PHILADELPHIA—Stockwell Elastomerics, Inc., is producing EMI shielding gaskets and sheet materials with nickel-coated aluminum particles that are reported to provide long-term shielding effectiveness in harsh environments. The electrically conductive gaskets provide galvanic protection of electrical housings installed in marine environments and similar harsh environments, the company said in a release.
End users can select from two compounds—SNA-568 nickel-aluminum filled silicone and SNAF-572 nickel-aluminum filled fluorosilicone—that were developed by Specialty Silicone Products, Inc. (SSP). Both compounds are available to end-users through Stockwell Elastomerics as die cut gaskets, waterjet cut gaskets, and compression molded gaskets.
The die cut gaskets and waterjet cut gaskets are available in a range of thickness, from 0.020-inch thick to 0.125-inch thick. Compression molded gaskets can be custom molded from uncured compound if sealing beads or similar design features will benefit the performance of the housing, according to the release.
The SNA-568 nickel-aluminum filled silicone is 68 durometer Shore A and is said to perform in most applications that need long-term EMI shielding and galvanic corrosion resistance. The SNAF-572 nickel-aluminum filled fluorosilicone is 72 durometer Shore A. Fluorosilicone rubber provides enhanced resistance to swelling and deterioration when in contact with oils, fuels, and fluids used in aviation.
Fabricated gaskets can be provided with an electrically conductive acrylic or conductive silicone pressure sensitive adhesive to serve as an assembly aid.
“This family of nickel-coated aluminum-filled EMI gasket materials is offered for long-term shielding effectiveness and galvanic corrosion resistance in harsh environments,” said Stockwell Elastomerics President Bill Stockwell, in the release. “Further, the nickel-coated aluminum fillers should provide more cost stability in a time when the costs for traditional silver filled elastomers are volatile due to rising silver prices.”
The nickel-aluminum filled gasket materials are dark gray and have a smooth surface in comparison to nickel-graphite filled elastomers. SNA-568 was tested for galvanic corrosion according to ASTM B117 for saltwater spray, the company said.
Stockwell Elastomerics is a USA-based gasket and rubber fabricator with on-site rubber molding capabilities. To design gaskets that can seal effectively with lower closure force, sealing beads can be incorporated into the tool design and compression molded from a machined steel mold, the company said.