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Tin Whiskers Prevention Testing

Prevent Premature Product Failure with a Bruker Tin Whiskers Risk Detector Gun

NASA Tin Whiskers Image

Image Source: NASA

Tin whiskering is a common concern for many manufacturers, which can be ruled out with the help of A Bruker Handheld XRF analyzer. Message Bruker now for free expert advice on industrial tin whisker prevention, to schedule a demo, or for a prompt quote.

Screening for Tin WhiskersIn industries ranging from aerospace to defense to medical equipment manufacture, premature product failure caused by tin whiskers can have grave consequences. Tin whiskering results in the spontaneous growth of tiny needle- or tendril-like protrusions in electrical devices. These tin protrusions can then break loose or otherwise bridge electronic components, short-circuiting terminals and system boards and seriously crippling or even destroying whole systems. Where tin whiskers may be an issue, screening every relevant component before installation is a must. Verify component composition and help minimize the probability of tin whiskering with a Bruker S1 TITAN handheld XRF analyzer. This important precaution can potentially save manufacturers millions of dollars in potential development efforts and lost revenues. Use our contact form to get in touch today!

Tin Whiskers in More Detail

For reasons on which there is still no scientific consensus, tin whiskers tend to appear in manufactured devices where tin electroplating is used as a finish. These crystalline formations protrude out of a surface and can grow to several millimeters or even in some cases up to a full centimeter in length. Since tin whiskers are electrically conductive, they can cause short circuiting in devices by accidentally bridging adjacent electronic elements. Breaking off, tin whiskers can also damage optical devices.

Tin whiskers were first discovered in electronic equipment in the 1940s, during the vacuum tube stage of the electronics industry. Whiskering tended to occur in equipment that was manufactured with pure tin solder. Possibly due to compressive stress in components (as one theory states), small tin hairs that were forming between metal solder pads were causing annoying short circuits. (Whiskering is not unique to tin. Other types of metals subject to whiskering include zinc, silver, cadmium, indium, and lead.) Send us your query or tell us about your component screening needs!

Some Notorious Historical Examples

Here are some of the most notorious examples of equipment failure attributed tin whiskers. In 1998, the Galaxy IV telecommunications satellite was unexpectedly lost due to short circuiting. Conformal coating had been misapplied to the circuit boards at manufacture, allowing tin whiskers to emerge in the pure tin plating and to propagate through an uncoated area, thus disabling the main control computer. Galaxy IV’s manufacturer, Hughes, subsequently adopted nickel plating instead of tin in order to minimize whisker growth, although this practice causes a weight increase of 110-220 lb per payload.

In 2005, Connecticut’s Millstone Nuclear Power Plant had to be shut down because of a false alarm caused by a tin whisker that had short circuited the logic board responsible for steam pressure monitoring.

In 2011, three NASA investigators warned that the tin whiskers they had detected on the accelerator position sensors of sampled Toyota Camry models might have partially caused the “stuck accelerator” crashes of 2005-2011. (However, it should be noted that this conclusion contradicts Toyota’s claims and is at odds with the earlier 10-month joint investigation by the National Highway Traffic Safety Administration (NHTSA) and a large group of other NASA researchers, which found no issues with the electronics. As per Toyota’s official press release on the subject, “no data indicates that tin whiskers are more prone to occur in Toyota vehicles than any other vehicle in the marketplace,” and that “their systems are designed to reduce the risk that tin whiskers will form in the first place.” Yet the jury is out.)

Tin Whiskers Prevention

Equipment manufacturers have developed numerous ways of reducing the risk of whiskering, such as modifications to the annealing process (heating and cooling), copper and nickel admixtures, and conformal coatings (thin polymer films that conform to the contours of a printed circuit board, protecting the components).

The most common and technically reliable solution is simply to avoid the use of pure tin plating whenever possible. For example, the most common military specifications today prohibit pure tin plating, although with some exceptions. Alloying tin with another metal reduces the risk of whiskering. Originally, lead was added to tin-based solders to reduce and slow down tin whisker formation. An alloy of tin and of a minimum of 3% by weight of lead is effective for the purpose. Although this solution does not rule out tin whiskers completely, they turn out to be drastically smaller than those resulting from the use of pure tin plating and generally pose no risk in microelectronics.

Although this last method is still used, the European Union banned the use of lead in the majority of consumer electronic products from 2006 onward, owing to the health risks posed by lead and the “high-tech trash” problem. However, lead-free manufacturing is challenges for High Reliability (or “Hi-Rel”) industries, causing the following main problems:

  • Dangers resulting from the presence of high-purity tin (Sn), which leads to so-called “tin filamentary corrosion,” another name for massive tin whiskering.
  • Insufficient test data associated with innovative lead-free systems and components.
  • The lack of proper testing equipment. This is where Bruker™ comes to the rescue! Screening tin alloys with a Bruker gun for the presence of lead or other relevant non-tin inclusions helps prevent accidents.

Screening for pure tin (Sn), cadmium (Cd) or zinc (Zn) at the device manufacturing or buying stage has never been easier, thanks to the Bruker XRF handheld analyzers. These lightweight, cutting-edge S1 TITAN guns provide quick and accurate results, ensuring the integrity and consistency of alloys and thus preventing potentially disastrous, avoidable accidents. Contact Bruker now to speak with one of our knowledgeable team members about our product line and how you can increase the profitability of your business with advanced testing equipment.

Advantages of Using a Handheld Bruker XRF Analyzer

In a nutshell, Bruker’s lightweight portable analyzers, such as the S1 TITAN, are specifically designed to provide easy, flexible, nondestructive, fast, and reliable means of identifying exempt materials such as pure tin, cadmium or zinc which increases the potential for tin whiskers– thus “shaving the risk” of system failure. Ideal for on-site and in-lab testing! Contact a Bruker expert today to safeguard your investment and ensure product reliability and functioning with a state-of-the-art S1 TITAN! (Visit the product page for technical details).

Also consider these XRF Applications for Aerospace Alloys QAQC and Positive Material IdentificationScrap Metal IdentificationTin WhiskersFlow Accelerated Corrosion, and Component Analysis. Also pay our XRF Technology page a visit and stay abreast of our XRF News.

Questions? Write to us now for a prompt expert response!

Industries we Influence
Metallurgy, Aero Space, Scrap and Recycling, Food Processing, Plumbing, Petrochemicals Metallurgy, Aero Space, Scrap and Recycling, Food Processing, Plumbing, Petrochemicals

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