Analyzing Contaminants, Stains and Debris – Part 1

Rob — Fri, 02 Jul 2010 16:54:56 +0000

The impact of contaminants, stains or debris can range from nuisance to root cause of catastrophic failure. The nature of these materials presents some special analytical challenges. First, only extremely small amounts of material are usually present and available for analysis. Second, they typically result from an unintended and therefore undocumented variable in the manufacturing process or site, conditions encountered during shipping, or the service environment. This means the source can be a complete unknown, unrelated to any industrial use. Fingerprints, HVAC residue from filters or lubricants, insect excretions, road or sea salt which has found its way into “sealed” shipping containers, the almost microscopic remains of lunch sticking to an assemblers fingertips, combustion residue from nearby idling trucks, power plant smoke stacks or food processors, that “special” can of spray lube an employee keeps in his tool box. The list is literally endless, you are starting from square one, anything is possible and there is no such thing as “typical”.

The objective in analyzing contaminants is the identification and elimination or isolation of their source. Techniques used make this identification include Optical Stereomicroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS). The accompanying case studies describe a selection of contaminant investigation and analyses performed here at Metallurgical Associates. Part 2 of this discussion will describe examples of the analysis of contaminants for a variety of sources.

Read part 2 of Analyzing Contaminants, Stains and Debris.

Failure Analysis » stains

Analyzing Contaminants, Stains and Debris – Part 1