Harsh Environment Connector Plating: Meeting the Challenges of RoHS and REACH Compliance
Connector manufacturers and end-users are rapidly moving away from cadmium plating because it is no longer RoHS and REACH compliant. The health and environmental issues cadmium plating presents have led to revised standards and increasing demand for connector plating solutions that offer harsh environment performance comparable to cadmium but without its environmental side effects.
Connector manufacturers and end-users are rapidly moving away from cadmium plating because it is no longer RoHS and REACH compliant. The health and environmental issues cadmium plating presents have led to revised standards and increasing demand for connector plating alternatives. These new solutions must offer performance in harsh environments that is comparable to cadmium, but without its environmental side effects.
The Importance of Surface Plating
Aluminum is the market standard for metal connectors but cannot, by itself, provide the corrosion resistance and durability needed for use in harsh environments. Plating adds a coating to the aluminum connector to enhance properties such as conductivity, EMI shielding, wear, and corrosion resistance. This, in turn, makes a significant difference in a connector’s ability to perform in harsh environments. The choice of connector surface plating material has a major impact on this performance.
New Approach to Harsh Environment Connector Plating Is Necessary
Over the years, cadmium-based connector plating has been a popular choice in military, transportation, and aerospace applications for several reasons. These include its galvanic compatibility with aluminum, corrosion resistance even in environments where significant salt is present, EMI shielding, excellent conductivity, and its ability to be dyed in matte colors.
However, cadmium is problematic because it poses some undesirable environmental side effects and consequences related to long term use. This is especially serious in applications that require wash downs as part of their use and maintenance. For reasons such as this, the use of cadmium is being heavily regulated.
This demand for cadmium-free connector plating has come about as environmental legislation both at the national and international level has begun to require non-toxic connector plating alternatives. Because of this, new RoHS- and REACH-compliant plating materials are needed that can handle the harsh environments in which other materials, such as cadmium, excelled.
In addition, there are some end-users seeking to eliminate the use of cadmium and other toxic plating materials. For example, the German Army has mandated that any cadmium plated connectors must be replaced going forward and the replacements must be fully compliant with a new standard called J Plating.
Furthermore, there are also issues with another commonly used material associated with plating: Chromium VI (Hexavalent Chromium). In addition to platings that are cadmium-free, there is also a growing demand among end-users for plating solutions that are Chrome VI free in both product and process.
Keys to a Widely Useful Non-Toxic Plating Alternative
There are several important factors involved with finding a successful non-toxic plating alternative, such as safety, sustainability, RoHS/REACH compliance, and, most importantly, harsh environment performance. The search for such a plating alternative is simplified by the fact that RoHS and REACH compliant plating materials are typically proven to be safe for use and sustainable.
The major challenge for plating materials lies in the performance of a potential solution in a harsh environment, which can be quantified using tests such as static and/or dynamic salt spray resistance, salt fog testing, water immersion, and temperature cycling. Some operating environments may also require EMI shielding which is measured using attenuation tests. And for a cadmium plating alternative to be viable, it must also be highly conductive (which is often measured in terms of shell-to-shell conductivity). Furthermore, military applications often require that a connector plating solution is available in a very specific color and finish (e.g., olive drab or matte grey).
Non-Toxic, Harsh Environment Plating Solutions
There are several harsh environment plating solutions on the market that are compliant with both RoHS and REACH standards, as well as others. All of these options also offer excellent shell-to-shell conductivity and varying levels of shielding and corrosion resistance. Several of these plating solutions will be introduced below.
Tin Zinc J Plating
Tin Zinc J meets or exceeds the VG (German military) performance of cadmium and is fully approved and listed to VG95328, VG95234, and VG96929. It has been rated to 500 hours static / 5 days cyclic salt spray, making it extremely corrosion-resistant. It is also the official VG-approved 1-1 replacement for cadmium olive drab connectors. While originally developed for the military, Tin Zinc J can be used in all extreme environments where cadmium like performance is required. In fact, of the cadmium replacement options discussed, it is considered the best.
Epoxyurethanic Varnish Plating
Epoxyurethanic varnish plating works well for outdoor applications that require very high corrosion resistance. Often recommended for use in the railway industry, it offers good corrosion resistance (500 hours of static salt spray) but does not work well when signal integrity is a major concern.
Zinc Nickel Plating
Zinc Nickel (ZiNi) plating is considered a high-performance industrial alternative to cadmium-based plating. It provides excellent EMI shielding and is rated for 500 hours of static salt spray. ZiNi plating is suitable for a variety of applications including those found in industrial, construction, and transportation settings.
Zinc Cobalt Plating
Zinc Cobalt (ZiCo) plating works well as a solution for outdoor harsh environments and is used in industries such as industrial, construction, and transportation. It is EMI shielded for signal integrity and offers good corrosion resistance (rated for 200 hours of static salt spray).
As the regulation of cadmium grows and critical standards are forbidding its use as a connector plating, it is important to stay abreast of non-cadmium harsh environment plating alternatives such as Tin Zinc J, Epoxyurethanic Varnish, Zinc Cobalt, and Zinc Nickel.
ITT Cannon and Veam offer a leading and new plating system in the form of Tin Zinc J plating that provides 5 days/500 hours salt spray and shielding performance. Originally designed for use in ultra-harsh environments in the military, it is also ideal for other applications that need a non-cadmium, very high-performance plating solution. Tin Zinc J plating from ITT Cannon is a fully VG-approved cadmium replacement that is highly conductive (< 5 mOhm), corrosion-resistant, and available in non-reflective matte grey. Furthermore, it is chrome VI-free in product and process and is backward compatible to ITT cadmium and other platings.
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