high electrical/thermal conductivity and corrosion-resistant properties. To provide better strength to aluminum for more demanding applications, it is commonly alloyed with other metals, such as copper, zinc, magnesium, silicon, manganese, and/or lithium.

Aluminum alloy 6063 (AA6063) is a medium strength alloy, commonly used in extrusion applications. Grade 6063 has good mechanical properties and is also heat treatable and weldable. There are a variety of popular applications for this metal, including architectural applications, window frames, doors, roofs, sign frames, shop fittings, and irrigation tubing. The grade specs for AA6063 allow for the following compositional ranges: 0.2-0.6% Si, 0-0.35% Fe, 0.45-0.9% Mg, 0.1% max Cr, 0-0.1% for Cu, Mn, Ti and Zn. Our new MBH-AL6063-20 standard falls well within these ranges with Si=0.46%, Fe=0.156%, Mg=0.481%, Cr=0.0088%, and under 0.1% for Cu, Mn, Ti, and Zn. It is supplied in a 50mm x25mm disk for OES application, or as chips for easy digestion for liquid analysis techniques.

The other four new alloys have all been made specifically doped with measurable concentrations of typical trace/tramp elements. This allows them to be used to verify low-level analysis of these elements. They are also provided as either a disk with 65mm diam (25mm thick) or as chips for easy dissolution. This larger size allows for more sparks per polish, and less re-surfacing for OES techniques. The manufacturing process for these alloys also results in highly homogenous bars, so the composition will be very consistent throughout the sample.

AdobeStock_183250561Aluminum grade 6061 (AA6061) is the most commonly available aluminum alloy on the market. This grade is often used in applications where high strength is required, and the typical applications for AA6061 are general purpose or manufacturing needs including truck and marine components, furniture, pipelines, heavy-duty structures, railroad cars, and high-pressure applications. Our new MBH-AL6061-19 reference material meets the grade criteria elements with Mg=0.896%, Si=0.71%, Cu=0.247%, and Cr=0.254%. The COA also lists certified concentrations for 13 other elements, including Bi, Cd, Pb, and Sb.

Alloy 356.2 (AA356.2) is another high-strength aluminum alloy commonly used in aircraft applications. AA356.2 can also be used as a substitute for aluminum alloy 6061 if needed. Typically, this grade is used in pump housings, impellers, high-velocity blowers, and structural castings where high strength is required. Our new MBH-AL356.2-19 meets the grade requirements, with Fe=0.22%, Mg=0.39%, Si=6.9%, and Ti=0.185%. The COA for this alloy also lists certified values for an additional 16 elements including Bi, Ca, Cd, Co, Cr, Ga, and Sb.

Aluminum alloy 3104 (AA3104) is the most commonly used alloy for aluminum can bodies, due to its ability to be easily formed, and yet maintain its strength in the finished form. Our new MBH-AL3104-20 standard meets all grade requirements, with Cu=0.197%, Mg=1.10%, Mn=1.07%, and Fe=0.315%. The COA also lists certified concentration values for an additional 15 elements, including Be, Bi, Cd, Pb, Sb, Sr, and Ti.

Finally, alloy 5182 (AA5182) is a lightweight and malleable metal that has been in use for centuries. Common applications for this aluminum alloy include automobile applications (body panels and reinforcement members), aluminum can tops, brackets, and packaging products such as containers. Its composition includes magnesium and manganese as minor elements, ranging from 4-5% Mg and 0.2-0.5% Mn. Our new MBH-AL5182-20 CRM hits the mark with Mg=4.01% and Mn=0.39%. This COA also lists many trace elements, with a total of 19 total certified concentrations, for the alloying elements as well as trace elements such as Be, Bi, Cd, and Sb to name a few.

 

Written by: Kim Halkiotis, Posted by LGC Industrial (www.armi.com)

Elemental analysis : The cure-all solution to more efficient base metal mining

Have you met Doctor Copper? With a Ph.D. in economics, he’s famous for his ability to predict the health of the global economy! If this sounds too good to be true, that’s because Doctor Copper isn’t really a person – he’s a concept. The idea is that, because copper is so fundamental to a range of global industries, its price indicates overall economic well-being.

Copper, zinc, nickel, and lead are the base metals that build our world. While they don’t quite have the glamour of precious metals, like gold, silver, and platinum, base metals underpin our global economy. They’re utilized in a range of industries, including telecommunications, transport, and construction. With such a fundamental role in our day-to-day lives and the health of our markets, we must mine these metals in the most time-, cost-, and energy-efficient way possible.

The growing need for cleaner, greener mining

In recent years, there has been increasing global attention on the environmental impact of mining. Many mining companies are on ongoing missions to improve their operational efficiencies. A key focus of these efforts is elemental analysis, which allows operators to better match their use of resources, such as water, energy, and chemicals, to the ores they process.

In many stages during mining processing, such as electrowinning, conventional elemental analysis remains time-consuming, inefficient, and costly. Why? Because most sites still rely on liquid analysis with titration. Measured every four hours, this analysis generates limited, user-dependent data points that make process control inefficient. The infrequency of the monitoring also means that the electrolysis bath lacks stability. And all this means lost time, energy, and money.

Meeting the demand for more efficient elemental analysis

But we have the solution! The Epsilon XFlow is an online analyzer that provides insights into hydrometallurgy, leaching, electroplating, and wastewater processes. Using energy-dispersive X-ray fluorescence (ED-XRF) technology, this system produces continuous, real-time elemental analysis in liquid processes. In this way, it lets you change process conditions immediately to ensure efficient production and optimum product quality.

And that’s not all. Thanks to the latest flowcell technology, Epsilon XFlow can also produce highly repeatable results, both short- and long-term. This means that accuracy levels remain high, even when carrying out fast, simultaneous multi-element analysis. Plus, the system has a proven user interface for easy operation and maintenance, remote service and support options, and is chemically resistant to a wide range of liquids. This is essential when using the kinds of high-acidity liquids needed in base metal extraction processes.

Industry-leading solutions for elemental analysis

The Epsilon XFlow is a complete solution for making liquid analysis in mining safer, faster, and more cost-efficient. But we don’t stop there. At Malvern Panalytical, we offer a range of other analytical solutions for base metals mining, including our ASD QualitySpec 7000 Process Spectrometer. This system is designed for the continuous measurement of solids, powders, and blended materials – with the potential to save mining companies hundreds of thousands of dollars. Malvern Panalytical is helping to lead the way to a cleaner and more sustainable future for base metal production. And with solutions so smart, not even Doctor Copper could have thought of them!

 

Written by: Uwe Konig , Posted by: Malvern Panalytical (www.materials-talks.com)

New Copper alloy CRMs: verifying versatile properties

Copper is a versatile metal used for a wide variety of applications. The alloying elements that are combined in Cu provide properties, such as strength, electrical conductivity/resistivity, ductility, luster, and even anti-microbial qualities, that are very desirable for the end user. Verification of the composition of the final alloys is critical to ensuring the material will be fit for use.

Our brand new and long-awaited CRM IARM-Cu844-18 can be used for instrument calibration and/or compositional verification of copper alloy CDA 844 (UNS C84400). CDA 844 is one of the most widely used alloys in the leaded semi-red brass family. It is found in several consumer products, including musical instruments, HVAC equipment, electrical equipment, ornamental fixtures and even valves and building hardware. The versatility of this alloy is boosted by its reasonable cost as well as excellent machining and casting properties, which are achieved by the proper combination of alloying elements Zn, Pb, and Sn. Our semi-leaded red brass, IARM-Cu844-18, falls within grade spec for these critical elements, and its certificate of analysis (CoA) reports certified values for 14 additional elements: Ag, Al, As, Bi, Cd, Co, Cr, Cu, Fe, Ni, P, S, Sb, and Se. Reference values are also given for four more elements.

iStock-901858684

 

CDA 836 (UNS C83600), also known as 85 metal (85% Cu, 5% each Pb, Sn and Zn), is a leaded red brass copper alloy that is the most commonly used alloy in this brass family. CDA 836 has good resistance to corrosion, wear and fatigue and also shows good electrical/thermal conductivity and moderate strength. Additionally, it has good machinability and high cast yield. This alloy is typically used for plumbing or marine applications, such as: valves, flanges, pipe/marine fittings, plumbing goods, pump castings, water pump impellers/housings, ornamental fixtures, and small gears. Our CRM IARM-Cu836-18 replaces our popular CRM IARM-86D. The CoA for Cu836-18 contains certified values for the four alloying elements of CDA 836 plus 12 additional trace elements, including Ag, As, Bi, Cd, Co, Fe, Nb, Ni, P, S, Sb, and Se. It is appropriate to use for instrument calibration and/or compositional verification.

Beryllium copper CDA 172 (UNS C17200) alloys have strength and hardness properties similar to steel, while still providing excellent corrosion resistance and electrical conductivity. CDA 172 is harder than most other copper alloys and is commonly used in electrical connectors, current-carrying springs, fasteners, welding equipment, bearings, tools, and corrosion-resistant components. Our new IARM-Cu172-19 CRM replaces our popular CRM IARM-Cu172-18, and the CoA reports certified values for 14 elements, including Ag, Al, Be, Co, Cr, Fe, Mg, Mn, Ni, P, S, Sb, Si, and Sn. Reference values are also provided for seven additional elements.

Written by: Kim Halkiotis  – Posted by: ARMI MBH – LGC (www.armi.com)

Super powering solutions for more efficient aluminum smelting

Extraordinary strength, astonishing flexibility, incredible resilience, and striking good looks. No, we’re not talking about your favorite comic-book hero. We’re talking about another everyday champion: aluminum!

Aluminum and its alloys are widely used in a vast range of industries and for a number of applications. The application example is ranging from household appliances to power lines, and from car parts to aerospace components. Furthermore, demand is increasing globally – a trend we can expect to continue in the years to come. For this reason, it’s more important than ever to make aluminum smelting more efficient and sustainable.

The true cost of inefficiency

In recent years, as bauxite quality has started to decline, prices for raw materials have started to rise. Consequently, there is significant increased interest in sustainability topic. Since then, the mining industry has been working hard to make its processes more efficient and sustainable. And in few places is this more critical than in aluminum smelting.

With aluminum extraction being such an energy-intensive process, attaining the highest yield possible from your alumina source is critical to reducing your costs and lowering your environmental impact. Quality control and analytics tools in smelting required careful monitoring, regular calibration, and technical maintenance. Therefore, many have been searching for better ways to drive time, cost, and energy savings.

Big problems, small solutions

With Malvern Panalytical’s innovative X-ray diffraction (XRD) solutions, we need look no further. Our XRD tools can be used across the aluminum production chain to drive safer and more efficient aluminum smelting process – from ore grading, to analyzing refined alumina, to monitoring crystallinity. Especially in the area of electrolytic bath (potflux) analysis we have made an especially exciting innovation.

Our new XRD technique – combining AERIS benchtop XRD with Rietveld quantification – offers a highly efficient solution for potflux analysis. From preparing the test samples to reporting the results, this tool is a one-stop-shop for measuring and optimizing smelters. And the best part? It’s fully automatable and standardless. Meaning, you can get fast and reliable compositions for a range of materials with minimal user input. Simply load a sample – or let the tool do it for you – enter the sample name and start the measurement. And that’s it – you’ll have your results in as little as 24 seconds!

Smelting solutions are just the start…

By combining XRD technology with Rietveld analysis, we are blazing a path for safer, more user-friendly analysis and more efficient aluminum smelting. But we don’t stop there. Malvern Panalytical offers a range of solutions to optimize your processes throughout the aluminum production chain. For example, our X-ray fluorescence (XRF) tools, such as our Epsilon 4 mining and minerals edition, are effective to ensure that waste composition is within environmental limits, as well as checking for toxicity or impurities.

With these solutions and more, Malvern Panalytical drives the shift towards a more sustainable future for aluminum production. And if you ask us, these industry changes are nothing short of heroic…

Written by: Uwe Konig, Posted by: Malvern Panalytical (www.materials-talks.com)

Ask an expert! – Getting the best out of Omnian using an ED spectrometer

X-ray fluorescence (XRF) analysis is a robust analytical technique that provides both qualitative (which elements) and quantitative (how much of that element) information about a sample. The combination of this ‘which?’ and ‘how much?’ makes semi-quantitative analysis possible.

XRF quantitative analysis

In qualitative analysis, peak search and peak match are used to discover which elements are present in the sample. Peak search finds the peaks, and peak match determines the associated elements by referring to a database.

The usual procedure of quantitative analysis in XRF is to calibrate the spectrometer by measuring reference materials. The calibration determines the relationship between the concentrations of specific chemical elements and the intensity of the fluorescent lines of those elements. You can determine unknown concentrations of calibrated elements once this relationship is known. The intensities of the elements with unknown concentrations are measured, with the corresponding concentration being determined from the calibration. A typical limitation of an accurate XRF quantitative analysis is that unknown samples should be prepared in the same way as standards used for calibration, and in many cases to be of the same nature.

What is semi-quantitative analysis

A semi-quantitative analysis in XRF usually is a combination of both, qualitative and quantitative analyses. The semi-quantitative analysis determines the presence of all measurable elements. That is in contrast with “classic” quantitative analysis, which is calibrated only for specific elements present in the standards. Usually, a semi-quantitative analysis has one “universal” calibration that can be applied to specimens of samples of different origins. It can also make a relatively good estimate of concentrations of elements and compounds which weren’t even present in the original calibration.

A semi-quantitative analysis is basically the same for Energy Dispersive (ED) XRF and Wavelength Dispersive (WD) XRF. Both WD and EDXRF are used to identify and determine the concentrations of elements present in solid, powder and liquid samples. The exact same mathematical methods can be used to calculate the composition of samples. The only difference is that in EDXRF the area of a peak gives the intensity, while in WDXRF the height of a peak gives the intensity.

Omnian Standardless analysis

Omnian is a Malvern Panalytical XRF application package that can provide (semi-)quantitative* chemical composition analysis of virtually any sample that one can place in an XRF spectrometer. Usually, we use it in situations where specific calibration standards are not available. Or we use it when samples are out-of-scope of normal laboratory routines.

When faced with non-routine samples or materials for which there are no certified reference materials, the software provides insight into the elemental composition. Its advanced fundamental parameters algorithm automatically deals with the analytical challenges posed by samples of widely differing types.

Get the best out of your Omnian analysis

Omnian is an “open” application package and users can make some changes to the default parameters to improve precision, accuracy, or Lower Limits of Detection in their measurements. It is a powerful tool but, are you making the most of it? If you want to make sure you know how to get proper analysis results out of it or have questions regarding your Omnian analysis, then join the next ‘Ask an Expert!’ webinar titled ‘Getting the best out of Omnian using an ED spectrometer’.

 

Written by: Vincent Kip, Posted by: Malvern Panalytical (www.materials-talks.com)

X-ray tubes for more than half a century

Did you know that Malvern Panalytical is the only supplier of analytical (X-ray) instrumentation that also develops and produces its own X-ray tubes?

The X-ray tube factory resides in Eindhoven, the Netherlands. The modern clean rooms and logical flow layout facilitate new technology innovation, efficient production, and excellent quality control. After the move from the old facility to the new factory in August 2011, all our technical processes have been optimized to the new building, so as to optimally exploit its potential and further improve our X-ray tube quality.

All products are benefitting from the optimized manufacturing conditions. In particular the latest and most innovative ones: SST-mAX, Empyrean Tube, and Epsilon Tube. At the time, the X-ray tube factory was the latest milestone in Malvern Panalytical’s long history of X-ray tube innovation.

Assemblers and engineers working in the Malvern Panalytical X-ray tube factory

A bit of history

After World War II, Philips developed the X-ray diffraction (XRD) glass tube which today is still a world standard. After that came the renowned 100 kV XRF side window tube for sequential spectrometry and the end window tube for simultaneous spectrometry.

During the early seventies, Philips decided to separate their analytical and medical tube activities and built the first and only X-ray tube factory in the world dedicated to XRD and XRF tubes. This created a 100% focus on analytical tube innovation and manufacturing and led to the development of the first ceramic analytical tube, the XRF Target Transmission Tube. In the early nineties, the revolutionary ceramic XRD-C and SST were developed.

Glass X-ray tube in the making

These two successful tubes then formed the basis for further groundbreaking innovations: thinner beryllium windows, higher power, better spectral purity, enhanced stability, and longer life. This has led to today’s Empyrean Tube and SST-mAX CHI-BLUE, incorporating more than 50 years of X-ray tube experience and know-how.

X-ray tube innovation is never at an end. Malvern Panalytical continues to be dedicated to new technology development and the creation of new user benefits. The X-ray tube factory provides the perfect basis for many new developments in years to come.

 

Posted by: Malvern Panaltyical (www.materials-talks.com)

How real-time ore monitoring can save hundreds of thousands of dollars

In an increasingly volatile and unpredictable world, we all want to make cost-efficient choices. And often, the materials we choose can play a big part in these efforts. Whether it’s a car or a pair of shoes, products made with high-quality materials can help you save on waste, maintenance, and replacement costs in the long run.

Something similar could be said for mining – where rising process costs are also making cost control increasingly important. Just as in other areas, high-quality materials can help: a key way to drive cost-efficiency in mining is by maximizing the recovery of high-quality ore. This can reduce waste from lower-quality ore, improve process efficiency, and enable higher-quality end-products – all factors that boost overall profitability.

Acting quickly is key to cost-efficiency

The secret to these high levels of high-quality ore recovery? Fast mineralogical analysis – especially when it’s in real-time during processing! Real-time measurements allow operators to react quickly to the quality and composition of materials as they’re processed. This can remove lower-quality ore from the process as soon as possible, remove the need for time-consuming sampling and laboratory analysis, and minimize operational downtime.

NIR: A rapid real-time analysis technique

Near-infrared spectroscopy (NIR) is a rapid, reliable solution for this real-time analysis. How does it work? Well, using the near-infrared region of the electromagnetic spectrum, NIR measures the light scattered off and through a sample. In this way, it creates a ‘fingerprint’ of the ore that reveals its properties and mineralogical composition.

NIR provides non-contact, above-the-conveyor-belt measurements of materials as they’re processed on the belt. This means it delivers instant results, enabling quick decision-making that can reduce waste, save time, and improve quality. And, unlike some analytical techniques, NIR is non-destructive and requires little to no sample preparation.

QualitySpec® 7000: Improved knowledge, increased control

The best news? At Malvern Panalytical, our QualitySpec® 7000 NIR spectrometer is setting a new standard for non-contact NIR analysis. At the core of the QualitySpec 7000 are a simple, safe quartz-halogen light source and a highly sensitive detector array. The spectrometer is calibrated with the help of chemometric modeling techniques from ASD’s SummitCAL Solutions Team. This allows it to be combined with a process control system to transform its data into actionable information.

The result is a powerful system for real-time, closed-loop process and quality control, which is particularly ideal for continuous measurement of solids and blended materials. By providing multiple measurements from a single point, the QualitySpec 7000 yields more information, more quickly – facilitating extra-fast real-time process decisions. Even better: it’s ultra-easy to maintain.

Significant cost savings await…

And the results you can expect using the QualitySpec 7000? Well, by allowing you to analyze and sort your incoming ores in real-time, this instrument could reduce your production downtime and decrease your acid consumption during heap leaching – enough to save your mine $250,000 per year! With real-time process analysis, cost-efficient mining really is simple – as simple as buying a high-quality pair of shoes…

 

Written by: Uwe König., Posted by: Malvern Panalytical (www.materials-talks.com)

Gain Value with Direct Insight into Your Production Process

A Quebec Mining Review Article

Increasing competitive pressure and more stringent regulations in the mining industry drive the need for more efficient processes. Real-time monitoring provides fast and accurate control of essential parameters. It saves time, prevents costly waste, and ensures adherence to tight product specifications.

An interesting article regarding online elemental monitoring was published last month in the Quebec Mining Review magazine.

The text describes how real-time monitoring with an online X-ray fluorescence (XRF) analyzer such as the Epsilon Xflow helps to:

  • Control electrowinning process to reduce energy costs
  • Monitor and control solvent extraction processes
  • Check mine wastewater compositions
The Epsilon Xflow, real-time liquid elemental analyzer.

Control electrowinning process to reduce energy costs

Power consumption is the main cost factor of the electrolysis plant. Optimal control and insights in the process can prevent scenarios where the concentration of the analyte is too low or too high. The processes are then more efficient, and the improved stability increases throughput and margins.

Monitor and control solvent extraction processes

Using online elemental analysis to monitor leach solution enables operators to switch between several streams of injection and extraction wells to ensure an optimal composition for further downstream processing. It allows to control and steer acid consumption resulting in a constant metal in-flux for further solvent extraction (SX) involving minimal energy consumption and processing costs.

Check mine wastewater compositions

Real-time monitoring of hazardous elements in wastewater treatment drastically reduces the cost for reagent each year and avoids high penalties for non-compliance with environmental norms. By moving to online elemental monitoring without human intervention, companies can increase profitability by optimizing costs for labor, reagents and avoid paying penalties.

Added-value of the Epsilon XFlow.

In short, an online analyzer that ensures high accuracy and excellent repeatability such as the Xflow allows to meet tight regulatory requirements and optimize plant throughput.

About Quebec Mining Review Magazine

The Quebec Mining Review magazine is a yearly publication that promotes mineral exploration and development through the province of Quebec, in Canada. The latest mining products and technologies are among the topics covered in this bilingual publication.

 

Written by: Geneviève Labrecque, Posted by: Malvern Panalytical (www.materials-talks.com)

The importance of crystallography in our daily lives

X-ray diffractometers are the main instruments used for studying the crystallographic properties of matter. In this blog, we will give a few examples of the importance of crystallography in our daily lives.

Many substances found in nature, are crystalline. Crystals that appear in nature, as a result of volcanic activity, are formed under high pressure or crystallized from water.

Photo by Alexander Van Driessche – CC BY 3.0, Ref 23231964

Here, you see beautiful gypsum crystals that grew during thousands of years deep under the ground. They were found a few years ago, by accident, during mining activities in Naica Mexico. These crystals are extraordinarily large; they are meters long. Note the small human figure at the bottom right of the picture.

In most cases, however, the crystallites found in nature are much smaller in size. Most rocks, soils, and sands, consist of small submillimeter particles such as iron-containing rocks.

If you’d make a cross-section of a rock fragment in preparation for the optical microscope, you’d see the small crystallographic domains in the rocks. The crystallographic properties of such rocks can be investigated with an X-ray diffractometer (XRD) such as the Empyrean multipurpose X-ray diffractometer. The Empyrean is meant for the analysis of powders, thin films, nanomaterials, and solid objects.

A single crystal deflects X-rays into beautiful diffraction patterns. Bragg’s law determines at which angle a single crystal will give a diffraction signal. Also, polycrystalline materials or powders give diffraction patterns. Of the many small crystallites contained in the powder, only the ones with the right orientation will provide strong diffraction signals. Because the diffraction signal will come from multiple crystallites, the powder pattern can also be used to determine the constitution of mixtures.

The red trace that you see here is a diffractogram. It consists of many peaks recorded as a function of the diffraction angle. From the angular position of the peaks the different components of a mixture, also called the phases in the mixture, can be determined. From the relative intensity of the peaks, the relative abundance of the phases can be computed. A powder pattern is like a unique fingerprint of the material; such a diffractogram can also be obtained from solid objects such as rocks and metals. These objects consist internally out of many small crystallites and produce their own unique powder patterns. Powder diffractograms can be recorded for many of the substances that we find in the world around us. These materials determine the quality of our daily lives. Let’s have a look at the importance of understanding the crystallography of powders and other crystalline mixtures.

Cement, a boring material?

Cement is the main construction material for the buildings in which we live, since Roman times. Did you know that the workability, the setting time, and the final strength of concrete, are determined by the crystallographic properties of cement? To be more precise, the quality of the buildings we create is determined by the crystallographic phase changes during cement hardening – a process still not fully understood by today’s scientists!

Cement is made by heating limestone and other raw materials in the long rotary oven called a kiln. In the kiln, the substances undergo crystallographic changes at temperatures up to 1,400 degrees Celsius yielding a material called clinker, which is ground afterward and mixed with other constituents in order to create cement. The making of cement results in significant emission of carbon dioxide, CO2, one of the gases responsible for global warming. For each kilogram of cement, almost one kilogram of CO2 is produced, creating about 5 percent of the CO2 emissions from human activities. It is the second source of CO2 emission after power generation.

Of the total CO2 emission in the cement production process, the majority (60%) stems from limestone calcination, 30% comes from the fuel needed to heat the kiln. The final 10% is needed for grinding of the clinker, transport of the material through the plants, and so on. Attempts to reduce CO2 emission focus on two aspects:

  • First make cement with less clinker. Industrial byproducts such as fly ash from power plants or slags from iron producing blast furnaces are used for this. These materials also have a cementitious effect.
  • Secondly alternative fuels can be used for heating the kiln such as plastic waste, animal carcasses, or used car tires, but these also influence cement properties.

The understanding of the crystallographic properties of the cement is essential for producing cement with low CO2 emissions.

Optimizing iron ore in mining

Another important material in our daily lives is iron. The starting point for all iron is the ore which is dug from the ground in mines. The quality of the ore in a mine is never constant. It was determined millions of years ago when the rocks were formed. The classical and simple way for determining the quality of the ore is by visual inspection: compare the color of the unknown with a reference set. From such a visual inspection different parts of the ore body can be classified as low grade or high grade.

By determining the crystallography, however, a much finer classification of the ore body can be made. Using this approach allows one to much better sort the mined materials into different grades and mix them to create an intermediate that is much more constant in quality; it increases the profitability of the mining activities as less waste is created and it reduces the damage to the environment.

Let’s talk about stress

When you were in an airplane traveling, did you ever wonder why the windows in the plane are oval and not rectangular in shape? Airplanes and other machinery are subject to cyclic loads during operations like takeoff and landing. After many repeated loads cracks can form at the surface which can suddenly propagate through the whole assembly causing failure: the so-called metal fatigue. Metal fatigue was not fully understood when the first commercial jet airplanes were built. The de Havilland Comet was an example of such a jet airplane that was built in the 50s. After a successful introduction of the airplane, two of these planes crashed after more than one year of successful operation, several midair catastrophic accidents happened in a short period of time. All planes were grounded, and the investigation started.

The repeated loads on the airplane’s body were simulated by placing one of the remaining airplanes in a water tank – which was repeatedly pressurized and depressurized. After more than three thousand cycles the plane suddenly burst open. The investigation showed that a fatigue crack had occurred at the corner of a rectangular window. From the simulated stresses in the window frame, one could see that these stresses are much higher in rectangular corners than the rounded ones. So nowadays airplane windows have rounded corners.

A further improvement of the mechanical components in airplanes and other machines was obtained by deliberate generation of compressive residual stress in the surface of the metallic components, causing micro-cracks to stay closed and therefore reducing the chance of metal fatigue. Nowadays metal parts undergo treatment by shot peening, which adds this compressive stress to the top surface, and metal fatigue problems are largely overcome. Understanding crystallographic deformation, and the measurement by X-ray diffraction, are essential for making the safe and long-lasting machines that we use in our daily lives.

Electronics

Again, another area: microelectronic devices such as computers and cell phones have also become an essential part in our daily lives especially for the youngest generation. Cell phones have become so small and powerful because of our understanding of crystallography. With this understanding, we have created smaller and more powerful batteries, as well as energy-efficient components such as the backlight of the screens in our cell phones. Cell phone backlights are made from gallium nitride (GaN), a semiconducting material. These backlights consist of many thin layers which should have the right crystallographic properties for a good working device. Let’s have a look at controlled crystal growth.

GaN backlights, like other microelectronic components, consist of many layers of different materials which are grown on single-crystal substrates in chemical vapor deposition reactors. Depending on the growth conditions in the reactor, such layers can be relaxed: there’s no relation with the crystal structure of the substrate or strained: the layer is deformed and matches the crystallographic structure of the substrate. These strained layers are essential for the correct functioning of the device. X-ray diffraction is used to probe the crystallographic quality of these layers. Well-produced LEDs result in energy-efficient long-lasting cell phone screens. Again, understanding crystallography is essential for our daily lives.

 

 

 

Perfecting pharmaceuticals

The growth and aging of the world population ask for the availability of pharmaceutical materials for everyone. Understanding the crystallography of pharmaceuticals is essential for the development and production of safe medicines. The rotating molecule is Thalidomide, a drug developed in the 50s, which was found to have adverse effects on unborn children. A crystallographic property common in organic molecules is polymorphism: the ability of the molecule to crystallize in different forms.

 

 

 

Here, you see two forms of indomethacin, a strong painkiller. We need to understand these crystallographic forms in order to make safe pharmaceuticals. By measuring the crystallography, we can also check the authenticity of the drug. Counterfeiting of pharmaceuticals is a widespread problem and is a potential threat to the safety of our population. Counterfeiting is less risky than narcotics trafficking.

Here you see diffractograms of alpha and gamma indomethacin. Since the two polymorphs have different crystal structures, both diffractograms are different. X-ray powder diffraction is the only tool to readily distinguish between different polymorphs of a compound.

Crystals in your food

Crystallography is also important for feeding our growing population. Fertilizers are essential nowadays for improving the yield of agriculture. Understanding the crystallography of soils and fertilizers helps to optimize the fertilizer for the crops which are to be grown.

Coated chocolate
Coated chocolate in a diffractometer

Access to drinking water is a growing problem in many areas of the world. The water in our rivers is often too polluted, or used for irrigation, causing water shortages for the population downstream. Making drinking water from the sea so called desalination there’s a growing activity. Understanding the crystallography of the membranes and filters is important for building desalination plants with reduced power consumption. Finally, crystallographic substances are present in many food substances we take. Chocolate is a tasteful crystallographic substance. So, crystallography is not only essential for our daily lives, it also adds taste.

 

 

 

Written by: Martijn Fransen, Posted by: Malvern Panaltyical (www.materials-talks.com)