Electronics Assembly Knowledge, Vision & Wisdom
Hybrid Conformal Coatings for Mitigating Tin Whiskers
Hybrid Conformal Coatings for Mitigating Tin Whiskers
In this stydy, nanoparticles were functionalized to bind them to the polymer structure while avoiding the collection among the particles.
Materials Tech

Authored By:
Junghyun Cho, Suraj Maganty
Binghamton University (SUNY), Binghamton, NY, USA

Stephan J. Meschter
BAE Systems, Endicott, NY, USA

Dale Starkey, Mario Gomez, David G. Edwards
Henkel Electronic Materials LLC, Irvine, CA, USA

Abdullah Ekin, Kevin Elsken
Bayer MaterialScience LLC, Pittsburgh, PA, USA

Jason Keeping, Polina Snugovsky, Jeff Kennedy
Celestica Inc., Toronto, ON, Canada
,{url:'http://www.circuitinsight.com/videos/hybrid_conformal_coatings_mitigating_tin_whisker_growth.mp4'},{url:'http://www.circuitinsight.com/videos/programs_final.mp4'}], clip:{autoBuffering:true, autoPlay:true, scaling:'scale' } }).ipad();
Summary
A conformal coating of polyurethane (PU) consisting of hard and soft segments is being studied in an effort to prevent tin whisker penetration. For this, the coating needs to possess optimum mechanical properties by providing sufficient strength, modulus, and hardness while maintaining good ductility and toughness.

Typical monolithic PU films, however, do not possess all these required properties, so silica nanoparticles are incorporated into a PU film to improve its whisker mitigation effectiveness. In the present work, nanoparticles were functionalized to bind them to the polymer structure while avoiding the agglomeration among the particles.

Selection of the ideal concentration of nanoparticles is determined by establishing microstructure-property relations. Structural features at different length scales are characterized by various instruments including atomic force microscope (AFM) and scanning electron microscope (SEM) while mechanical properties are evaluated via macroscopic tensile testing as well as nanoindentation.

In particular, the nanoindentation testing emulates the whisker penetration behavior by producing local deformation of PU around an indenter tip.
Conclusions
Functionalized nanosilica particles approximately 20 nm in diameter were added to a PU coating in an attempt to attain its optimum mechanical properties for mitigating tin whisker growth. It was shown that mechanical properties do not continuously increase with the nanosilica concentration.

This was due to non-uniform distribution of nanosilica and polymer structure change with added nanoparticles. Phase separation also seemed to be affected by the presence of nanosilica. In particular, microdefects created during film processing are responsible for film brittleness and limited ductility.

Establishment of the structure - property relationship is essential to identify optimal microstructures of the nanoparticle-filled PU, which can be of importance in tin whisker mitigation.
Initially Published in the SMTA Proceedings
Submit A Comment

Comments are reviewed prior to posting. Please avoid discussion of pricing or recommendations for specific products. You must include your full name to have your comments posted. We will not post your email address.

Your Name


Company


E-mail


Country


Comments


Authentication

Please type the number displayed into the box. If you receive an error, you may need to refresh the page and resubmit the information.



Related Programs
bullet How To Verify Cleanliness After Rework and Prior to Re-coating?
bullet SMT Adhesive Inspection
bullet Signal Loss in a High Speed High Frequency Transmission Line
bullet Exposed Leads on Conformally Coated Boards
bullet Un-cleaned PCB Assemblies Potted
bullet Dewetting of Acrylic Conformal Coating
bullet Conformal Coating for Tin Whisker Management
bullet Conformal Coating over No Clean Flux
bullet Aerosol Jet Printing of Conductive Epoxy for 3D
bullet Hybrid Conformal Coatings for Mitigating Tin Whiskers
More Related Programs
About | Advertising | Contact | Directory | Directory Search | Directory Submit | Privacy | Programs | Program Search | Sponsorship | Subscribe | Terms

Circuit Insight
6 Liberty Square #2040, Boston MA 02109 USA

Jeff Ferry, Publisher | Ken Cavallaro, Editor/Business Manager

Copyright © Circuitnet LLC. All rights reserved.
A Circuitnet Media Publication