Lead-free solder: A train wreck in the making

John Keller, Editor in Chief

Click here to enlarge image

A slow-motion train wreck in military and aerospace electronics design is taking place right in front of us. Everyone seems powerless to do anything to head off the catastrophe, yet no one can tear his eyes away from the impending crash that we all know is virtually certain to happen.

The wreck-in-progress revolves around the evolving switch in the electronics industries in the U.S., Europe, and throughout the world from conventional lead solders to the new lead-free solders.

The specific threat is tin whiskers, which are physical abnormalities that grow in nonlead solders that lead to unpredictable shorting and failures of electronic parts. This phenomenon will compromise the reliability and reputation of most, if not all, commercial off-the-shelf (COTS) electronic parts and subsystems.

The move to nonlead solders stems from the Reduction of Hazardous Substances rules-better known as RoHS-that will apply to electronic products sold in Europe as of next July.

What that means is no one who wants to sell into the lucrative European electronics market will continue using leaded solders on a large-scale basis. The electronics industry throughout the world is starting to default to nonlead solders in the interests of maintaining business in Europe.

What we see happening now with lead solders is similar to what we saw a decade or more ago with military-specific integrated-circuit fabrication. The military’s share of the electronics market relentlessly shrank, the Defense Department’s COTS edict was issued, and integrated-circuit companies no longer had any incentive to produce military-grade devices.

One-by-one, the military chip lines closed, except for the rare small boutique fab. Everyone else went commercial because that’s where the money was.

Those in the military and the defense industry, of course, sought to keep the military IC industrial base intact through a series of weak, half-hearted measures, but ultimately the chip companies followed the money, and who could blame them?

Military officials then were living in a past in which the military was the largest consumer of electronic components and could call the shots in industry. It was a rude awakening to them when military chip lines folded up their tents with barely a glance behind them.

It looks like the military and defense industry failed to learn the lesson then, because the same thing is happening now with leaded solder. Companies are walking away from leaded solders because they see their economic futures elsewhere, driven primarily by the European program to limit the use of lead.

So where does this leave the military-particularly high-reliability, life- and mission-critical systems such as missiles, navigation systems, aircraft avionics, and communications satellites?

Where this trend places the military, at least in the short term, is in a lot of trouble.

The industry-accepted alternative to leaded solders is lead-free tin as a final finish, which spontaneously can sprout single crystal hair-like growths-the so-called “tin whiskers.”

These growths are electrically conductive, can grow in days or years, and can easily bridge between contacts, can touch each other to cause electrical problems, and can break off to bridge board traces and foul optics.

Although there are some programs that are starting to address the problem, the military now has no effective and accepted tests to determine the susceptibility of platings to whiskering, and no mitigation technique guarantees the protection that the Defense Department requires for high-reliability systems except the addition of 3 percent or more lead to the tin.

In addition, no quantifiable means of predicting tin-whisker-related problems exist. In short, there is no one solution for all tin plate applications.

Eventually, scientists and engineers will come up with ways to mitigate the forming and the effects of tin whiskers, but the electronics industry isn’t waiting. Nonlead solders are already in the marketplace, and military leaders are already seeing tin-whisker-related system failures.

The U.S. Naval Air Warfare Center (NAWC) at China Lake, Calif., for example, supports about 20 air- and surface-launched weapons, such as the Tomahawk cruise missile, Sidewinder air-to-air missile, and Joint Direct Attack Munition (JDAM).

Of those weapons programs, NAWC officials report that five-that’s 25 percent, mind you-built from 1985 to 1992 have had documented tin-whisker failures.

Reports indicate that six satellites sustained partial or complete loss due to tin whiskers. These involved Galaxy-3, Solidaridad 1, Direct TV3, and HS 601 satellites built between 1998 and 2002. Problems also have been reported with the F-15 jet fighter radar, the Patriot missile, and the Airborne Warning and Control System (AWACS) aircraft.

The period during which those systems were built was just the beginning of the semiconductor industry shift to pure tin solders. We ain’t seen nothin’ yet.

It’s probably going to take a lot more failures-some likely involving more than a few human deaths-before this issue gets the attention it deserves.

In some corners of the military, officials are trying to come to grips with this problem. Near-term attempts to date, however, promise to be ineffective. Most military leaders are simply ignoring the problem and hoping it goes away.

The U.S. Defense Logistics Agency, for example, has provided a sample list of defense specifications that preclude the use of pure tin. These include MIL-PRF-38535 paragraph A., MIL-PRF-55182 paragraph, MIL-PRF-55342 paragraph 3.5.3, and several others.

These days, however, trying to control private industry by issuing a series of government specifications is a lot like herding cats or teaching a pig to sing; it wastes your time, and only annoys the animals.

Last May officials of the Air Force Aeronautical Systems Center at Wright-Patterson Air Force Base, Ohio, issued Airworthiness Advisory AA-05-01, Lead-Free Solder. The directive points out what most in industry already know about the problems and systems failures that tin whiskers threaten.

The advisory concludes with this guidance: “Though there are many alternative solder alloys available to replace traditional tin-lead, none of them has passed the reliability testing required of aerospace-quality hardware.”

The directive continues, “Until such a time that a suitable, reliable, lead-free solder replacement is identified, all program managers should ensure their electronic equipment suppliers continue to provide items which meet all performance, compatibility, and reliability requirements. Failure to do so could adversely affect the reliability of weapons systems.”

You hear that, all you program managers? It’s your job to keep industry from switching away from leaded solders.

Before you do that, a word of advice: make sure you know what songs that pig likes best.

Get All the Military Aerospace Electronics News Delivered to Your Inbox or Your Mailbox

Subscribe to Military Aerospace Electronics Magazine or email newsletter today at no cost and receive the latest information on:

  • C4ISR
  • Cyber Security
  • Embedded Computing
  • Unmanned Vehicles

Get All the Military Aerospace Electronics News Delivered to Your Inbox or Your Mailbox

Subscribe to Military Aerospace Electronics Magazine or email newsletter today at no cost and receive the latest information on:

  • C4ISR
  • Cyber Security
  • Embedded Computing
  • Unmanned Vehicles

Military & Aerospace Photos

Most Popular Articles

Related Products

XCalibur5090 | Dual Virtex-7 Based Digital Signal Processing 6U LRM FPGA with Quad 2500 MSPS DAC and 3200 MSPS ADC

The XCalibur5090 is a high-performance, reconfigurable, conduction-cooled 6U LRM module based on ...

Round Dome Light - NVIS

Blue Wolf’s NVIS MIL-STD-3009 Dome light is designed for cabin illumination or cargo areas. It ha...

XCalibur1645 | Freescale Eight-Core P4080 Processor-Based Conduction-Cooled 6U VPX Module

The XCalibur1645 is a high-performance, 6U VPX, single board computer supporting Freescale QorIQ ...

Optical Switches

Multiport (N x M) Optical Switches from large core, multimode and Plastic Optical Fiber (POF) for...

Dual Mode NVIS 4 Inch Pod Light

Blue Wolf’s new DUAL Mode NVIS 4 inch pod lights is fully rotatable thru 320 degrees, can be fixe...

NVIS Gooseneck Map Light

NVIS MIL-STD-3009 White Gooseneck Map Light. 0 to 100% brightness control. Tactile feedback and ...

NVIS White Post Light Cap Insert

Blue Wolf’s MIL-STD-3009 Post Light cap inserts are specifically designed for illuminating instru...

NVIS White Utility Light

Blue Wolf’s NVIS MIL-STD-3009 Utility Lights is specifically designed for easy handling and spot ...

XPedite7574 | 5th Generation Intel® Core™ i7 Broadwell-H Processor-Based Conduction- or Air-Cooled 3U VPX-REDI Module

The XPedite7574 is a high-performance, 3U VPX-REDI, single board computer based on the 5th genera...


Telesis offers a broad range of laser marking solutions. By working with all major laser marking ...

Related Companies

LiquidCool Solutions

LiquidCool Solutions is a technology development firm with patents surrounding cooling electronics by total immersion...

Fibersense & Signals Inc

Develops and manufactures fiberoptic, optoelectronic, photonic and laser-related products for aerospace command and c...

Blue Wolf

Blue Wolf has been designing Night Vision (NVIS) LED lighting products for Government and Commercial vehicles since 2...


Is a mechanical engineering consulting company headquartered in Los Angeles, CA with operations in Billerica, MA, pro...

Curtiss-Wright Defense Solutions

About Curtiss-Wright Defense Solutions Curtiss-Wright Defense Solutions (CWDS) is a long established techno...

Telesis Technologies Inc

Specializes in product identification and processing technologies. Provides a range of permanent and programmable DPS...


Mil Spec EMC/NEMP/ filters and EMC product solutions for military applications.

Southwest Antennas

Southwest Antennas designs and manufactures high-performance RF & Microwave antennas and accessories designed for tod...


ISVI designs, produces and sells machine-vision camera systems combining high-speed and high-resolution sensors with ...

Premier Polymers

Provides seamless epoxy flooring and industrial resinous coatings


Harsh Environment Protection for Advanced Electronics and Components

This webinar will offer an opportunity to learn more about ultra-thin Parylene conformal coatings – how they are applied, applications they protect today, and the properties and benefits they offer, includin...

New Design Tools That Help You Develop Radar That Sees the Un-seeable and Detects the Undetectable

Xilinx EW/ISR System Architect, Luke Miller, has new tricks and he’s going to tell you all about them in a new Xilinx Webinar—for free. His Webinar will cover new ways to implement Radar functions including ...
Sponsored by:

Press Releases


Curtiss-Wright Corporation today announced that its Defense Solutions division has received a contract from Sierra Nevada Corporation (SNC) to supply its small form factor ...

Innovative Integration Announces the FMC-Servo

Camarillo, CA June 19, 2015, Innovative Integration, a trusted supplier of signal processing and data acquisition hardware and software solutions, today announced the FMC-S...


Curtiss-Wright Corporation today announced that its Defense Solutions division has further enhanced its innovative VRD1 high definition (HD) video management system (VMS) w...

All Access Sponsors

Mil & Aero Magazine

August 2015
Volume 26, Issue 8

Download Our Apps




Follow Us On...


Military & Aerospace Electronics

Weekly newsletter covering technical content, breaking news and product information

Cyber Security

Monthly newsletter covering cyber warfare, cyber security, information warfare, and information security technologies, products, contracts, and procurement opportunities

Defense Executive

Monthly newsletter covering business news and strategic insights for executive managers

Electronic Warfare

Quarterly newsletter covering technologies and applications in electronic warfare, cyber warfare, optical warfare, and spectrum warfare.

Embedded Computing Report

Monthly newsletter covering news on embedded computing in aerospace, defense and industrial-rugged applications

Unmanned Vehicles

Monthly newsletter covering news updates for designers of unmanned vehicles