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Title: Development of polymer-clay nanocomposite conformal coatings for tin whisker mitigation
Author: Pearson, Helen E.
ISNI:       0000 0004 7970 9249
Awarding Body: Loughborough University
Current Institution: Loughborough University
Date of Award: 2018
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Whiskers are electrically conductive crystalline eruptions, which may spontaneously grow from metallic surfaces. Whisker growth, more specifically filamentary tin whisker growth, presents reliability issues for the electronics industry due to their ability to bridge small gaps between components and other conducting parts of an electrical device, thereby causing a short circuit. Even if complete failure is avoided, tin whisker growth can compromise the reliability, longevity and functionality of an electrical device. A number of mitigation strategies have been proposed to reduce the risk of reliability issues for the electronics industry such as the application of a conformal coating. Conventional conformal coatings, which are often applied to electronic devices to protect against unfavourable environmental conditions and extreme temperatures are not designed to mitigate whisker growth. They have been shown to impede tin whisker growth by containment within the coating, but more commonly they pierce and protrude through the coating, thereby presenting a shorting risk. This research objective is to impede or prevent tin whisker growth, by the application of a modified conformal coating to the surface of the conducting metal. A high modulus reinforcing phase has been incorporated into a polymer matrix, to carry the majority of force exerted from any applied load or external stress (i.e. whisker growth), thereby improving the mechanical properties in the modified material. Dynamic mechanical analysis of the modified coating revealed an increase in storage modulus, whilst tensile testing highlighted an improvement in properties. Furthermore, whisker growth studies of the modified coating have demonstrated an improved resistance to whisker growth. A patent application (GB 1504551.1 and PCT) has been filed in respect of this research. Nanocomposite materials with improved mechanical properties and improved whisker mitigating properties have been successfully prepared, whilst maintaining the standard physical properties required in a conformal coating.
Supervisor: Not available Sponsor: Loughborough University
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Materials Engineering not elsewhere classified ; Tin ; Whisker ; Nanocomposite ; Coating ; Polymer ; Acrylic ; Urethane ; Organoclay ; Nanoclay ; Conformal ; Mitigation ; Modified ; Electronics