NASA Goddard Space Flight Center

Electromagnetic Relay Manufacturer Survey

The following information was obtained by Goddard Space Flight Center (GSFC) through a Nov./Dec. 1998 telephone survey of various electromagnetic relay manufacturers in the United States. This information is provided for general guidance to assist GSFC programs in determining the likelihood that relays used in their designs may have pure tin plating.  In addition, (when available) residual relays have been analyzed using EDAX to determine the constituent materials in the plating.



Question 1

Has pure tin plating ever been used on Military Spec. parts?

Question 2

What kind of plating is used currently?

Question 3

Is pure tin used for commercial product?

Question 4

Does the manufacturer report any field experience with tin whiskers?

GSFC EDAX Evaluation

Examination of Residual Parts at GSFC



No pure tin for last 10 years ~4% Lead (Pb) added to Tin (Sn) No. None known.  No samples evaluated.
Communications Instruments, Inc. 


No pure tin for last 15 to 20 years ~5% Lead (Pb) added to Tin (Sn) No. Same process for Military and commercial. None known for at least 15 years. No samples evaluated.
Deutsch So far unable to locate information So far unable to locate information So far unable to locate information So far unable to locate information No samples evaluated.
Electronic Specialty Corp.


No pure tin since the 1980ís when pure tin was prohibited ~5% Lead (Pb) added to Tin (Sn) Yes. External only. None reported, but the manufacturer is aware of tin whisker phenomenon. No samples evaluated.
(acquired by CII in Dec. 1997)


No pure tin for last 15 to 20 years Eutectic Tin/Lead (Sn/Pb) No. Same process for Military and Commercial No problems since POC joined company. 2 part lots tested. Tin Alloys were used on both:
Hartman Yes.  Pure tin was used internally only Typical plating materials are Nickel (Ni) and Silver (Ag)  Yes. Same process for Military and Commercial.  Tin plating per MIL-T-10727  No.  1 part lot tested. Tin alloy used.
Hi-G Corp. No pure tin for last 25 to 30 years 60/40 Tin/Lead (Sn/Pb) No. No tin whisker problems, but point of contact is aware of phenomenon. No samples evaluated
Leach Corp.


Pure tin was used until 11/97 3% to 10% Lead (Pb) added to Tin (Sn) No. Yes. 15 part lots evaluated. 8 with LDCs ranging from 7920 to 9332 use pure tin including some S311 parts. The other 7 lots use Nickel, Nickel/Tin or Tin-Lead (LDCs from 9421 to 9832). Note: Leach has informed GSFC that pure tin was commonly used on product manufactured until 11/97.


Magnecraft purchased Struthers Dunn in 1995. Prior to the merger, Struthers Dunn product used pure tin plating on MIL-R-6106 relays. The combined company (MSD) does not use pure tin. Current MSD product uses ~7% Lead (Pb) added to Tin (Sn). Some Zinc (Zn) and Nickel (Ni) plated product is also offered. No. Most product is Tin/Lead plated. Yes. When Struthers Dunn was a separate company from MSD, they observed some rare occurrences of tin whiskers. 1 Struthers Dunn part lot M6106/50-006 with LDC 9309 has pure tin.

This part pre-dates Magnecraft buyout of Struthers Dunn and is strictly a Struthers Dunn product.

Potter & Brumfield (Siemens) No more military products being built.  Some products use 80/20 or 78/22 Tin/Lead Yes, pure tin is still used on some terminal sockets. Yes, about 20 years ago, some relay types were scrapped due to tin whiskers.  And of course, GIDEP Problem Advisory F3-P-97-01 was issued in 1996 covering whisker problems with P & B relays. No samples evaluated.


Teledyne has never used pure tin N/A No. No. No samples evaluated.

Responsible NASA Officials:

   Michael Sampson/NASA GSFC Code 306
   Dr. Henning Leidecker/NASA GSFC Code 562
Additional Researchers: 

   Jong Kadesch/Orbital Sciences Corp.
   Jay Brusse/QSS Group, Inc.

Last Updated:

April 20, 2005

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