A Method for Cleaning Performance Evaluation Using Stable Isotopes.
Abstract
The Aerospace Guidance and Metrology Center (AGMC) at Newark Air Force Base (NAFB), Ohio, has been using cleaning agents such as 1,1,1-Trichloroethane (TCA) and 1,1,2- Trichloro 1,2,2-trifluoroethane (Freon 113) for repair of inertial guidance equipment. Both of these cleaning agents have been classified as stratospheric ozone layer depleting substance (OLDS). Therefore, AGMC is interested in replacing these with other cleaning agents such as aqueous detergents. In order to assure that reliability and maintainability levels are not degraded when OLDS are phased out, a method is required to validate that the cleaning capability of the suggested alternative is at least as good as that of an existing, proven cleaning agent. The current methods used by AGMC to evaluate cleanliness are not effective when the parts being cleaned are composed of irregular or severe geometrics as is the case for precision gyroscopes and accelerometers repaired at AGMC. Therefore, AGMC funded Battelle to develop and demonstrate a suitable procedure for quantifying cleanliness. This report describes a cleaning performance evaluation procedure (CPEP) based on the use of stable isotopes. The CPEP developed and demonstrated in this project involved two phases. In Phase I, the contaminants which are present in the current cleaning processes were identified to select synthetic inorganic particulate and organic contaminants. In Phase II, unique, stable-isotopes of these contaminants were introduced into the parts followed by cleaning of these parts with various cleaning agents. The amounts of these unique isotopes extracted, as determined by mass spectroscopy (MS) provides a measure of cleaning efficiency.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 1992
- Accession Number
- ADA308129
Entities
People
- J. C. Chuang
- P. Schumacher
- S. P. Chauhan
Organizations
- Battelle Memorial Institute