Defects in molded silicone medical part identified.This provider of independent chemical analysis, physical testing, and research and development received a molded silicone medical part that contained a small discoloration on the tip. Testing showed that the defect was composed of an alloy of cobalt, chromium and molybdenum molybdenum /mo·lyb·den·um/ (Mo) (mah-lib´di-num) a chemical element, at. no. 42. mo·lyb·de·num (m  -l b, embedded in a silicone matrix. This alloy was present in another process in the same manufacturing facility and contaminated the silicone part. In order to arrive at this conclusion, the company used two main analytical techniques to examine the defect region, including optical microscopy 1. The study of microscopes. 2. The use of microscopes. 3. Investigation by means of a microscope. 1. tending to become dispersed. 2. promoting dispersion. spectroscopy spec·tros·co·py (sp k-tr s k-p. Initially, the defect was viewed and documented using an optical microscope at 32x magnification. In order to characterize the defect region, scanning electron microscopy (SEM SEM - Search Engine Marketing SEM - Evangelical Seminary of Madrid SEM - Saccadic Eye Movement SEM - Scanning Electron Microscope SEM - Scanning Electron Microscopy SEM - Scheduled Event Management (Sprint) SEM - School of Economics and Management SEM - Schoolwide Enrichment Model SEM - Science and Engineering of Materials SEM - Search-Engine Marketing SEM - Secondary Emission Monitor SEM - Secure Ethernet Multiplexer) coupled with energy dispersive spectroscopy (EDS) was utilized. This analytical technique is said to be ideal for determining the presence of inorganic species, especially in very small spot sizes. SEM magnifies the region of interest, while EDS acquires spectra of the chemical elements present in the magnified section. One can also map the spatial location of the chemical elements that are detected. The sample was analyzed using the SEM. A reference spectrum was acquired of a silicone region where there were no defects. Silicon, oxygen and aluminum were detected. The presence of silicon and oxygen was generated from the silicone medical part, and aluminum may have derived from interference from the SEM vacuum chamber components or the sample mount. The defect region was then located under the SEM. Many small particles were embedded in the surface of the silicone. EDS analysis of a wide area of the defect region indicated the presence of silicon, oxygen, aluminum, cobalt, chromium and molybdenum. Next, one of the particles in the defect region was isolated for spot mode analysis. Spot mode EDS analysis allowed a spectrum to be obtained from a very specific location on a defect particle. High concentrations of cobalt, chromium and molybdenum were detected compared to the wide scan. In order to illustrate the spatial distribution of the elements in the defect region, elemental maps were acquired in the defect region. The elemental maps illustrate the spatial position of the chemical elements that were detected and relate directly to the SEM micrograph 1. an instrument used to record very minute movements by making a greatly magnified photograph of the minute motions of a diaphragm. 2. a photograph of a minute object or specimen as seen through a microscope. mi·cro·graph (m that was obtained prior to mapping. The maps show that the particle is composed of cobalt, chromium and molybdenum, and is embedded in a silicone matrix. The distribution of these three metals in the particle was consistent with an alloy of cobalt, chromium and molybdenum. Polymer Solutions Circle 8 on card |
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