The Influence of Particle Size and Shape on Flow Properties

The size and shape of the particles within a powder are important factors in influencing behaviour, and many well-established techniques exist for measuring these properties. However, over a range of different processes, the relationship between these two parameters and flow properties is less well-understood, and due to the varying demands powders are subjected to by […]

Expanding the Material Characterization “Toolbox” for Excipient and Active Pharmaceutical Ingredient (API) Vendor Qualification

Physical characterization of pharmaceutical excipients is not only a requirement but can also provide data that can be predictive in nature regarding the performance of final dosage forms including tablets, capsules, inhaled dosage forms, transdermals, and others. Manufacturers generally provide some of this physical testing data, such as particle size. In the case of particle […]

Particle Size Determination of Porous Powders Using the SediGraph

Sedimentation analysis based upon Stokes’ Law provides a convenient method for determining particle size distribution (PSD). A single solid (or nonporous) sphere settling in a fluid has a terminal settling velocity which is uniquely related to its diameter. The SediGraph determines particle size distributions using the sedimentation method. By measuring the gravity-induced settling velocities of […]

Suspending Fluid Viscosity Requirements for Gravity Sedimentation Particle Size Analysis

The Micromeritics SediGraph is designed to provide particle size distribution analyses for materials based upon sedimentation of the particles through a liquid of known viscosity and density. Stokes’ Law is used to determine the equivalent spherical diameter of the settling particle from its terminal velocity or sedimentation velocity, v. The velocity is based upon the […]

Free Space Determination with Non-Helium Gases

Free space is conventionally measured using helium because it is nonadsorbing and does not condense at cryogenic temperatures. Helium is, however, relatively scarce on Earth and comes with a high price tag due to its limited availability and the costs associated with its extraction and purification. Despite its rarity, helium is widely used in scientific, […]

The Mayer-Stowe Method for Determining Particle Size Using the AutoPore IV Series Porosimeters Theoretical

Theoretical models of mercury intrusion mechanisms allow information about particle size to be extracted. These models are included in the AutoPore IV Series data reduction package. In 1965, Mayer and Stowe* published a paper on the mercury breakthrough pressure required to penetrate a bed of packed spheres and the subsequent filling of the interstitial void. […]

The Particle Size Paradox

Is there a single best particle size technique? Particle size provides important information for research and development, quality control, and quality assurance as well as understanding the small physical details in a milling or powder compaction process. Different analytical techniques seldom provide the same value for particle size. The “paradox” of particle sizing is that […]

TPR of Copper Oxide Nanoparticles on Alumina – Understanding the Effects of Particle Size and Surface Chemistry

Temperature programmed reduction (TPR) is often used to characterize the reducibility of metal oxides. It is a fingerprint of the reduction of the material as a function of temperature. The peak areas and max peak temperatures gives information on the strength, heterogeneity, and quantity of the reducible species. TPR studies are often repeatable, but a […]

Physical Characterization Methods for Cathode Powders

Anytime a powder is used in a process for a specific purpose, its behavior is often predicted by physical properties of the powder.  Determining the physical properties of a cathode powder can be used to decide which properties are critical to the performance of the cathode, as well as the battery in which it is used.  A sample of lithium iron phosphate (LFP) powder was characterized to determine […]

SAS

Fully automated replacement for the Fisher Model 95 Sub-Sieve Sizer (FSSS) for particle size, surface area, and powder bed porosity