In a message dated 96-10-20 18:06:19 EDT, you write: << One of our customers recently asked " Is there any correlation between Ionic contamination testing (SEC) and surface insulation resistance testing?" It has been my understanding that the tests probably reflect many of the same contaminants but that there may be some not detected by one or the other test. Is this impression true? If so, what types of contamination may not be detected? >> Yes and No. A definite maybe. Sort of. The correlation now is a loose one at best. In general, as ionic residues rise, SIR will degrade. How much degradation depends on the ionic species involved and the amounts. SEC testing will tell you if you have a material which is conductive in solution, but not what the composition is, or if the materials are detrimental. Some elements, such as weak organic acids, will show high levels in an SEC test, but are benign insulators on a board surface. The link becomes much better between ionic data as measured by ion chromatography (IPC-TM-650, method 2.3.28) and SIR testing. Another factor is the SIR test profile used - static, cyclic low temp, high temp, etc. An SEC test will not detect a polyglycol material, which can degrade SIR. SEC will not pick up the presence of non-ionic organic compounds, which can degrade SIR. Doug Pauls CSL Chair, SIR Task Group *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************