The Medical, Automotive, Aerospace, Military and RF/Microwave Industries, regardless of their unique functions, often demand exceptional conductivity. Electro-Spec intends to meet the demands which sophisticated electrical components require.
Electroplating is a process whereby one metal is plated onto another via an electrodeposition method. Customers seek out electroplating for their parts for many reasons such as aesthetics, corrosion protection, increased hardness, wear resistance, increased conductivity, and decreased friction. It allows manufacturers to use base metals that are less expensive and apply a high quality coating to them to achieve the certain desired properties on the finished part.
Electro-Spec has been providing award winning electroplating and electroless plating services to customers for over five decades. This includes applications for lifesaving and safety critical components. Plating is available in precious and semi-precious materials including gold, silver, nickel, copper, Tri-M3TM (Tri-Alloy), electroless and electrolytic nickel. This short article discusses these plating options, as well as their benefits and examples of industries that they are often found of use within.
Products Finishing magazine names Electro-Spec to the ‘Top Shops” list
CINCINNATI, Ohio – Electro-Spec, Inc. has been named one of the best finishing shops in the U.S., according to an industry benchmarking survey conducted by Products Finishing magazine, a trade publication which has covered the industry since 1938.
Accounting for Plating Thickness in Assembly Design
The main consideration when plating threaded components would be to ensure that the plated threads properly fit into their mated counterparts. As shown in Figure 1-1, the dimensions to consider here would be the diameter and pitch of the threads. This translates into the tolerance of the plated coating being accounted for within the assembly because the plated coating will slightly change the geometry of the threaded component. The thickness of the plating should be accounted for when the part is designed. The most ideal location to account for the plated coating would be within the specifications of the mating part, including diameter and pitch. Of course, certain calculations are required to determine the slight change in the diameter or some other dimension of the mated part which will not impact the overall strength of the assembly. But, this is a calculation that should be performed before arbitrarily designating a plating thickness.
Given the importance of the plating process and the value of the material being used, it would be logical to assume that parts would be designed for the most efficient and effective electroplating possible. Unfortunately due to intricate engineering designs and micro miniature components, it is not always feasible to have a “plating friendly” part.
Electroplating, along with other finishing options, take their place at the end of the manufacturing process. It is incumbent on all parties, including the plater to work together in order to provide the best component possible.
Additionally, sometimes a part’s design will necessitate a difficult structure for applying even finishing, whether it’s electroplating or a more traditional finishing method. There are a myriad of reasons why parts are created with geometries that make them difficult to electroplate.
At its heart, passivation is a process that helps prevent corrosion and pitting on the surface of stainless steel. The passivation process applies a thin transparent passive chemically inert film to stainless steel that reduces the reactivity of the metal. This film deters corrosion, oxidation, and mild chemical attack.
While single-metal plating has been used for many years for a variety of industries, “White Bronze” or tri-metal (Tri-M3) plating is quickly becoming a suitable alternative. White Bronze plating offers superior corrosion resistance, low electrical resistance, non-magnetic properties, and extremely high hardness characteristics. It’s a less expensive approach to using silver and offers definitive health safety advantages compared to nickel. Due to its cost effectiveness and performance White Bronze is rapidly becoming the preferred plating for RF Connectors.
White Bronze centers around an alloy ratio of 55% copper, 30% tin, and 15% zinc. It offers the same bright white finish as plated alloys that contain nickel, silver, or rhodium. It produces smooth, low friction surfaces with non-porous characteristics and is also non-magnetic. White Bronze is ideal for soldering applications as it is lead-free, can be soldered with or without flux, and offers excellent leveling characteristics. The most important factor for tri-metal alloys in electroplating is the ability to control the % alloy mixture to achieve specific performance characteristics and properties. This has resulted in an increase use of White Bronze for the electronics and telecommunications industries and is a significant replacement to traditional tin and copper-tin alloy plating via silver or nickel.
Precious metal plating is an expensive process, especially because the standard method for improving corrosion is to increase the plating thickness. With self-assembled molecules (SAM’s), however, metal plating can be reduced significantly without losing corrosion protection. In addition to enhanced corrosion protection, SAM’s will also allow plated components to have increased conductivity.
Conductivity and Reduced Metal Thickness
Precious metal plated items, and in fact any plated item, experience increased resistivity because of uneven surfaces. This resistivity becomes even worse when the plating is thicker. Most manufacturers are forced to increase the thickness of the plating to stop corrosion, but this can decrease the performance of the item while increasing the cost of production. SAM’s addresses both of these issues. The molecular shield provided through SAM’s helps slow the corrosion process down and allows manufactures to use a thinner plating deposit.
When this happens, the conductivity of the plated item improves as well. This is because the plating is thinner and the molecular shield provides a more even surface that lowers resistance. Contact resistance due to uneven surfaces caused by thicker plating creates localized heating. With SAM’s, however, this problem is solved because the molecular shield fills the voids in any uneven surfaces of the plated component. The surface then becomes smoother, enhancing conductivity.
One of the major benefits of SAM’s is increased solderability, which is a result of increased corrosion protection the post-plate process gives the plated component. When precious metal experiences corrosion, it affects anything soldered to the metal. When the metal coating is protected by SAM’s, however, it resists corrosion for longer periods of time and improves solderability.
