applications

Teaching is learning

Dr. René de Kloe, Applications Specialist, EDAX

Figure 1. Participants of my first EBSD training course in Grenoble in 2001.

Everybody is learning all the time. You start as a child at home and later in school and that never ends. In your professional career you will learn on the job and sometimes you will get the opportunity to get a dedicated training on some aspect of your work. I am fortunate that my job at EDAX involves a bit of this type of training for our customers interested in EBSD. Somehow, I have already found myself teaching for a long time without really aiming for it. Already as a teenager when I worked at a small local television station in The Netherlands I used to teach the technical things related to making television programs like handling cameras, lighting, editing – basically everything just as long as it was out of the spotlight. Then during my geology study, I assisted in teaching students a variety of subjects ranging from palaeontology to physics and geological fieldwork in the Spanish Pyrenees. So, unsurprisingly, shortly after joining EDAX in 2001 when I was supposed to simply participate in an introductory EBSD course (fig 1) taught by Dr. Stuart Wright in Grenoble, France, I quickly found myself explaining things to the other participants instead of just listening.

Teaching about EBSD often begins when I do a presentation or demonstration for someone new to the technique. And the capabilities of EBSD are such that just listing the technical specifications of an EBSD system to a new customer does not do it justice. Later when a system has been installed I meet the customers again for the dedicated training courses and workshops that we organise and participate in all over the world.

Figure 2. EBSD IPF map of Al kitchen foil collected without any additional specimen preparation. The colour-coding illustrates the extreme deformation by rolling.

In such presentations, of course we talk about the basics of the method and the characteristics of the EDAX systems, but then it always moves on to how it can help understand the materials and processes that the customer is working with. There, teaching starts working the other way as well. With every customer visit I learn something more about the physical world around us. Sometimes this is about a fundamental understanding of a physical process that I have never even heard of.

At other times it is about ordinary items that we see or use in our daily lives such as aluminium kitchen foil, glass panes with special coatings, or the structure of biological materials like eggs, bone, or shells. Aluminium foil is a beautiful material that is readily available in most labs and I use it occasionally to show EBSD grain and texture analysis when I do not have a suitable polished sample with me (fig 2) and at some point, a customer explained to me in detail how it was produced in a double layer back to back to get one shiny and one matte side. And that explained why it produces EBSD patterns without any additional preparation. Something new learned again.

Figure 3. IPF map of austenitic steel microstructure prepared by additive manufacturing.

A relatively new development is additive manufacturing or 3D printing where a precursor powdered material is melted into place by a laser to create complex components/shapes as a single piece. This method produces fantastically intricate structures (fig 3) that need to be studied to optimise the processing.

With every new application my mind starts turning to identify specific functions in the software that would be especially relevant to its understanding. In some cases, this then turns into a collaborative effort to produce scientific publications on a wide variety of subjects e.g. on zeolite pore structures (1, fig (4)), poly-GeSi films (2, fig (5)), or directional solidification by biomineralization of mollusc shells (3).

Figure 4. Figure taken from ref.1 showing EBSD analysis of zeolite crystals.

Figure 5. Figure taken from ref.2 showing laser crystallised GeSi layer on substrate.

Such collaborations continuously spark my curiosity and it is because of these kinds of discussions that after 17 years I am still fascinated with the EBSD technique and its applications.

This fascination also shows during the EBSD operator schools that I teach. The teaching materials that I use slowly evolve with time as the systems change, but still the courses are not simply repetitions. Each time customers bring their own materials and experiences that we use to show the applications and discuss best practices. I feel that it is true that you only really learn how to do something when you teach it.

This variation in applications often enables me to fully show the extent of the analytical capabilities in the OIM Analysis™ software and that is something that often gets lost in the years after a system has been installed. I have seen many times that when a new system is installed, the users invest a lot of time and effort in getting familiar with the system in order to get the most out of it. However, with time the staff that has been originally trained on the equipment moves on and new people are introduced to electron microscopy and all that comes with it. The original users then train their successor in the use of the system and inevitably something is lost at this point.

When you are highly familiar with performing your own analysis, you tend to focus on the bits of the software and settings that you need to perform your analysis. The bits that you do not use fade away and are not taught to the new user. This is something that I see regularly during the training course that I teach. Of course, there are the new functions that have been implemented in the software that users have not seen before, but people who have been using the system for years and are very familiar with the general operation always find new ways of doing things and discover new functions that could have helped them with past projects during the training courses. During the latest EBSD course in Germany in September a participant from a site where they have had EBSD for many years remarked that he was going to recommend coming to a course to his colleagues who have been using the system for a long time as he had found that the system could do much more than he had imagined.

You learn something new every day.

1) J Am Chem Soc. 2008 Oct 15;130(41):13516-7. doi: 10.1021/ja8048767. Epub 2008 Sep 19.
2) ECS Journal of Solid State Science and Technology, 1 (6) P263-P268 (2012)
3) Adv Mater. 2018 Sep 21:e1803855. doi: 10.1002/adma.201803855. [Epub ahead of print]

One, Two, Three Times an Intern

Kylie Simpson, Summer Intern at EDAX

Kylie ‘at home’ in the Applications Lab.

This summer was my third working for the EDAX Applications Team. It has been an amazing opportunity to be directly involved with research, customer support, and software testing here in Mahwah. I was able to continue with the APEX™ software testing that I worked on last summer which I found incredibly interesting because I’ve been able to observe the software evolve to best meet customer needs and improve in overall performance. I also had the chance to attend the Microscopy and Microanalysis (M&M) show in Baltimore, MD. This was an incredible experience for an undergraduate student, like me, interested in Materials Science and Microscopy. I was able to connect with people in the field, attend talks on topics at the forefront of Microscopy research, and present a poster that I have been helping out with this summer here at EDAX.

The majority of my time this year has been focused on helping Dr. Jens Rafaelsen, the head of the Mahwah Applications Team, with the data collection and analysis for a paper on the effects of Variable Pressure on EDS. Although Variable Pressure is an incredibly useful tool for studying SEM samples that are susceptible to charging, the introduction of gas to the specimen chamber has implications that must be considered when collecting EDS spectra. Additional gas particles in the SEM chamber lead to a scattering of the electron beam, known as beam spread or beam skirting.

In order to study and quantify this phenomenon, we used a double insulated Faraday cup with a 10 µm aperture, pictured below, to measure the unscattered beam at different pressures and working distances. We also modeled this beam scattering using Monte Carlo simulations that consider the SEM geometry as well as the type of gas in the chamber, which vary based on the type of SEM. Based on our experimental and theoretical results, we determined that as much as 85% of the electron beam is scattered outside of the 10 µm diameter high pressures of 130 Pa. This is much more scattering than we had anticipated, based on previous papers on this subject, making these results incredibly important for anyone using variable pressure in the SEM.

Double insulated Faraday cup with a 10 µm aperture.


Unscattered Beam Percentage vs. Pressure: Theoretical

Unscattered Beam Percentage vs. Pressure: Experimental

Overall, I am very thankful for the opportunities that EDAX has given me this summer and in the past. As a member of the Applications Team, I was able to work alongside the Engineering, Software Development, Customer Support, and Sales teams in order to help provide customers with the best analysis tools for their needs. I also gained a deeper understanding of the research, data collection, and analysis processes for writing a paper to be published: a truly incredible experience for an undergraduate student. Above all, the plethora of knowledge and experience of those here at EDAX and their willingness to share this information with me and others has been the most valuable aspect of my time here.

Down Memory Lane

Sia Afshari, Global Marketing Manager, EDAX

For years I have been attending the Denver X-ray conference (DXC) and it is hard when it coincides with the Microscopy and Microanalysis Conference (M&M) as it has a few times in the past several years. It is just difficult for me to accept that the overlap is not avoidable!

My interests are twofold, marketing activities where my main responsibility lie, and technical sessions which still pique my curiosity and which are beneficial for future product development. In the past couple of years at M&M, it has been great to attend sessions devoted to the 50 year anniversaries of electron microscopy, technical evolution, and algorithms, where my colleagues have either been the subject of presentations or have given papers. I have had the fortune to meet and, in some cases, to reacquaint with some of the main contributors to the scientific advancement of electron microscopy.

Being at M&M, I have missed the final years of attendance at DXC of the “old-timers” who have retired. These are gentlemen, in the true meaning of the word, whom I have had the honor of knowing for over 30 years and who have been more than generous with their time with me. I recognize most of all their devotion and contribution in advancing x-ray analysis to where it is today. Their absence will be felt especially in the development of methodology and algorithm. As a friend, who was frustrated with the lack of availability of scientists with a deep knowledge in the field, recently put it, “these guys don’t grow on trees.”

Back at M&M this year, I listened to Frank Eggert talking about the “The P/B Method. About 50 Years a Hidden Champion”, and he brought back many memories. I recognized most of his referenced names, and the fact that they are no longer active in the industry! Looked around the room, I saw more people of the same hair color as mine (what is left). I thought about the XRF/XRD guys I used to know and who are also no longer around the industry. The old Pete Seeger song popped up in my mind with a new verse as; “where have all the algorithmic guys gone?”

When the Dust of M&M Settles, It’s Time to Take Stock….

Shawn Wallace, Applications Engineer, EDAX 

Shawn presents our 2nd Lunch & Learn session at M&M 2018.

For an applications engineer, M&M is our biggest and most stressful event. Back to back demos while making sure everything is perfect to truly show off the best you can offer, with presentations and poster thrown in for good measure. There is no real time to reflect during the show, so as the dust settles, I always like to reflect on the year past and the one coming (in our world it seems as though the year really begins and ends in August).

Over the past year, the EDAX EBSD world has seen major changes with the release of the Velocity™ detector. It was well received by our customers, which puts a smile on my face. Over the next year, you guys will have the system to play with and will really learn the power of it, showing that our hard work and time spent has really paid off. There is so much more in the works on the EBSD side that I wish I could tell you about. Stay tuned for that ride. It should be fun and exciting.

Velocity™ EBSD Camera

As for the EDS world, the release of the Elite T was a great group effort with many small changes behind the scenes making big differences to the product, with more to come.
That said, APEX™ still seems to steal the spotlight (sorry Matt!). With features being added quickly to each internal build, we see our customers’ needs being fulfilled one line of code at a time and in time, you will see them too.

EDAX webinar series.

While hardware and software are key, I think that it is just as important to reflect on all the interactions we have at the show with all our customers, partners and friends. It helps me understand what we did right (and wrong) on our journey in the last year. Between workshops, onsite training sessions, and shows, I see customers both at their work sites, seeing what they are working with, and out at a neutral site learning from their colleagues about what’s new in tech or new ways to answer interesting questions. This helps us all to understand your needs and wants, and where we as a community are going and growing.

With that in mind, I am turning this blog back over to you. Where do you see microanalytical technology going in the next year? What application areas do you see expanding? What is the best way for us to disseminate information to you, our users? (webinars, videos, blogs, workshops?) We invite you to Leave a Reply via the link below.

Vacationing Between a Rock and a Hard Place?

Shawn Wallace, Applications Engineer, EDAX.

One of the perks of both my degree (Geology) and my current job is that I have travelled extensively. In all those travels, I had been to 47 of the 48 contiguous US States, with Maine being the missing one. This year, I decided to be selfish and dragged the family to Maine on vacation, so I that could tick off the final one.

Being a member of the Wallace family means vacation is a time for strenuous hikes and beating on rocks to unlock their inner goodies, to add to our ever growing rock and mineral collection. This vacation was no different. Maine is home to some of the best studied and known Pegmatites, and they quickly became our goal. Pegmatites are neat for a several reasons, the main two being that they tend to form giant crystals (a 19 foot long Beryl found in Maine) and weird minerals in general tend to form in them.

I was able to track down some publicly accessible sites, found a lovely home base to rent for the week, and we set off for a week long rockhounding adventure. Ok not all week. We took a couple days off to go swimming, as it got up over 90F (>32C).

Figure 1. Dendrites cover this massive feldspar sample on nearly all faces.

Our first stops yielded the usual kind of rocks I was expecting, but another site did not. There we found dendrites everywhere. The rock itself is a massive feldspar (Fig. 1). You can see that most of the dendrites nucleate at the edge of a fracture surface and then do their fractal thing on the surface itself. Wanting to better understand the sample, I started searching for previous EBSD work on geological dendrites. While a lot exists in the metals world, very little exists in the geological world. To me, this means I have work to do. Let’s see what I can do to get some useful data on this sample!

P.S. I have Alaska and Hawaii to go. Who needs an onsite training in those states? 😉

Crown Caps = Fresh Beer?

Dr. Felix Reinauer, Applications Specialist Europe, EDAX

A few days ago, I visited the Schlossgrabenfest in Darmstadt, the biggest downtown music festival in Hessen and even one of the biggest in Germany. Over one hundred bands and 12 DJs played all kinds of different music like Pop, Rock, Independent or House on six stages. This year the weather was perfect on all four days and a lot of people, celebrated a party together with well known, famous and unknown artists. A really remarkable fact is the free entrance. The only official fee is the annual plastic cup, which must be purchased once and is then used for any beverage you can buy in the festival area.

During the festival my friend and I listened to the music and enjoyed the good food and drinks sold at different booths in the festival grounds. In this laid-back atmosphere we started discussing the taste of the different kinds of beer available at the festival and throughout Germany. Beer from one brewery always tastes the same but you can really tell the difference if you try beer from different breweries. In Germany, there are about 1500 breweries offering more than 5000 different types of beer. This means it would take 13.5 years if you intended to taste a different beer every single day. Generally, breweries and markets must guarantee that the taste of a beer is consistent and that it stays fresh for a certain time.

In the Middle Ages a lot of people brewed their own beer and got sick due to bad ingredients. In 1516 the history of German beer started with the “Reinheitsgebot”, a regulation about the purity of beer. It says that only three ingredients, malt, water, and hops, may be used to make beer. This regulation must still be applied in German breweries. At first this sounds very unspectacular and boring, but over the years the process was refined to a great extent. Depending on the grade of barley roasting, the quantity of hops and the brewing temperature, a great variety of tastes can be achieved. In the early times the beer had to be drunk immediately or cooled in cold cellars with ice. To take beer with you some special container was invented to keep it drinkable for a few hours. Today beer is usually sold in recyclable glass bottles with a very tight cap keeping it fresh for months without cooling. This cap protects the beer from oxidation or getting sour.

Coming back to our visit to the Schlossgrabenfest; in the course of our discussions about the taste of different kind of beer we wondered how the breweries guarantee that the taste of the beer will not be influenced by storage and transport. The main problem is to seal the bottles gas-tight. We were wondered about the material the caps on the bottles are made of and whether they are as different as the breweries and maybe even special to a certain brewery.

I bought five bottles of beers from breweries located in the north, south, west, and east of Germany and one close to the EDAX office in Darmstadt. After opening the bottles, a cross section of the caps was investigated by EDS and EBSD. To do so, the caps were cut in the middle, embedded in a conductive resin and polished (thanks to René). The area of interest was the round area coming from the flat surface. The EDS maps were collected so that the outer side of the cap was always on the left side and the inner one on the right side of the image. The EBSD scans were made from the inner Fe metal sheet.

Let´s get back to our discussion about the differences between the caps from different breweries. The EDS spectra show that all of them are made from Fe with traces of Mn < 0.5 wt% and Cr, Ni at the detection limit. The first obvious difference is the number of pores. The cap from the east only contains a few, the cap from north the most and the cap from the middle big ones, which are also located on the surface of the metal sheet. The EBSD maps were collected from the centers of the caps and were indexed as ferrite. The grains of the cap from the middle are a little bit smaller and with a larger size distribution (10 to 100 microns) than the others, which are all about 100 microns. A remarkable misorientation is visible in some of the grains in the cap from the north.

Now let´s have a look at the differences on the inside and outside of the caps. EDS element maps show carbon and oxygen containing layers on both sides of all the caps, probably for polymer coatings. Underneath, the cap from the east is coated with thin layers of Cr with different thicknesses on each side. On the inside a silicone-based sealing compound and on the outside a varnish containing Ti can also be detected. The cap from the south has protective coatings of Sn on both sides and a silicon sealing layer can also be found on the inside. The composition of the cap from the west is similar to the cap from the east but with the Cr layer only on the outside. The large pores in the cap from the middle are an interesting difference. Within the Fe metal sheet, these pores are empty, but on both sides, they are filled with silicon-oxide. It seems that this silicon oxide filling is related to the production process, because the pores are covered with the Sn containing protective layers. The cap from the north only contains a Cr layer on the inside. The varnish contains Ti and S.

In summary, we didn’t expect the caps would have these significant differences. Obviously, the differences on the outside are probably due to the different varnishes used for the individual labels from each of the breweries. However, we didn’t think that the composition and microstructure of the caps themselves would differ significantly from each other. This study is far from being complete and cannot be used as a basis for reliable conclusions. However, we had a lot of fun before and during this investigation and are now sure that the glass bottles can be sealed to keep beer fresh and guarantee a great variety of tastes.

Building an EBSD Sample

Matt Nowell, EBSD Product Manager, EDAX

Father’s Day is this weekend, and I like to think my kids enjoy having a material scientist for a father. They have a go-to resource for math questions, science projects are full of fun and significant digits, and when they visit the office they get to look at bugs and Velcro with the SEM. I’m always up to take them to museums to see crystals and airplanes and other interesting things as we travel around. That’s one way we have tried to make learning interactive and engaging. Another activity we have recently tried is 3D printing. This has allowed us to find or create 3D digital models of things and then print them out at home. Here are some fun examples of our creations.
At home we are printing with plastics, but in the Material Science world there is a lot of interest and development in printing with metals as well. This 3D printing, or additive manufacturing, is rapidly developing as a new manufacturing approach for both prototyping and production in a range of industries including aerospace and medical implants. Instead of melting plastics with a heated nozzle, metal powders are melted together with lasers or electron beams to create these 3D shapes that cannot be easily fabricated by traditional approaches.

In these applications, it is important to have reliable and consistent properties and performance. To achieve this, the microstructure of the metals must be both characterized and understood. EBSD is an excellent tool for this requirement.

The microstructures that develop during 3D printing are very interesting. Here is an example from a Ni-based superalloy created using Selective Laser Melting (SLM). This image shows a combined Image Quality and Orientation (IQ + IPF) Map, with the orientations displayed relative to the sample normal direction. Rather than equiaxed grains with easily identifiable twin boundaries, as are common with many nickel superalloys, this image shows grains that are growing vertically in the structure. This helps indicate the direction of heat flow during the manufacturing process. Understanding the local conditions during melting and solidification helps determine the final grain structure.
In some materials, this heating and cooling will cause not only melting, but also phase transformations that also affect the microstructure. Ti-6Al-4V (or Ti64) is one of the most common Titanium alloys used in both aerospace and biomedical applications, and there has been a lot of work done developing additive manufacturing methods for this alloy. Here is an IQ + IPF map from a Ti64 alloy built for a medical implant device.
At high temperatures, this alloy transforms into a Body-Centered Cubic (or BCC) structure called the Beta phase. As the metal cools, it transforms into a Hexagonal Closed Pack (HCP) structure, called the Alpha phase. This HCP microstructure develops as packets of similarly oriented laths as seen above. However, not all the Beta phase transforms. Here is an IQ + Phase EBSD map, where the Alpha phase is red and the Beta phase is blue. Small grains of the Beta phase are retained from the higher temperature structure.
If we show the orientations of the Beta grains only, we see how the packets relate to the original Beta grains that were present at high temperatures.
The rate of cooling will also influence the final microstructure. In this example, pieces of Ti64 were heated and held above the Beta transition temperature. One sample was then cooled in air, and another was quenched in water. The resulting microstructures are shown below. The first is the air-cooled sample.
The second is the water-cooled sample.

Clearly there is a significant difference in the resulting structure based on the cooling rate alone. As I imagine the complex shapes built with additive manufacturing, understanding both the local heating and cooling conditions will be important for optimization of both the structure and the properties.