Click the links for each type of testing to see our specific capabilities.
Training & Use
To use any of the machines, you must either be trained by the lab manager or should have a lab operator assisting you. Please see our training information and user policies pages for more information.
“Macroscopic” refers to things that are visible to the naked eye. This is in contrast to microscopic, which magnifies objects to observe very small things. Macroscopic testing measures some type of bulk property (such as surface area or strength) rather than chemical properties.
Mechanical testing on a mechanical test frame (MTF) or universal testing machine (UTM) measures compression, flexure, and tensile properties of a material.
Compressive strength refers to an object’s ability to withstand downward forces which compress it. Compression is also used for hardness testing of materials.
Flexural strength or bend strength refers to an object’s ability to withstand downward loads which bend it while extending across a distance. This is accomplished with a three-point or a four-point bend test.
Tensile strength or ultimate tensile strength refers to an object’s ability to withstand pulling loads (an upward force) which lengthen it.
Surface Area Analysis
Several methods of surface area and pore analysis exist such as the Brunauer–Emmett–Teller (BET) method, Langmuir method, t-plot, Barrett-Joyner-Halenda (BJH) method, Dubinin method, and the micropore analysis (MP) method. Each uses the physical adsorption of gas molecules on a solid surface such as a powder or small rocks to measure the specific surface area of materials.
Particle Size Analysis (PSA)
PSA is used to determine the size of powdered particles and is especially useful for determining the efficiency of milling techniques. The sample is suspended in a liquid matrix, and light passes through. The scattering of the light is used determine the approximate diameters (seen as a histogram) of the particles.
On a digital scale, mass is determined using a strain gauge that converts pressure into an electrical reading.
Thermal analysis is used to determine a material’s properties and reactions when it goes through a temperature change, or over time at a given temperature. It can give information about both the macroscopic and chemical properties of a material. It can be used to determine the thermodynamic and kinetic properties of materials.
Differential scanning calorimetry (DSC)
DSC measures the thermal properties of a material such as melting point (Tm), glass transition temperature (Tg), crystallization point (Tc), and heat capacity (Cp). It can additionally study liquid crystal (LC) phases and transitions or degree and rate of polymer cure.
Thermogravimetric analysis (TGA)
TGA is used to determine the mass or weight change of a material over time or temperature. It can be used to identify decomposition temperatures, oxidation temperatures, the kinetics of decomposition, thermal stability, and some phase transitions.
Dilatometry measures a material’s expansion as temperature increases. Dilatometry is very useful in determining a material’s coefficient of thermal expansion (CTE) and can indicate some phase transitions.
Optical microscopy uses visible light and a system of lenses to observe samples at up to several hundred times magnifications.
Metallography is the study of the physical structure and components of metals using microscopy. Samples are sometimes prepared by mounting in resin, then grinding, polishing, and sometimes etching with acid (see next section). The microstructure’s features can be observed: crystal grain boundaries, intermetallic layers, and crack formations. These features can help with failure analysis of materials, the success of certain processing techniques, and observing phase boundaries.
For certain types of analysis, samples are cross-sectioned to view internal features. Electronics assemblies and other items that are combinations of different types of materials can be cross-sectioned to verify structure and quality, as well as to help determine failure modes. Other sample preparation methods exist; choice of these methods is dependent on the intended characterization and the intrinsic materials properties. Some examples of necessary sample preparation methods are sputtering, grinding into a powder, pressing into a pellet, etc.
Sputtering uses a voltage difference across a solid target to deposit the atoms from that material to another material of choice. This can be done with gold (Au), carbon (C), palladium (Pd), silver (Ag) and alloys of these materials.
Most materials can be cross-sectioned with routing, sawing, or punching, but each method adds mechanical stress which can damage the area to be analyzed.
Small samples can be mounted in an acrylic or epoxy resin to facilitate the polishing process and ease of handling. The resin material is chosen based on cure time, shrinkage, adhesion to the sample, similar hardness to the sample, conductivity, and so on. A small vacuum can be used to remove air bubbles from the preparation.
Samples can be ground with finer and finer grits of grinding paper and then polished with a fine slurry until the desired location is visible and smooth. After a final polish, the sample can be examined with a metallographic microscope and/or scanning electron microscope (SEM).
SEM, similar to optical microscopy, magnifies small objects and materials. Instead of visible light, it uses a beam of focused electrons to view objects at magnifications of 15 to 60,000x. It allows micro- and nano-sized particles and anomalies to be measured and imaged.
Energy Dispersive Spectroscopy (EDS)
EDS can be done with SEM. It detects x-rays put off by the sample being imaged and measures the energy of each x-ray it detects. Each element has unique x-ray energies that create a fingerprint that is unique to the element in question. This is used for quantification analysis of materials, and can also be used to view phase or elemental separation within a sample.
Spectroscopy is the study and measurement of how an object interacts with or emits electromagnetic radiation (light).
Fourier Transform Infrared Spectroscopy (FT-IR)
FT-IR involves the absorption or transmission of infrared light. FT-IR spectra show peaks that correspond to vibrations (also called vibrational modes) between atoms that have a polar bond. It is most commonly used in polymer analysis, but can also be used to determine concentrations in gas and liquid solutions.
Ultraviolet-Visible-Near-Infrared Spectrophotometry (UV-Vis-NIR)
UV-Vis-NIR involves the absorption, reflection or transmission of UV, visible, and near-infrared light. It can be used to determine the efficiency of solar cells and other semiconductors. After calibrating with a set of materials or solutions with known concentrations, the UV-Vis-NIR spectra can be used to determine a solution’s concentration.
X-ray diffraction (XRD) is an analytical technique used to identify and quantify crystalline phases, as well as provide information on unit cell dimensions in a material. It is commonly used in powder analysis for phase and alloy structures.