BPS GOES INTO PRODUCTION ON TIN-ZINC

After a year of research and development we have refined our Tin-Zinc plating process to the point that we have gone into full automatic production. During this time the big three auto manufacturers have deepened their commitment to this finish. Boeing Aircraft is also looking into their own specification for Tin-Zinc. The reasons for the move from Cadmium are many. Ever since the dreaded "carcinogenic" label was placed on the Cadmium metal there has been a scramble to find a finish that would provide at least similar performance characteristics of Cadmium plating.

Other finishes were developed such as Zinc-Nickel, Zinc-Iron and Zinc-Cobalt. Some of these finishes performed well unless the part underwent some type of bending when it is installed, like a rivet does. The plating deposit simply does not bend with the part and flakes off, thus exposing the base metal. One of our customers manufactures blind threaded inserts. Their parts not only bend but are subject to torqueing problems due to the air powered installation tool that installs the insert. Cadmium is known for it's great lubricating characteristics. Nickel, Iron and Cobalt are all very hard, abrasive metals. Tin-Zinc being 70% Tin provides the ductility and lubrications that these inserts demand. We have tested this new finish and it has performed impressively in salt spray tests. With .0005" thickness we have achieved over 1000 hours before any red rust has formed. As you may remember from our article on salt spray testing, red rust means the plating has been compromised to the point that the part itself is beginning to rust. This is the test method that is used to compare the relative corrosion protection that a finish provides. This test has been repeated several times with the same results. This is evidence that Tin-Zinc actually outperforms Cadmium in similar tests.

Tin-Zinc, after chromating, is yellow in appearance, similar to Yellow Zinc but much duller. It has excellent conductive and soldering characteristics. If you would like to see what this finish looks like we can provide you with some samples. If your customer is looking for a highly resistant coating and they have some reason they can't use Cadmium, we can help you. Remember that Cadmium is still a great finish and we are committed to providing Cadmium plating for the many applications requiring it. Adding Tin-Zinc to the finishes we offer is an example of how BPS has shown a strong commitment to remain on the leading edge of plating technology.

Please contact us if you have any further questions.