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Millivolt resistance on silver plated Aluminum for electrical components.

2000

We are plating silver (15 microns) on Silicon Aluminum alloys (German alloy, LM-25, HE-30 WP) on a fully automatic line having following pre-treatment:

1) Ultrasonic cleaning (Aqueous cleaner)

2) Hot Alkaline cleaning (without NaOH)

3) Acid Dip (75% HNO₃ + 25% HF - 3.5 mints)

4) Double Zincate

5) Silver Plating (40 gms Metal + 100 gms KCN)

The millivolt resistance between two silver plated components is fluctuating from 6 mv to 30 mv. I want to control the mv up to 5 mv. How shall I achieve this?

V.V.Sane
- Mumbai - India

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Apply some silver conductivity paste to the parts before assembly.

  
Tom Pullizzi
Falls Township, Pennsylvania
2000

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2000

Are you referring to CONTACT RESISTANCE? Bright plating systems incorporate carbon and sulfur into the deposits and cause contact resistance to increase. Some plating formulations are specifically made for low contact resistance.

Alternatively use a plain dull bath as per F.A. Lowenheim "Electroplating" ⇦[this on eBay , Amazon, AbeBooks affil links] or A.K.Graham [Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon affil links] ]. That should work. Y.V.Deval

Yashawant V. Deval
electroplating shop - Pune, Maharashtra, India