We offer hands-on equipment training with our team members on all of our equipment. Training for the equipment can range from one to three sessions depending on the user's familiarity with the techniques. Usually, an MCL team member will conduct the first training session in which the trainer is operating the equipment and teaching. Subsequent training sessions will take place with the user operating the equipment and a member of the MCL team would be supervising. If necessary, we can do a third training session on equipment or training sessions on the analysis tool.
For any X-ray use on campus, users need to go through "X-ray radiation safety training" through the Radiation Safety Office(RSO). There are two parts to this training, 1) an online portion and 2) an in-class seminar. You must sign up and attend the "Analytical X-ray In-Person Class" before a certificate will be sent to us. You can find information on how to do the online training and schedule for the in-person training at the Radiation Safety Office's website. After we've received your "Radiation Safety Training for Analytical X-Ray" Certificate, we can then train you on the X-ray diffraction (XRD) systems. Note that the in-class seminar is taught once a month.
For those users who would prefer the lab to provide their sample's data from our equipment, our team members can run the instruments for you, collect the data, and send that information to you for analysis.
In addition to providing training for new users, the MCL team is available to help users in the design of experiments, analyze the data, and interpret the results.
In general, macroscopic refers to objects or phenomena that are visible to the naked eye. This is in contrast to microscopic, which refers to magnifying instruments necessary to observe very small objects or phenomena. When observing something on the macroscopic scale, you're measuring some type of bulk property, which is based on a collective system as a whole, rather than on a molecular or unit cell basis.
The types of instruments in the MCL that can measure these types of properties include the following:
Differential scanning calorimetry
We have a differential scanning calorimeter (DSC) that measures the thermal properties of a material, such as melting point (Tm), glass transition temperature (Tg), crystallization point (Tc), heat capacity (Cp), study liquid crystal (LC) phases and transitions, exothermal energy from a polymer cure that can determine degree and rate of cure, and much more.
We have a dilatometer that measures the amount of expansion of a material as the temperature increases. Dilatometry is very useful in determining a material's coefficient of thermal expansion (CTE).
We have an Instron mechanical test frame (MTF) or universal testing machine (UTM) measures compression, flexure, and tensile properties of a material.
- Compressive strength refers to the ability of a material or structure to withstand loads tending to compress or reduce the size of that material or structure.
- Flexural strength or bend strength refers to the ability of a material or structure to withstand loads using a three point flexural test as the material or structure is bent until fracturing or yielding while extending across a distance.
- Tensile strength or ultimate tensile strength refers to the ability of a material or structure to withstand loads tending to elongate or increase the size of that material or structure.
Surface Area & Pore Size Analysis
We have a BET surface area and pore size analyzer that measures surface area and pore size of powder, small rocks, and similar materials.
- The Brunauer–Emmett–Teller (BET) method uses the physical adsorption of gas molecules on a solid surface to measure the specific surface area of materials.
We have a digital scale that measures the mass of a sample from 0 to 109 g to the 0.1 mg.
Optical microscopy is an imaging technique with visible light and a system of lenses to observe samples at several hundred times magnifications. Images are captured with a digital camera connected to a computer.
Metallography is the study of the physical structure and components of metals with microscopy. A metallographic microscope is an inverted stage optical microscope where your sample is facing down towards a lens. Samples have to be prepared by mounting in a resin, then grinding, polishing, and sometimes etching. Depending on the type of samples, certain microstructural features can be observed with a few being crystal grain boundaries, intermetallic layers, and crack formations that can help determine the types of physical stresses placed on the sample beforehand. Knowing the types of physical stresses is very useful in some types of root cause failure analysis.
For certain types of analysis, samples have to be prepared as a cross-section or microsection to view features that are inside the sample. Metals, mostly homogeneous samples, are cross-sectioned to view grain size, structure, and quality.
Electronics assemblies and other items that are combinations of different types of materials are cross-sectioned to verify structure and quality, as well as to help determine failure modes. Electronics can contain glass fibers, Kapton®, copper, acrylic adhesive, epoxy, Teflon®, solder, etc. Circuit boards are typically composites of glass fibers and epoxy laminates. These materials can each have different relative hardness, as well as the mounting media, which makes a successful microsection of an electronics assembly difficult.
The cross-section begins with selection and removal of an area to analyze from a sample. You can remove the section from a sample with routing, sawing, or punching, but each method adds mechanical stress which can damage the area in question. Punching or shearing is an easy method for removing a section, but it adds the most mechanical stress, due to embedded fibers transferring mechanical force to the rest of the composite. Routing and sawing remove both all of the materials in the composite to remove a section from a larger sample.
Multiple materials, mostly acrylic or epoxy resins, are available for mounting samples. They have differences in cure time, resin retraction, adhesion to the sample, matching sample hardness, conductivity, and so on. You place the section in a sample cup and make sure its a vertical as possible, usually with the aid of small plastic or metal spring clips. The resin is poured on one side of the sample and a small vacuum is pulled to ensure that all the air is driven out and the resin fills in all of the spaces, completely embedding the sample.
Cross-Sectioning or Microsectioning
The sample was ground successively with finer and finer grits of grinding paper in a stepwise manner and then polished with a fine alumina slurry until the desired location is visible. After a final polish, the sample can be examined with a metallographic microscope and/or scanning electron microscope (SEM).
One of the main issues with resin-embedded samples is that there is an electric charge build up, especially at the higher accelerating voltages when viewing a sample with a SEM, as well as performing elemental analysis with energy dispersive X-ray spectroscopy (EDS). At the very least, this charging interferes with imaging of the sample in a typical SEM. To achieve the best results, you should coat the sample with a thin conductive layer to dissipate any charge that is introduced by the SEM-EDS. We have the ability to coat samples with conductive carbon or gold layer.
Scanning electron microscopy (SEM) is an imaging technique where you can observe samples from 15 to 60,000x magnifications. If the sample conditions are optimized, then even higher magnification images can be captured. Accelerated electrons are used as the illumination source since the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, which are used in optical microscopy.
One of our SEMs can perform energy dispersive X-ray spectroscopy (EDS) with which you can capture the elemental composition of samples. EDS is a very useful technique to identify metals, metal alloys, metal oxides, metal nitrides, metal sulfides, and so on.
Spectroscopy is the study and measurement of spectra produced when matter interacts with or emits electromagnetic radiation.
Fourier Transform Infrared Spectroscopy
Fourier transform infrared spectroscopy (FTIR) involves the absorption or transmission of infrared light. FTIR spectra show peaks that correspond to vibrational modes of carbon-containing molecules, which can be used to identify an organic compound.
Ultraviolet-visible-near-infrared spectrophotometry (UV-Vis-NIR) involves the absorption or transmission of light. UV-Vis-NIR spectra show peaks that correspond to quantum energy levels, such as absorbing light at a certain wavelength excites a material's electrons from its ground state to higher energy levels. After calibrating with a set of materials or solutions with known concentrations, the UV-Vis-NIR spectra can be used to determine the concentration of an analyte in many unknown samples.
X-ray diffraction (XRD) is an analytical technique where you can determine average bulk composition, identify and quantify crystalline phases, as well as provide information on unit cell dimensions in a material. Our instruments work best with powder samples that have been finely ground and homogenized.
XRD gives you the means to understand your materials from the atomic and molecular level and has a wide variety of applications in biochemical, chemical, materials, and geochemical fields, and industries such as construction materials, minerals & mining, oil & gas, nanomaterials, pharmaceuticals, semiconductors, and much more.