With the exception of proprietary interfaces requiring special connectors, most connector types and configurations haven’t changed significantly since their creation. For example, we still use the standard two- and three-prong plugs we all grew up with for ac-power connections in the U.S. Similarly, audiophiles aren’t giving up their composite RCA connectors anytime soon.
Most standard computer/digital connectors such as DB-9, D-Subs, and DB-25 (Centronics/parallel-port) are still around. So is the waning FireWire interface. USB cables aren’t going anywhere. And with more consumers interfacing their home entertainment centers to the Internet, HDMI looks like a long-haul interface as well.
Again, except for certain proprietary and specialized interfaces (Fig. 1), no new jacks or plugs loom in the near future. Advances in interconnects appear to come by continually improving existing products, such as the progression from USB 1.0 to 3.0 and increased data rates over optical cable.
These enhancements often are offered as options. Sometimes these options include the coating or plating on the material connector contacts. Until now, and no pun intended, the “gold standard” for connector plating has been gold. But according to Swedish company Impact Coatings, that’s changing.
The company has developed a material that can replace gold as a plating material on electrical contacts. Called Silver MaxPhase, the metal-alloy material physically and electrically performs like gold, but at a much lower cost. With gold prices fluctuating lately, Silver MaxPhase is a timely and welcome innovation.
Going For The Gold Or Silver
Gold is more than an excellent conductor. It’s also durable and offers high resistance to corrosion. Tarnish and corrosion not only threaten a reliable physical connection, they also increase resistance and can degrade signal integrity, reduce signal level, or, in the case of power connections, generate unwanted heat.
Silver and copper are more conductive per volume than gold. In fact, annealed copper is the international standard that other electrical conductors are compared to. But copper and silver both tarnish easily, silver more so than copper. And while silver is more conductive than copper, it’s more costly and less practical, too. It’s used as a thin plating to minimize skin-effect losses.
Gold is vulnerable to corrosion from free chlorine, an unlikely condition in most connector applications, though it stands up well against non-chlorinated acids. Hence, gold is used widely in industrial markets and in the more expensive electronics cables, such as audio, video, and USB cables (Fig. 2).
Gold contacts also offer some value-added amusement, particularly in high-end audio components. Most audiophiles believe and swear that gold connectors sound much better than any other materials. Of course that’s purely subjective and hinges on knowing which end of the cable to stick in one’s ear. Essentially, gold-plated contacts are deemed almost essential in highly humid atmospheres and in high-reliability applications where failure is not an option.
The Affordable Alternative
“We want to challenge the idea that gold plating is the only option for electrical contacts,” says Henrik Ljungcrantz, CEO of Impact Coatings. According to the company, Silver MaxPhase is a gold replacement material that will cut the costs of electrical contacts. In terms of electrical conductivity and resistance to wear and corrosion, it performs like gold while carrying a much lower price tag.
Also, the material doesn’t require any hazardous chemicals in its processing, making it environmentally friendly. Silver MaxPhase coating is qualified to IEC 60512 and IEC 60068 standards for low-voltage and low-contact-force connectors that traditionally feature gold plating, including battery and I/O connectors for mobile phones and the plethora of other connectors on the market (Fig. 3).
In addition to developing Silver MaxPhase, Impact Coatings specializes in physical vapor deposition (PVD). This process, which the company says has no negative impact on the environment, employs a vacuum chamber in which Silver MaxPhase is evaporated and then condenses on the target object (connector).
Impact Coatings offers a range of PVD machinery with a significantly smaller footprint than a traditional wet plating equipment (Fig. 4). These units easily integrate into existing production flows. Again, with considerably less environmental impact compared to gold-plating processes, Silver MaxPhase production lines will not conflict with environmental legislations or require special permits. PVD machines available include systems for high-capacity coating of metal strips packaged on reels, systems for coating individual metal parts, and systems for coating plastic components.
Impact Coatings is pretty tight-lipped about any in-depth specs for Silver MaxPhase, and you really can’t blame the company because there is a large market for gold-plated components. If all it claims is true, Impact Coatings appears to be set to take a big chunk of it, particularly the cost-conscious and environmentally responsible segments.