“Investigation of power failure of a heating device operated in a Differential Scanning Calorimeter (DSC)”, Engineering Failure Analysis, Vol. 55 (2015), 360-369.
E. Spiropoulou, J. Brown, G. Pantazopoulos, D. Voulgaris
Abstract
The failure analysis of a heating device operated in a differential scanning
calorimeter (DSC) is presented in this study. Preliminary visual examination, after
instrument disassembly, revealed that device malfunction resulted from circuit
interruption due to platinum (Pt) ribbon rupture, while a corroded copper (Cu) base
connected to the Pt current leads was also identified. The tip of the ribbon has a
twisted shape ending with a molten area, where a solidified grain structure was
evident. A relatively coarse grain structure “pattern” has also been identified,
beyond the melted fractured area, suggesting the occurrence of localized
overheating. Transverse edge defects, located close to the fracture area are
identified as stress raisers and constitute potential evidence of fatigue crack
initiation sites. It can be postulated that the collected evidence support the
hypothesis of thermo-mechanical fatigue as the plausible damage mechanism.
Visual examination by means of optical Stereo-microscopy together with Scanning
Electron Microscopy coupled with Energy Dispersive X-ray Spectrometry for
elemental microanalysis were used as the principal analytical techniques for the
present investigation.