Material Characterization

Chemical and physical testing of catalysts, powders and other materials provide necessary information for optimizing, troubleshooting or developing materials and catalysts. Environex’s material characterization provides benchmark measurements in comparison to commercial alternatives, determines optimal materials, identify problems, and quantify a material’s unique characteristics.

Environex’s full-service material testing laboratory perform tests on a per-sample basis or in a complete testing program based on the customers need.

Methods of Characterization:

Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS)more

Scanning Electron Microscopy (SEM) obtains 3D-like images at high magnifications for surface analysis and analysis of microscopic features using an analytical scanning electron microscope. When this microscopic particle analysis is coupled with Energy Dispersive Spectroscopy (EDS), elements are identified and their concentrations measured within the analyzed area which can range from submicrons to millimeters.

Energy Dispersive Spectroscopy (EDS) plot

Electron Spectroscopy for Chemical Analysis (ESCA)more

Electron Spectroscopy for Chemical Analysis (ESCA) plot

Electron Spectroscopy for Chemical Analysis (ESCA) also known as X-Ray Photoelectron Spectroscopy (XPS) characterizes surface chemistry (the top 20-30Å of the sample) for all elements with the exception of hydrogen and helium. Concentration depth profiles can characterize the sample’s concentration as a function of depth. ESCA can also provide information about an element’s oxidation state which affects an atom’s binding strength.

Inductively Coupled Plasma Mass Spectroscopy (ICP-MS)more

Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) results

Inductively Coupled Plasma Mass Spectroscopy measures concentrations of multiple trace elements down to, and sometimes below, the ppt level depending on the instrumental detection limit. ICP-MS can be used to analyze liquid or solid samples. ICP-MS is capable of analyzing complex matrices with little interference due to the high temperatures of inductively coupled plasma.

BET Surface Areamore

BET surface area analysis is a physiosorption method using gas adsorption isotherms to calculate the surface area of a material. The adsorption isotherm measures the quantity of gas adsorbed by the solid at a constant temperature as a function of relative pressure. Using the BET theory, the surface area of the material is calculated. Both single and multipoint BET surface are methods can be used to determine the surface area of the material. Surface area can be used to monitor a material’s solubility, absorptive capacity, catalytic activity and stability.

Pore Size Volume (PSV)more

Pore Size Volume and Pore Size Distribution plot

Pore size volume analysis uses BJH adsorption and desorption isotherms, Langmuir isotherms, and t-plots to determine a material’s overall porosity (nonporous or porous), pore types (open pores, closed pores) and size (macropores, mesopores, micropores). Pore size and BJH pore volume are important characteristics relating to the material’s solubility, absorptive capacity, catalytic activity, stability, chemical reactivity of solids and the physical interaction of solids with liquids and gases.

Thermogravimetric Analysis (TGA)/ Differential Scanning Calorimetry (DSC)more

Thermogravimetric Analysis (TGA) measures the change in mass as a function of temperature. Differential Scanning Calorimetry (DSC) measures the rate and degree of heat change as a function of time or temperature. By combining these two analyses (TGA-DSC), the following thermal properties can be measured: temperature and heat of fusion, vaporization and crystallization, heat of reaction, temperature and heat of decomposition, heat of solution, specific heat, activation energy, polymer crystallinity, curing time, material purity, thermal and oxidative stability, material purity, thermal and oxidative stability, reactivity and reaction rates.

Differential Scanning Calorimetry (DSC) plot

Temperature Programmed Reduction (TPR)/ Oxygen Storage Capacity (OSC)more

Temperature Programmed Reduction (TPR) and Oxygen Storage Capacity (OSC)

Temperature Programmed Reduction (TPR) analysis is a chemisorption method which determines the temperatures needed for complete reduction of a material using hydrogen as the reducing gas. The consumption of hydrogen is measured as a function of temperature and time. The area under the TPR curve represents the total hydrogen consumed. This area is used to calculate the oxygen storage capacity of the material. Oxygen storage capacity is an important parameter for developing oxidation catalysts for oxygen limited reactions, such as TWC catalyst for automobile exhaust treatment. Common oxygen storage materials include cerium oxide powder, zirconium oxide powder, and other mixed rare earth oxides.

Particle Size Distribution (PSD)more

Mean particle sizes and particle size distribution are measured using laser diffraction in a wet dispersion. Particle sizes can be measured between 0.3 µm to 300 µm. Particle size analysis is important for efficient use and selection of raw materials, monitoring and optimizing in-process materials and characterizing final products.

Adhesion Testingmore

Coated materials are tested for adhesion using mechanical stress and ultrasonic techniques. Adhesion testing results can be used to optimize particle size of the coating, optimize coating formulation and refine the coating technique.

Environex, Inc.