PRACTICE GUIDE ON PARTICLE SIZE CHARACTERIZATION NOW AVAILABLE.

The first in a new publication series, the NIST Recommended Practice Guide: Particle Size Characterization, will help industrial and academic laboratories measure particle size and size distribution of ceramic powders in a more reliable and reproducible way. Improper powder size measurements during processing can affect the mechanical, electrical or thermal properties of the final product, resulting in poor quality and high rejection rates. Designed for a general user, the guide includes aspects of particle characterization research conducted by NIST for well over a decade. This research also has resulted in the development of standard reference materials and improvements in measurement procedures.

The guide covers techniques commonly used in the ceramics manufacturing industry such as microscopy, sieving, gravitational sedimentation and laser light diffraction. For each technique, the book provides (directions for sample preparation, instrument calibration and set-up; details relevant national and international standards; and discusses capabilities, limitations and general principles.

NIST researchers are looking at the challenges presented in the characterization of smaller-size (sub-micrometer or nanometer) particles. These powders typically are used in the manufacture of components, such as substrates for computer chips and high-temperature structural materials. NIST plans to hold a workshop issues related to reliable particle size measurement at the sub-micrometer and finer levels in October 2001.

To obtain a copy of NIST Special Publication 960-1, NIST Recommended Practice Guide: Particle Size Characterization, contact Carolyn Sladic, [phone], [e-mail].