Materials Characterization

• X-Ray Fluorescence (XRF) is an analytical technique that can be used to determine what elements are present, but not how they are put together.
• XRF chemical analysis typically involves the determination of SiO₂, Al₂O₃, Fe₂O₃, TiO₂, MgO, Na₂O, K₂O, CaO, MnO, P₂O₅ plus Loss on Ignition.
• In XRF, x-rays are used to irradiate the sample. The elements present in the sample will emit fluorescent x-ray radiation with discrete energies that are characteristic of those elements. A different energy is equivalent to a different color. By measuring the energy, it is possible to determine which elements are present. By measuring the intensity of the emitted energies, it is possible to determine how much of each element is present.
• Coming Soon – Fall 2024 with expanded capabilities – Rigaku ZSC Primus III Next Sequential WD-XRF Spectrophotometer.
• Loss on Ignition (LOI) is performed using a muffle furnace and heating the sample to specified temperatures and measuring the change in mass. It is used to estimate the quantity of light elements such as carbon, hydrogen and oxygen in a material (hydrogen and oxygen are from the amount of chemically bound water typically associated with clay minerals). The LOI is used in chemical analysis to account for the elements that the XRF can’t detect.

• XRD provides mineralogical information, crystalline phase identification and quantification. It provides information on how a material is assembled.
• XRD is an analytical technique that often works best when combined with XRF to give a full picture of a material’s composition.
• X-ray diffraction is based on constructive interference of x-rays and the crystalline structure of the sample. The conditions satisfy Bragg’s Law (nλ=2d sin θ) relating the wavelength of the electromagnetic radiation from the x-ray to the diffraction angle and the lattice spacing in the crystalline sample. The diffracted x-rays are then captured by a detector, processed and counted. The sample is scanned through a range of 2θ angles to collect all possible diffraction directions of the lattice structure. The diffraction peaks are converted to d-spacing allowing for mineral identification. This identification is possible because each mineral has a unique set of d-spacings and is achieved by comparing the patterns to a set of references using software.

• For materials that are <200 mesh (74µm), Laser Scattering is used for particle size analysis. A particle size analyzer measures the particle size distribution. Particle size distribution is calculated using the light intensity distribution pattern of scattered light that is generated from sample particles when a laser irradiates them. This is the most common particle size analysis method because it has excellent properties such as a wide measurement range, a short measurement time, and the ability to measure both wet and dry samples.
• For crude samples, Sieve Analysis is used. Sieve analysis consists of using a series of sieves, decreasing in size openings or mesh size, to separate or classify a sample by particle size. A representative weighed sample is added to the top sieve with the largest opening. Through mechanical shaking, the material is dispersed through smaller mesh openings until a stable mass is reached on each sieve in the stack. The amount remaining on each sieve is measured and calculated as a percentage by dividing the mass of the sample on each sieve by the mass of total sample.
• Results are combined to provide the total particle size distribution.

• Gradient Firing Test provides information about the effects of time on the physical properties of the material at different temperature setpoints. This test correlates with Cone Tests but uses a nine-chamber gradient kiln programmed at different temperature ranges corresponding to the requested cone temperature range.
• Gradient Firing Test includes shrinkage, water absorption, and weight loss.

Note — A top and bottom temperature range is required when requesting this test

• Dilatometry measures the length of change (expansion or shrinkage) on heating and cooling. As a sample is heated in a furnace, the expansion or shrinkage of the sample is measured by sensors through the use of a push rod.
• Dilatometry is used to observe the firing behavior of a material. It can also be used to identify firing temperature.
• It is used to study vitrification, quartz inversion, and thermal expansion.

• Carbon/Sulfur Analyzer measures the total carbon and sulfur content of a material using high temperature combustion in an induction furnace and infrared gas analysis. A sample is placed in a ceramic crucible with flux and induction heating is used to reach high temperatures. The gases released from this reaction are captured and detected by a non-dispersive infrared detector (NDIR). Each gas has its own characteristic infrared spectrum, and the intensities of the peaks determine the gas concentration.
• Carbon and sulfur analysis can be used for mass balance measurements to estimate emissions.
• This instrument can also be used to differentiate between organic carbon and carbonates or pyrite and sulfates in a material.

• Soluble salt measurements are used in the resolution of efflorescence complaints. These soluble salts are measured using Ion Chromatography. Ion Chromatography separates ions based on their interaction with a stationary phase (present as a resin column differing depending on anion or cation) and mobile phase. The speed at which an ion moves through the column depends on the ion’s affinity for that resin. The stronger the affinity, the slower the ion will move through the column. As the ion exists the column, its electrical conductivity is measured by a detector and plotted over time. The peak intensity provides the concentration of the ion of interest.
• Soluble Anions: Fluoride (F), Chloride (Cl), Bromide (Br), Nitrite (NO₂), Nitrate (NO₃), Sulfate (SO₄), Phosphate (PO₄)
• Soluble Cations: Lithium (Li), Sodium (Na), Ammonium (NH₄), Potassium (K), Magnesium (Mg), Calcium (Ca), Barium (Ba)

• Micro XRF is typically used for defect analysis. It is similar to Energy Dispersive X-ray Spectroscopy (EDS) analysis with SEM but it is able to analyze a much larger area.
• Micro XRF uses small spot micro X-ray fluorescence to provide information about composition and element distribution in non-homogeneous samples and requires minimal or no sample preparation. It uses the same principles as traditional XRF but focused on a smaller area.
• Micro-XRF allows for fast measurements of large areas, with high spatial resolution in short times. The individual element distributions can be visualized and extracted quickly. Fundamental parameter-based quantification allows for a quick assessment of the composition of the sample. Smart analysis of mapping allows for semi-quantitative analysis.

• SEM can be used to analyze the crystalline structure, surface topography, electrical behavior, and chemical composition of approximately 1 µm of the top part of a specimen with a magnification down to nanometer scale.
• SEM is used for observing a physical object by irradiating an electron beam (a narrow, focused stream of electrons) onto the object by detecting, for example, “secondary electrons” emitted from the object and “reflected electrons” emitted when the direction of travel of the irradiating electron beam travelling within the object varies.

• COMING SOON to IPA Labs! ICP-MS is an analytical technique used to determine trace metals in water or solid samples (after digestion).
• ICP-MS uses an argon plasma to convert a liquid sample into ions that are measured using a mass spectrometer. The ions are separated based on mass-to-charge ratio. ICP-MS can measure elements down to the parts per trillion level.