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Nickel Barrier Thermistors

 

I am looking for information on how to achieve a nickel barrier terminaton on an NTC chip surface mount thermsitor. I am looking for materials as well as processing techniques. Any help would be appreciated.

Thank you! Doug Stolhand
- Westchester, California

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I have few questions for you,

1. What is the termination you are using now?
2. Does your product have a wrap around?
3. Is the component leaded?

If you have not formed the termination you can form using a silver epoxy paste which can be either dipped or coated using a roller to give a edge termination. This paste can be dried and cured to provide a good bonding.

This will be the base layer over which you can develop the Nickel barrier. The Nickel barrier can be developed by electroplating or electroless. Electroplating with small conducting media is proven to be a hassle free best option over electroless for such small components.

You can pre clean and Plate in Ni- sulphate bath (barrel plating) then go for Sn-Pb. You should atleast need 3 microns thickness of NIckel for the components to withstand the leach test and solderability test.

This is the technique used for plating the termination of SMD resistors and Capacitors. May ne for thermistors the same method should hold good.

Good luck .....

Karthik
- Singapore