Evident InSight Blog

Tue, 24 Apr 2018 09:00:00 -0400

Thu, 19 Apr 2018 09:00:00 -0400

Tue, 17 Apr 2018 09:00:00 -0400

Vanta Handheld XRF Gets the Graphene Advantage

Tue, 03 Apr 2018 09:00:00 -0400

The X-ray detector in your analyzer has a small window that enables the X-rays to enter and reach the detector. Without this, the analyzer wouldn’t work. What this window is made of is important and impacts the effectiveness of your device. Light elements (like magnesium, aluminum, and silicon) have the weakest X-rays, so the thinner and lighter the window, the more of these X-rays can pass through. The more X-rays can pass through, the better the sensitivity of your XRF analyzer.

For a long time, the window was made of a beryllium foil. Beryllium is very light, but it’s hard to manufacture, fragile, brittle, and toxic. Even relatively slight impacts can damage the window, and, if it breaks, it’ll need to be replaced. Most beryllium windows are 8 microns or more thick.

Vanta^™ VMR models are now equipped with graphene detector windows that are only 0.9 microns thick, enabling better light element detection than conventional beryllium windows.

Advantages of graphene

Graphene is made of carbon; even though the window is very thin, it’s incredibly strong. Graphene windows allow more X-rays to pass through, increasing the analyzer’s sensitivity to key light alloy elements such as magnesium (Mg), aluminum (Al), silicon (Si), and even phosphorus (P) and sulfur (S). In addition, graphene is not toxic, unlike beryllium.

The unique benefits of graphene enable the Vanta model VMR handheld XRF analyzer to:

Detect magnesium (Mg) faster in aluminum alloys (0.53% Mg in 3 seconds of beam 2)
Achieve lower limits of detection for aluminum (Al) in nickel alloys
Measure silicon (Si) under 1000 ppm in low-alloy steels faster and with better precision
Measure phosphorus (P) and sulfur (S) in low-alloy steels below 0.035%

Accurate Alloy Analysis

Wed, 28 Mar 2018 09:00:00 -0400

This post was originally published on AZO Materials on September 27, 2016.

Alex Thurston, alloy applications specialist for portable XRF at Evident, talks to Stuart Milne at AZoM about the Vanta^™ handheld XRF analyzer and its powerful capabilities in industrial environments.

SM: Alloy analysis is important in many industries ranging from aerospace testing and pipeline analysis to scrap sorting and welding. What sets the Vanta analyzer apart from other handheld XRF devices currently on the market?

AT: Evident’ Vanta analyzer has numerous improvements that positively affect alloy testing and sorting.

First, it has been designed from the ground up to withstand the rigors of industrial environments for maximum uptime, faster ROI, and a lower cost of ownership. This includes drop testing to U.S. Military Standards (MIL-STD-810G) and a rating of IP65* for protection against dust and water ingress.

In addition to the rugged design, our new Axon Technology™ is a major leap forward in handheld XRF analytical performance. Axon Technology utilizes ultra-low-noise electronics to increase the resolution capability of the instrument, yielding accurate elemental detection in hard-to-determine energy regions. Software advancements have enabled a greater throughput of X-rays that can be counted, which improves the precision displayed to a user. And ultimately, increased precision means users can have greater confidence in their results.

SM: What features make Vanta analyzers better than other available devices for predicting possible in-service corrosion?

AT: In-service corrosion monitoring via handheld (HH) XRF is frequently concerned with two critical factors: computation of alloyed transition metals and silicon content. The Vanta analyzer excels at accurately quantifying these critical elements, especially in the spectrally-crowded transition metal region, such as chromium, nickel, and copper. Detecting light elements, like silicon, has benefitted greatly from a large increase in signal counts and increased resolution, providing better separation and more defined light element spectral peaks.

SM: How has the Vanta analyzer been developed to make the crowded iron-nickel-cobalt (Fe-Ni-Co) and magnesium-aluminum-silicon (Mg-Al-Si) regions easier to analyze?

AT: These are two unique aspects to spectral processing, especially for alloy identification. One is a very high signal and background region with several spectral overlaps (Fe-Ni-Co) and the other is a traditionally low count rate region that makes it difficult for analyzers to accurately quantify compositional levels less than 0.5%.

Vanta analyzers can easily quantify the Fe-Ni-Co region because of the extremely low noise and background associated with the spectral generation of the hardware and software. In addition, the increased resolution of the detector has enabled spectral processing to report much lower limits of cobalt (Co) than before due to reduced interference from the iron (Fe) peaks. The advancements of the Axon Technology have enabled us to define elemental peaks and valleys where we could not previously.

The Mg-Al-Si region has been improved with respect to the amount of representative X-rays that are generated from these elements and able to be counted as part of a useable spectra. In previous generations of handheld XRF, these elements barely generated enough signal, resulting in peaks that were not well defined. This made it difficult to accurately quantify these elements below 1000 ppm (0.1%). The Vanta analyzer, with its dramatically improved count rate, enables the instrument to precisely determine the amount of these elements present in far less time than has historically been needed.

SM: What developments have been made for increased lighter elemental analysis detection speed, and how has this resulted in greater throughput for sorting tasks?

AT: As mentioned, the count rate for these lighter element regions has been greatly increased. Due to the analyzer’s improved count rate, the display time for lighter elements is very fast. Previous HHXRF instruments displayed light element results that may not be entirely accurate on the screen to keep the user engaged — that tactic is no longer needed. Accurate results of low-Z number elements magnesium through sulfur can be quantified in just a few seconds. Reducing required testing times is the easiest way to increase throughput in sorting tasks. With the Vanta analyzer, being fast and accurate helps ensure the user’s success and confidence in sorting tasks with critical light element detection. All of these great light element analysis features are paired with robust analysis characteristics of elements with higher Z-numbers and melting points, which other handheld-based alloy identification systems may have difficulty in accurately analyzing.

SM: How is the Vanta analyzer able to offer highly precise results in QA/QC inspection activities?

AT: In addition to all of the hardware and software improvements that contribute to precise results, the Vanta analyzer has an expanded grade library to match more commonly used alloys across all bases of metals. In addition to more grades being included in the grade library, detailed grade match messages can be displayed, further informing users of overlapping grade considerations, casting-equivalency designations, and even similar chemistry characteristics of different alloys.

The combination of the grade and specification information that is available through the grade matching system coupled with the precise compositional results provide users with results they can trust when used as part of a QA/QC inspection system.

SM: How does the Vanta analyzer compare to lab-based systems?

AT: The incredible count rate that is possible the Vanta analyzer approaches many lab-based systems, all while using a lower power tube. The low-noise spectral generation possible with the Vanta analyzer affords users the flexibility of performing extremely precise testing, even when in the field.

SM: What impact does the analyzer’s improved physical envelope have on users in the field

AT: The Vanta analyzer is able to maintain all of the mentioned hardware and software improvements and still feature an IP65 rating*. Simply put, it was designed from the start for routine usage in tough environments. From drips and sprays to airborne dust, the Vanta analyzer can operate as expected with obstacles that were once considered a detriment to HHXRF operation. Other envelope design aspects were created for users wearing personal protective equipment (PPE), such as the touch-screen user interface, tactile joystick navigation capability, and a tool-less window change feature.

*M series analyzers are IP64 rated.

8 Tips to Improve Your High-Temperature Corrosion Thickness Measurements

Tue, 20 Mar 2018 09:00:00 -0400

Ultrasonic thickness gaging isn’t limited to testing materials at normal (ambient) temperatures. Measurements can be made on materials whose surface temperature approaches 900 °F (500 °C). When working with metals, there may be times when the thickness needs to be measured during an ongoing process where the test piece can’t be cooled down.

Heat can complicate the accuracy and efficiency of your measurements. If you use the wrong transducer, the heat can damage it and shorten its useful life. These 8 tips will help you overcome the challenges of testing hot materials.

Use a High-Temperature Dual Element Transducer
The thickness of hot corroded metal with rough surfaces should be measured using a high-temperature dual element transducer. It’s critical to choose a transducer that’s rated for use at the temperature of your inspection. Below are some of our most common high-temperature dual element thickness gage transducers:
- D790: for intermittent contact up to 932 °F (500 °C)
- D791: for intermittent contact up to 932 °F (500 °C)
- D797: for intermittent contact up to 752 °F (400 °C)
Use a High-Temperature Couplant
Special high-temperature couplants are required at temperatures greater than about 200 °F (100 °C). Standard B2 glycerin couplant is not rated for temperatures above 200 °F, so using it will result in a loss of signal and potential damage to the transducer. Instead, choose a high-temperature couplant that’s rated for the temperature of your inspection. A variety are readily available:
- H-2: medium-temperature couplant for use up to 750 °F (398 °C)
- I-2: high-temperature couplant for use up to 1250 °F (675 °C)
Use the 38DL PLUS^® Gage’s Temperature Compensation Feature
Sound velocity in all materials changes with temperature. Normally, the velocity increases as the material gets colder and decreases as it gets hotter, with abrupt changes near the freezing or melting points. Velocity changes are related to changes in elastic modulus and density, and, depending on the material and temperature range, the relationship can be significantly non-linear. Measuring hot materials with a thickness gage set to the sound velocity at room temperature can lead to incorrect readings.

For maximum accuracy, you need to account for the effect of the higher temperature on the velocity of sound. To do this, calibrate the gage’s sound velocity setting to the temperature where measurements will be made. This can be tedious and difficult to accomplish, but the 38DL PLUS gage includes a temperature compensation feature that, when active, automatically adjusts for the change in sound velocity based on temperature values that you enter before the inspection.
Increase the Thickness Gage’s Measurement Update Rate
Increasing your thickness gage’s measurement update rate helps to reduce the amount of time the transducer needs to be in contact with the hot surface.
Apply Couplant to the Tip of Your Transducer, Not the Surface of the Material
If you apply couplant to the surface of the hot material, it’ll most likely burn off before you can make a measurement. Instead, apply an appropriate couplant to the tip of the transducer, and couple it to the hot surface using firm pressure.
Limit the Transducer Contact Time to 5 Seconds
If you can’t obtain a valid thickness reading in 5 seconds, uncouple the transducer from the hot surface, apply more couplant to the tip of the transducer, and try again.

More advanced instruments, like the 38DL PLUS and 45MG gages, allow the user to freeze the measurement screen. This is a key feature that can be used for high-temperature measurements since it enables you to briefly couple onto the sample, press the FREEZE key, uncouple the transducer, and then make measurement adjustments to the frozen A-scan.
Regularly Perform a “Do ZERO”
We discussed that a material’s sound velocity changes with temperature, so as the delay lines within the dual element transducers heat up, they transmit sound at a different speed. To compensate for this, you should periodically perform a “Do ZERO.”

This can easily be done by first wiping the couplant off the face of the transducer and then pressing and releasing the 2nd F key followed by the CAL ZERO key. Pressing these keys causes the instrument to compensate for any thermal drift in the transducer.
Never Let the Transducer Get Too Hot to Hold
If the transducer starts to become too hot to hold with bare hands, let it cool in air or dip the face of the transducer in water. You should then re-zero by performing a “Do ZERO.”

Does this Glass Pass? Using XRF to Screen for Ceramic and Lead Contaminants

Wed, 14 Mar 2018 09:00:00 -0400

Dillon McDowell, one of our X-ray fluorescence (XRF) Applications Scientists, presented a paper at the 15th Asia Pacific Conference for Nondestructive Testing (APCNDT 2017) in Singapore.

Dillon’s paper, “Screening of Ceramic and Leaded Contaminants in Glass Recycling Streams via Handheld X-ray Fluorescence (HHXRF) Analyzers” was coauthored with Evident Applications Manager, Alex Thurston.

In the paper, Dillon discusses the techniques, drawbacks, and benefits of recycling glass and ceramic glass. One challenge that material recovery facilities (MRFs) face is that the magnetic and optical sorting systems they normally use to separate glass cullet from recycled glass are not effective at screening glass ceramic and leaded constituents from cullet streams. These contaminants lower the value of glass cullet to glass manufacturers. Handheld X-ray fluorescence analyzers are widely used since they can provide material chemistry results quickly. The results of this study demonstrate that HHXRF can detect even small quantities of ceramic elements in glass and glass cullet and that lead and color agents (iron (Fe) and copper (Cu)) can be reliably detected within seconds. Dillon also demonstrates that in-line XRF systems can be adapted to provide fast, reliable results that can keep up with the speed that cullet is typically measured.

Check out the presentation

Screening of Ceramic and Leaded Contaminants in Glass Recycling Streams using Handheld X-ray Fluorescence Analyzers from Evident IMS

Breaking Down the Technical Cleanliness Workflow Part 3: Particle Size Classification and Particle Count Extrapolation and Normalization

Thu, 01 Mar 2018 09:00:00 -0500

Particle size classes (differential and cumulative) and particle counts

In the third post of this six-part series, we look at particle size classification and particle count extrapolation and normalization. Here is where classification, extrapolation, and normalization fit into the overall technical cleanliness inspection process:

Preparation
- Extraction
- Filtration
- Drying and weighing
Inspection
- Image acquisition
- Particle detection
- Particle size measurement and classification
- Particle count extrapolation and normalization
- Contamination level calculation
- Cleanliness code definition
- Maximum approval check
- Separation of reflective and nonreflective particles
- Fiber identification
- Results review
- Reporting

Particle Size Classification

The outcome of the particle detection we covered in part 2 of this series is a sheet with the results of each detected particle. The size (typically the maximum Feret diameter) of each particle is listed. All particles are grouped into different size classes. This makes the subsequent report much shorter and enables a better comparison of measurements.

You can define the size classes. The classification parameters and how the classes should be divided are defined in various international standards. There are two major groups of size classes:

Differential classes: Size classes are defined by a minimum and a maximum particle size. Each particle is counted in only one class.

Cumulative classes: Size classes are defined by a minimum particle size. As a result, it’s possible that particles will be counted in more than one class.

Particle Size Classification

A defined area on the filter is scanned and checked for particles. Different filter areas (Fig. 1) are defined below.

Figure 1: Filter areas used in particle count extrapolation.

Filter size: A standard-size filter has a diameter of 47 mm, which results in a total filter area of 1735 mm².

Flow-through area: The filter is not completely covered with particles. Particles can only be in the area where the washing rinse went through the filter during the filtration process. This flow-through area can be set by the operator and must be a central circular area with a diameter less than 42 mm.

Maximum scan area: The maximum scan area has a diameter of 42 mm, which results in a total maximum scan area of 1385 mm².

Inspection area: The actual scan area can be defined by the user. Typically, the maximum possible scan area is used for the scan, but the inspection area can also be smaller. A smaller inspection area leads to fewer images and, thus, speeds up the time needed to inspect the filter.

All particles are detected when the flow-through area is completely inside the inspection area. If the inspection area is smaller than the flow-through area, the system needs to extrapolate the number of particles detected. The flow-through area must be set in your inspection software and will be used for particle count normalization.

Particle Count Normalization

The absolute or extrapolated count of particles must be normalized to a reference value.

Depending on the standard used and the filter tested, the measured number of particles is normalized to a comparison value. This enables you to compare multiple measurements, even if the examined samples are not the same size.

Depending on the method, a different value for normalization is used:

Washed area: Normalization on a washed surface area is used when the detected particles were washed from a sample surface. The resulting particle count is normalized to an area of 1000 cm².

Washed volume: Normalization on a washed sample volume is used when the detected particles were washed from a larger structured sample. The resulting particle count is normalized to an area of 100 cm³.

Washed parts: Normalization on washed sample parts is used when the detected particles were washed from a number of similar samples. The resulting particle count is normalized on a single sample part.

Filtered fluid: If the filtered fluid itself is analyzed and the detected particles are not washed from a sample, normalization has to be done on the amount of filtered fluid. The resulting particle count is normalized to a filtered fluid of 1 ml or 100 ml.

Note that the unit “cm³” is used for the washed volume and the unit “ml” is used for the filtered fluid. The different units are used to avoid mixing the values of washed sample volume and filtered fluid.

Following particle size classification and particle count extrapolation and normalization, contamination levels are checked for each particle size class. Check back for "Contamination Level Calculation," part four of six in our "Breaking Down the Technical Cleanliness Workflow" blog series.

Breaking Down the Technical Cleanliness Workflow Part 2: Image Acquisition and Measurement

The Value of a Turnkey Cleanliness Inspection System

Wed, 28 Feb 2018 15:46:00 -0500

How To: Add a Coating Model on Your Vanta Analyzer

Fri, 23 Feb 2018 09:00:00 -0500

Did you know that you can use a Vanta^™ XRF analyzer to accurately measure the thickness of a coating? If this is something you do regularly, setting up a coating model can help save you time. Creating the model is easy.

Select the right hand drop-down ‘gear’ symbol and select the ‘coating settings’ icon. When you do, you’ll see that silver (Ag) on copper (Cu) is the default. Select the ‘+’ icon to add a new model.

In the coating layer menu, write the name of the new model in the ‘name’ box. In this case, we’re calling it AgonCu5um. Below, there’s a drop-down menu that contains a list of elements from the alloy method beam 1 element suite. Select the appropriate element. In this case, we’re selecting silver on copper.

If your sample has multiple layers, select the ‘+’ icon to add another layer (you can create up to 3 layers). To remove a layer, simply double touch the trash icon.

It’s important note that when you’re using multiple layers, the analyzer counts the layer nearest the analyzer as the highest number layer.

Now we’re ready to conduct an optional one point calibration to help tune the analyzer to your sample. Press the ‘pencil’ icon. The default factor is set to 1, and the units are set to microns. Enter the target thickness for the standard of interest, and then select the ‘target’ icon to calibrate the instrument. The default time for the calibration is 10 seconds. Selecting a longer time will give you better precision. Select the ‘play’ icon to take the test.

Taking the test will recalculate the factor that has been set for the instrument and output the calculated thickness.

Without moving the sample, navigate to the live test screen and take a 10-second test. Notice that the coating name you selected appears at the top of the screen. The reported thickness will also show.

And that’s all there is to it!

Evident InSight Blog

Vanta Handheld XRF Gets the Graphene Advantage

Advantages of graphene

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Accurate Alloy Analysis

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Does this Glass Pass? Using XRF to Screen for Ceramic and Lead Contaminants

Check out the presentation

Breaking Down the Technical Cleanliness Workflow Part 3: Particle Size Classification and Particle Count Extrapolation and Normalization

Particle size classes (differential and cumulative) and particle counts

Particle Size Classification

Particle Size Classification

Particle Count Normalization

How To: Add a Coating Model on Your Vanta Analyzer

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