Author: edaxblog

Common Mistakes when Presenting EBSD Data

Shawn Wallace, Applications Engineer, EDAX

We all give presentations. We write and review papers. Either way, we have to be critical of our data and how it is presented to others, both numerically and graphically.

With that said, I thought it would be nice to start this year with a couple of quick tips or notes that can help with mistakes I see frequently.

The most common thing I see is poorly documented cleanup routines and partitioning. Between the initial collection and final presentation of the data, a lot of things are done to that data. It needs to be clear what was done so that one can interpret it correctly (or other people can reproduce it). Cleanup routines can change the data in ways that can either be subtle (or not so subtle), but more importantly they could wrongly change your conclusions. The easiest routine to see this on is the grain dilation routine. This routine can turn noisy data into a textured dataset pretty fast (fig. 1).

Figure 1. The initial data was just pure noise. By running it iteratively through the grain dilation routine, you can make both grains and textures.

Luckily for us, OIM Analysis™ keeps track of most of what is done via the cleanup routines and partitioning in the summary window on either the dataset level or the partition level (fig. 2).

Figure 2. A partial screenshot of the dataset level summary window shows cleanup routines completed on the dataset, as well as the parameters used. This makes your processing easily repeatable.

The other common issue is not including the full information needed to interpret a map. I really need to look at 3 things to get the full picture for an EBSD dataset: the IPF map (fig. 3), the Phase Map (fig. 4) and the IPF Legend (fig. 5) of those phases. This is very important because while the colors used are the same, the orientations differ between the different crystal symmetries.

Figure 3. General IPF Map of a geological sample. Many phases are present, but the dataset is not complete without a legend and phase map. The colors mean nothing without knowing both the phase and the IPF legend to use for that phase.

Below is a multiple phase sample with many crystal symmetries. All use Red-Green-Blue as the general color scheme. By just looking at the general IPF map (fig. 3), I can easily get the wrong impression. Without the phase map, I do not know which legend I should be using to understand the orientation of each phase. Without the crystal symmetry specific legend, I do not know how the colors change over the orientation space. I really need all these legends/maps to truly understand what I am looking at. One missing brick and the tower crumbles.

Figure 5. With all the information now presented, I can actually go back and interpret figure 3 using figures 4 and 5 to guide me.

Figure 4. In this multiphase sample, multiple symmetries are present. I need to know which phase a pixel is, to know which legend to use.

 

 

 

 

 

 

 

 

 

 

 

 

 

Being aware of these two simple ideas alone can help you to better present your data to any audience. The fewer the questions about how you got the data, the more time you will have to answer more meaningful questions about what the data actually means!

Happy Holidays from All of Us at EDAX!

Thank you to all the followers of our blog – we hope that you have been entertained, informed and amused by our posts this year. We will be taking a break until the second week of January 2019, but if you need any extra diversion over the holidays, don’t forget to take a look at the resources we have shared with you during the year and catch up on anything you may have missed.  We wish you a happy and healthy New Year and look forward to talking to you again in 2019.

All our on-demand webinars can be found here.  You can also find us on the following platforms:




Old Eyes?

Dr. Stuart Wright, Senior Scientist EBSD, EDAX

I was recently asked to write a “Tips & Tricks” article for the EDAX Insight Newsletter as I had recently done an EDAX Webinar (www.edax.com/news-events/webinars) on Texture Analysis. I decided to follow up on one item I had emphasized in the Webinar. Namely, the need for sampling enough orientations for statistical reliability in characterizing a texture. The important thing to remember is that it is the number of grain orientations as opposed to the number of orientations measured. But that lead to the introduction of the idea of sub-sampling a dataset to calculate textures when the datasets are very large. Unfortunately, there was not enough room to go into the kind of detail I would have liked to so I’ve decided to use our Blog forum to cover some details about sub-sampling that I found interesting

Consider the case where you not only want to characterize the texture of a material but also the grain size or some other microstructural characteristic requiring a relatively fine microstructure relative to the grain size. According to some previous work, to accurately capture the texture you will want to measure approximately 10,000 grains [1] and about 500 pixels per average grain in order to capture the grain size well [2]. This would result in a scan with approximately 5 million datapoints. Instead of calculating the texture using all 5 million data points, you can use a sub-set of the points to speed up the calculation. In our latest release of OIM Analysis, this is not as big of a concern as it once was as the texture calculations have been multithreaded so they are fast even for very large datasets. Nonetheless, since it is very likely that you will want to calculate the grain size, you can use the area weighted average grain orientation for each grain as opposed to using all 5 million individual orientation measurements for some quick texture calculation. Alternatively, a sub-set of the points through random or uniform sampling of the points in the scan area could be used.

Of course, you may wonder how well the sub-sampling works. I have done a little study on a threaded rod from a local hardware store to test these ideas. The material exhibits a (110) fiber texture as can be seen in the Normal Direction IPF map and accompanying (110) pole figure. For these measurements I have simply done a normalized squared difference point-by-point through the Orientation Distribution Function (ODF) which we call the Texture Difference Index (TDI) in the software.


This is a good method because it allows us to compare textures calculated using different methods (e.g. series expansion vs binning). In this study, I have used the general spherical harmonics series expansion with a rank of L = 22 and a Gaussian half-width of  = 0.1°. The dataset has 105,287 points with 92.5% of those having a CI > 0.2 after CI Standardization. I have elected only to use points with CI > 0.2. The results are shown in the following figure.

As the step size is relatively coarse with respect to the grain size, I have experimented with using grains requiring at least two pixels before considering a set of similarly oriented points a grain versus allowing a single pixel to be a grain. This resulted in 9981 grains and 25,437 grains respectively. In both cases, the differences in the textures between these two grain-based sub-sampling approaches with respect to using the full dataset are small with the 1 pixel grain based sub-sampling being slight closer as would be expected. However, the figure above raised two questions for me: (1) what do the TDI numbers mean and (2) why do the random and the uniform sampling grids differ so much, particularly as the number of points in the sub-sampling gets large (i.e. at 25% of the dataset).

TDI
The pole figure for the 1000 random points in the previous figure certainly captures some of the characteristics of the pole figure for the full dataset. Is this reflected in the TDI measurements? My guess is that if I were to calculate the textures at a lesser rank, something like L = 8 then the TDI’s would go down. This is already part of the TDI calculation and so it is an easy thing to examine. For comparison I have chosen to look at four different datasets: (a) all of the data in the dataset above (named “fine”), (b) a dataset from the same material with a coarser step size (“coarse”) containing approximately 150,000 data points, (c) sub-sampling of the original dataset using 1000 randomly sampled datapoints (“fine-1000”) and (d) the “coarse” dataset rotated 90 degrees about the vertical axis in the pole figures (“coarse-rotated”). It is interesting to note that the textures that are similar “by-eye” show a general increase in the TDI as the series expansion rate increases. However, for very dissimilar textures (i.e “coarse” vs “coarse-rotated”) the jump to a large TDI is immediate.

Random vs Uniform Sampling
The differences between the random and uniform sampling were a bit curious so I decided to check the random points to see how they were positioned in the x-y space of the scan. The figure below compares the uniform and random sampling for 4000 datapoints – any more than this is hard to show. Clearly the random sampling is reasonable but does show a bit of clustering and gaps within the scan area. Some of these small differences show up with higher differences in TDI values than I would expect. Clearly, at L = 22 we are picking up quite subtle differences – at least subtle with respect to my personal “by-eye” judgement. It seems to me, that my “by-eye” judgement is biased toward lower rank series expansions.


Of course, another conclusion would be that my eyesight is getting rank with age ☹ I guess that explains my increasingly frequent need to reach for my reading glasses.

References
[1] SI Wright, MM Nowell & JF Bingert (2007) “A comparison of textures measured using X-ray and electron backscatter diffraction”. Metallurgical and Materials Transactions A, 38, 1845-1855
[2] SI Wright (2010) “A Parametric Study of Electron Backscatter Diffraction based Grain Size Measurements”. Practical Metallography, 47, 16-33.

EM Microanalysis Business in China

Harris Jiang, Regional Sales Manager, EDAX China

The FY2018 is coming to the end within one month. The Chinese EM market has increased dramatically in the past 10 years. According to the data that Prof. Zhang Ze (the CAS academician, Chairman of Asian EM association) provided at the 2018 Chinese EM meeting in October in Chengdu, Tsinghua University purchased the first unit of Cs-TEM in 2008. However, the total volume of this product has grown enormously since that time. As to the EM microanalysis (EDS-EBSD-WDS) market, the whole market capacity has expanded dramatically. Figure 1 clearly shows the number of TEMs and SEMs in China. ¹

Figure 1. Number of electron microscopes in China. Data is up to 2016.

With the increase in China’s economy, the Chinese market is becoming a crucial one with the largest potential for EM companies. Each single segment market deserves full attention and investment. The development of advanced materials and advanced industrial manufacturing relies on smart design and precise engineering. Microstructural control is key, and comprehensive facilities and expertise in electron microscopy are needed for this. NSFC has provided financial support for hundreds of projects in universities and research institutes in recent years. ² It needs to be pointed out that the term “industry market” does not necessarily imply low-end market and “academic market” does not mean high-end market either. For example, the electronic/ semiconductor industry will be a good segment market which we should focus on in the future. The Chinese Government has invested a huge amount of resources in it [3] – and this is a high-end one. They are asking vendors to offer the best high-level EDS to detect nanostructure of less than 10 nm. For most customers, we need to develop a complete workflow and application solution in the niche market rather than just the most advanced products, and this helps us to grow together.

EBSD in China is currently becoming a hot topic and key segment product, especially since 2016. It is promising that EBSD applications in China have increased greatly and continue to grow. Most researchers are trying to add EBSD on their SEMs. As a sales manager, I have plenty of opportunity to visit customers who are from various different backgrounds. Although their application needs are customized, the demand for EBSD is still growing. High-end EBSD customers need an EBSD detector with high speed and high sensitivity. EDAX is able to offer different EBSD solutions tailored to a variety of applications and requirements. We are taking a long-term vision and expecting a tremendous change in the next ten years. We need to think bigger and more!

At EDAX we will be improving our product offerings in the coming years by developing specific application solutions and products for better cooperation with leading customers in each market segment. Secondly, we will also promote the capability of the service and application teams by developing a comprehensive training system and strengthening our human resources in China. Lastly, we are enhancing team collaboration and improving efficiency by clarifying the responsibilities of positions and optimizing internal communication.

For the Chinese market, EDAX provides specific EDS and EBSD products to both entry-level and high-end customers in each niche market. We believe that in the coming months and years we will be able to provide more solutions for customers’ fundamental research and technology development. We are hoping that we will have a bright future with the Chinese market.

References:
1. Ze Zhang, Xiaodong Han, Nature Materials volume 15, pages 695–697 (2016)
2. China Nature Science Foundation supports projects in 2017 [in Chinese] http://www.nsfc.gov.cn/publish/portal0/tab434/info70085.htm
3. China shatters annual fab construction investment record at US$7 Billion in 2018. http://www.semi.org/en/highlights-august-2018-edition-fab-databases

Visas, Border Crossings and Beers; Oh My!

Dr. Bruce Scruggs, Product Manager XRF, EDAX

It’s been a successful and busy year for EDAX’s XRF product lines and business. And with that, there’s a lot of traveling. I’m in the midst of filing a work visa application for a colleague and have determined that my absolute favorite work visa application as a US citizen is to Malaysia. It’s even more painful than having a snippy conversation with a Canadian border agent at the Montreal airport after flying back from Taiwan. (By the way, beer in Taiwan is light and forgettable.)

I’m going to go on about the Malaysian visa, but let’s just take a short diversion to this Canadian border agent. I was supposed to transit through Montreal airport but I missed my connecting flight. The airline was going to put me up for the night at a hotel near the airport. I had already filled out the purpose of my trip as “Business” on my Canadian landing card. I was returning from a business trip after all and there was no option for “Transit” as any sensible landing card would have. It wouldn’t have mattered a lick to the Canadian border agent monitoring the Transit Desk because I wasn’t going to Canada. I would have been transiting through Canada. But, instead, I was standing in front of the border agent controlling the mighty turnstile to Canada and my landing card said the purpose of my trip to Canada was “business”. I tried to explain that I wasn’t going to Canada. I was just transiting through Canada and had to stay at a local hotel overnight because of a missed flight, but the agent wasn’t having any of that. The landing card said that this was a “BUSINESS” trip and I was trying to enter “CANADA” and we needed to have a very grand discussion about the “BUSINESS” I was going to be doing in Canada. The agent was gesturing beyond the turnstile in the general direction of outside of the airport as he said “CANADA”. My voice began to rise as we went back and forth over the circumstances of our meeting at 10PM following my return flight from Taiwan. Finally, a voice in my head said “STOP! THIS IS NOT WORKING!”. Something my Mother said about kitchen condiments and flies crossed my mind. I lowered my voice. I took a deep breath. I told the agent that I had made a mistake on the card. I had missed my connecting flight home and I would have to stay at a local hotel overnight. I wouldn’t be doing any business in Canada and would be leaving in less than 14 hours. I was truly very sorry for the mistake on my landing card. “WELCOME TO CANADA!”, the agent said with another grand gesture in the direction of the airport exit. A quiet little voice in my head said “Whatever! You petty little dictator …” as I bit my lip. By the way, Canada has a lot of good beers. My favorite small breweries in Quebec include Brasserie Belgh Brasse, Microbrasserie Alchimiste, Microbrasserie Pit Caribou and Microbrasserie Charlevoix.

Anyway, back to the work visa for Malaysia. Malaysia is torture by a thousand paper cuts! All told, you need to submit a copy of your passport from front cover to back cover; a resume; a copy of your diploma; a job description; a work schedule; an employment verification letter confirming that no expenses for this person will be borne by the Malaysian Government; and an invitation letter. And don’t forget a recent passport photo. In JPG format. And make sure the diploma is provided in color. And the passport scan has to be in color, too! Oh, and the passport scan file is too large for our e-mail system. Can you upload that to Dropbox? Oh, you need to scan ALL the pages of the passport including the front and back covers. And which Malaysian consulate will you go to get the visa stamped in your passport? I hope you live around LA, DC or NYC. The staff at the DC consulate were very helpful. Otherwise you need to find a visa expeditor that will go to the Malaysian consulate for you.

Once this was all completed, I got the visa stamp – nothing says “Welcome to Malaysia” like:

But, once you get to Malaysia, one of my favorite Malaysian brewed beers is Anchor. Bon voyage!

Welcome to Weiterstadt!

Dr. Michaela Schleifer, European Regional Manager, EDAX

The European team had a very exhausting but successful week last week. Some months ago, we discussed the possibility of holding a user meeting at our headquarters in Weiterstadt, Germany. During our stay in Wiesbaden it became a tradition to do at least one user meeting or workshop a year. Because of our move to Weiterstadt and the development of some new structure in the European organization, it took quite some time to plan another user meeting. In spring time, we discussed how to satisfy the different areas in Europe regarding language and also how to transfer information about new technology to our distributors. We finally decided that we should organize 3 different meetings during the week of October 15th. The first two days were for our German speaking customers in Europe, mid-week we invited our distributors and on the last two days we offered a user meeting for our English-speaking customers. There was a lot of organization to be done, like making hotel reservations, preparing presentations, organizing hosting and also booking nice restaurants for the evening events. All of us were a bit nervous about whether everything would work, whether we had forgotten anything important and whether our SEM and system would work properly. The week before the meetings we installed the Velocity™ camera, our new high speed EBSD system in our demo lab and our application people were very happy with the performance and had fun playing around with it.

On Monday October 15th we started our first user meeting in the Weiterstadt office at around 1 pm with customers from the German speaking area. Around 45 participants joined the meeting. At the beginning we gave an overview of our current products and explained that our complete SDD series is using the Amptek modules with Si3N4 windows. Based on some spectra we showed the improved light element performance. After that Felix, one of our application specialists, showed our new user interface APEX™ live and the discussion which arose showed the interest from our users. Although only some users are doing EDS on a TEM we explained a little bit about the differences between EDS on a TEM and on a SEM. We finished the first day with a question and answer session and invited all the participants to a nice location in Darmstadt to have a typical German dinner together.

The next day was completely dominated by EBSD. Our EBSD product manager Matt Nowell, who came from Draper, USA to support us during our meetings, demonstrated the performance of our new Velocity™ EBSD camera. Matt also explained the differences in the camera technology using CCD or CMOS chips and described direct electron detection. It was easy to get more than 3000 indexed points per second while measuring a duplex steel with the Velocity™ camera. Our EBSD application specialist René de Kloe presented a lot of tips and tricks regarding EBSD measurements and analysis of measurement too and did not get tired of answering all the questions. At the end of our program all participants left with a good feeling having learnt a lot and got some good ideas about how to improve their measurements or what they might try to measure on their own samples.

The next day we shortened our program for our distributors and explained our product range and gave live demonstrations of APEX™ software platform and the Velocity™ CMOS EBSD camera. This day was dominated by a lot of discussions with the group and also by questions about our roadmap for 2019.

On Thursday and Friday of this week we did the same program for our English-speaking customers in Europe as we did for the German speaking customers. We had around 15 participants.

During this week we had around 75 customers in our office in Weiterstadt. Each customer was different in his applications and how he uses our systems but what we could observe during the evening was that most of them are very similar in what they like for dinner:

Late on Friday evening the whole European team was very happy that we managed the week with all the meetings and that based on the feedback we got it was a successful week. You may be sure that all of us went home and had a relaxing weekend!

I would like to thank Matt, Rene, Felix, Ana, Arie, Rudolf, Andreas and Paul and especially our customers who gave some interesting presentations about their institutes and the work they are doing there.

Old and New Faces

Dr. Jens Rafaelsen, Applications Engineer, EDAX

While I haven’t been around in the microscopy and microanalysis world in a professional sense for too long, it’s hard not to notice how often the faces stay the same but the title on the name tag or the company logo changes. Just to name a few from the EDAX side, Patrick Camus (Director of Engineering) used to work in applications for Noran, John Haritos (Southwest Region Sales Manager) came from Oxford, Sophie Yan (Applications) came from Zeiss, and Dave Durham (Western Region Sales Manager) came from Bruker.

Though microanalysis is a big field, it’s a small world once you get into the commercial side of it. I guess it shows that there are not too many of us that really have the deep level of interest and dedication to stay in field and the ones that do are often in short supply. While some of the changes could be a case of the grass being greener on the other side, it often seems to be driven by the desire for a career step or for personal reasons. The interesting part is that I have very rarely seen anyone hold a grudge or perceive a move to another company in the field as something negative.

Applications Engineer, Shangshang Mu

Applications Engineer, Shangshang Mu

Every year it seems like a couple of the old faces retire (though they often still show up at M&M, often wearing their last company shirt), but you start to recognize the rest of them despite any changes in affiliation. This makes it a little easier to identify the new faces and with that, I would like to introduce the newest one at EDAX: Shangshang Mu (pronounced Shong-shong) recently joined us as an applications engineer and will be based in our Draper, Utah office. He holds a PhD in Earth Sciences from Boston University and was most recently lab manager at Southeastern North Carolina Regional Microanalytical and Imaging Consortium. At EDAX, we are excited to have him on board and look forward to the rest of you getting to know him.