We have started making a new science video about X-Ray fluorescence spectroscopy (XRF). In this 6 minute video we will explain with 3D animations the basics of this materials characterization technique and do a demonstrations where we use XRF to measure the elemental composition of an ancient coin.
This video will be published in October 2016.
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Contact us and ask for further details if you are interested in collaboration.
The lifespan of a device is often limited by a specific component that fails first due to corrosion. Finding a suitable corrosion prevention method however can be difficult at best but sometimes it is even nearly impossible. We have plenty of experience with various corrosion prevention techniques and our partners at the University of Tartu use nanotechnology to develop novel methods for the protecting materials against corrosion on daily basis. If you have unique problem with corrosion, then contact us and we can discuss if and how it is possible to solve it.
If your company offers products or services that are related to corrosion or materials characterization, then we can promote it on our website.
Individuals and companies can become our partners and earn a share from the profit from each client brought to us.
We create free high quality educational video materials that are often ranked first or among the first ones in YouTube on the relevant topic search.
Under the Scanning Electron Microscope Series
In this series we will use a powerful scanning electron microscope to reveal the invisible nano-scaled world and study common and uncommon stuff in unprecedented detail. Take a look at our current videos in this series to get an idea. We accept sponsors to these videos who are interested in popularizing science and want to show their contribution to a large audience.
Materials Characterization Techniques
We regularly make mini video lectures, where we explain the basics of materials characterization techniques with the help of 3D animations and practical examples. Check out our videos about low-energy ion scattering spectroscopy, infrared spectroscopy and x-ray fluorescence spectroscopy to get an idea. To future similar videos, we accept companies as sponsors who produce scientific equipment that is covered in the video. Our next video topics are X-ray diffraction analysis, ellipsometry, scanning tunneling microscopy, Raman spectroscopy, dynamic light scattering and optical microscopy. All these videos are based on the Captain Corrosion Handbook of Materials Characterization.
Forms of Corrosion & Corrosion Prevention Techniques
There are many different forms of corrosion and since we have many years of experience with this field, we will share our experience in public videos. See our video about galvanic corrosion to get an idea. These videos are based on the Captain Corrosion Handbook of Corrosion. For sponsoring, we accept companies who make or sell anti-corrosion products, corrosion testing equipment or who want to demonstrate how their products are made resistant to corrosion and last longer than their competition.
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Need a product or its working principle animated in 3D?
We got years of experience with 3D modelling as we make free study materials. For a fair price we can also create an animation for you! Just contact us and let us know what you need.
Need to test the corrosion resistance of your material or a protective coating?
In collaboration with the University of Tartu we can do both chemical and electrochemical tests to simulate real or even extreme conditions in order to evaluate the performance of your sample.
Contact us if you are interested in corrosion testing!
Chemical tests – Studied substrates are exposed to a corrosive environment similar to the real conditions where it will be used later on. We can also alter the conditions of the environment to make it more corrosive by adjusting the pH and temperature or include UV light. A common example would be a test of series to compare the quality of stainless steel samples obtained from different suppliers. Another example would be the evaluation of different protective coatings on metal substrates.
Electrochemical tests – Corrosion can electrochemically be accelerated and this allows to quickly obtain reliable information about a materials or protective coatings corrosion resistance. For instance, certain metal alloys can be immersed in a salty water for years before it corrodes while electrochemically we can evaluate its long-term performance within a hour.
Microscopy – In addition to corrosion tests we also do microscopy studies of the tested substrates in order to get additional information about the type of corrosion. For example, Pitting corrosion often occurs undetected as it stats as a tiny hole on the surface and forms a network of tunnels inside the substrate, thus greatly degrading its mechanical properties. In contrast, uniform corrosion initially affects the aesthetic appearance of a material and mechanical properties are not much affected if the problem is dealt with.
Do you require more information about a certain material used in your products but don`t have the necessary equipment or knowledge?
In collaboration with the University of Tartu we can study your material with state of the art techniques in unprecedented detail and provide you with the needed information.
Contact us if you are interested in materials characterization services!
Here is a list of some common techniques used in our daily research and their possible applications:
Scanning electron microscopy (SEM) – Used to obtain high resolution images of a materials surface with a magnification far greater than in the case of optical microscopes. SEM can also be used to study the distribution of different elements in a microscopic scale or even locally (few microns area) measure the elemental composition of a material. SEM is also a valuable tool to visualize microscopic cracks and defects in a material that affect its mechanical properties. Another useful application of SEM is to study the individual grain size of powders and also evaluate the size distribution. Learn more by watching our educational video and visiting our gallery.
X-ray fluorescence spectroscopy (XRF) – Quick and easy way to precisely study the average elemental composition of various materials such as a metal alloys, ceramics and polymers. For instance, we can use XRF to verify if your supplier provides you with the metal alloy that you requested and also see if it contains any unwanted impurities. Learn more by watching our educational video.
Atomic force microscopy (AFM) – Allows to measure the roughness and surface details of extremely smooth surfaces such as glass or various fine polished materials. For example, the nano scaled roughness plays a significant role in the performance of self-cleaning windows. Learn more by watching our educational video.
X-ray diffraction (XRD) – Gives information about the crystal structure of bulk materials, powders and thin films. For instance, XRD allows to verify if a titanium dioxide powder is amorphous, anatase, rutile or a mixture. It can also give information about the effect of different thermal treatments on a metal.
Contact us and briefly describe your technological problem which related to corrosion or materials science. We will do our best to solve the problem or at least point you in the right direction.
Corrosion consultation by Captain Corrosion is for free!
However, if you are satisfied with the consultation, you can tip us via PayPal. All the money is used for making educational science videos.
Low-energy ion scattering spectroscopy (LEIS) is an exciting technique that allows to study the structure and chemical composition of a materials surface.
In this materials characterization method the sample is bombarded with a stream of ions and the positions, velocities and energies of the scattered ions are observed. The energy of scattered ions depends on the mass of the target, so there are distinct peaks in the energy spectrum of the scattered ions. These peaks give information about the samples elemental composition. The uniqueness of this technique lies in its sensitivity to the very first atomic layer on a sample and with forward scattering setup it is even capable of directly observing hydrogen atoms.
One of the main components of the system is the ion gun, that shoots ions at the studied substrate. The most widely used ions for that purpose are ionized noble gas or alkali atoms. Noble gas such as helium, neon or argon is ionized with electrons, giving them a positive charge. Alkali ion beams can be created by heating alkali wafers. In low-energy ion scattering spectroscopy the ions usually have an energy from 500 eV to 10 000 eV. The precise desired energy of the ions is obtained by applying a suitable accelerating voltage.
Before interacting with the substrate, the ions first need to pass through the ion beam manipulator, that narrows the beam and also filters the ions based on mass and velocity. For some experiments the ion beam is also chopped with an unipolar electrical chopper – a pulsed-wave generator, that lets through ions only when no voltage is applied. As a result the ion beam leaves the ion beam manipulator in pulses. By using short ion pulses, one can separate backscattered primary ions, for example He, from sputtered ions of different masses by time gating. This makes it possible to detect signals that would otherwise be buried in the background that is caused by ions sputtered from the sample surface.
The sample itself is attached to a special holder that allows the operator to adjust the position and angle of the sample for different experiments. When the ions hit the substrate, different interactions take place. Some ions are scattered at a certain angle and also their energy will be different after the impact. Some ions however become neutral as they pick up electrons from the substrate. The ions may also be implanted into the material or deposited on the substrate surface. The primary beam ions may also kick out electrons or atoms from the substrate and the atoms may even be ionized in the process. Radiation may also be emitted from the substrate as the excited atoms undergo a relaxation process.
The electrostatic analyzer is commonly used to detect the velocities and energies of the scattered ions. In this hemispheric device an electrical potential is applied between the inner and outer wall. The outer wall with positive potential repels the positive ions and the inner wall with negative potential attracts the positive ions. Neutral particles are unaffected by the field and hit the wall and thus never reach the detector. Positive ions with too low energy are pulled to the inner wall and also don’t reach the detector. If the cations energy is too high however then it simply hits the outer wall. Only if the ions energy is just right, it can pass through the analyzer and create a signal by interacting with the detector. By changing the potential between the walls, the operator can scan through a wide energy range in order to find out the energy of the emitted particles. In newer systems however a double toroidal analyzer is preferred as it integrates the signal over the scattering azimuth, so the intensity is some orders of magnitude higher compared to a hemispherical analyzer. The drift tube is used in TOF experiments in order to detect the energies and velocities of the scattered ionic and also neutral particles. Neutrals can easily be seperated from ions with the accelerator. There are two types of detectors that are commonly used – channel electron multipliers and microchannel plates. If the ion or a neutral particle with sufficient energy hits the detector then a cascade of secondary electrons is created and the signal significantly amplified. Microchannel plates also give information about the particles position but that comes at the cost of sensitivity.
Measurements with low-energy ion scattering spectroscopy are performed in ultra-high vacuum in order to avoid interactions with the surrounding gas. Having a good vacuum also ensures that the studied substrate and system parts are clean. Ultra-high vacuum is achieved with turbomolecular and ion pumps with the help of rough vacuum pumps.
Samples that have been exposed to open air are always contaminated for this type of surface sensitive characterization method and therefore they need to be cleaned inside the system in vacuum with appropriate equipment. Common ways to remove the contaminated top layer are sputtering, annealing or exposing to atomic oxygen.
There are of course few other surface sensitive materials characterization techniques such as XPS, AFM and SEM but each of them has distinct advantages and disadvantages. Therefore they are often used together when studying novel nanomaterials as they compensate each others weaknesses and allow to get a better overview.
Leak finder for vacuum systems is explained and demonstrated in this short video. All you need is a spectrometer tuned for helium and a tank of helium. In order to find the leak, you need to expose the vacuum system locally to helium. If a leak is present then the gas is sucked inside and pumped out into the mass spectrometer. The beeping noise immediately alerts the user if helium has reached the spectrometer and the leak is found. The most common places for leaks are usually at the connections of the vacuum systems parts.
The quadrupole mass spectrometer (QMS) is used to detect and measure the abundance of gas phase ions. These ions have to pass between electrically connected rods in order to reach the detector. By combining alternating and direct voltage on these rods, it is possible to ensure that only ions with specific mass-to-charge ratio are capable of reaching the detector.