Nickel – B

Special Electroless Nickel – Boron
For High Electrical Conductivity and Oxidation Resistance

Transene’s electroless nickel-boron process, NICKEL-B, offers unique characteristics (not equalled by nickel-phosphorous formulations) which are required by many electrical contact and bonding applications. NICKEL-B plates directly on oxide-free nickel / kovar / copper / tin. Plating on non-metallic surfaces may be accomplished by using Transene’s RTM Activator and Sensitizer.

Transene’s NICKEL-B metallization resists oxidation, has excellent electrical conductivity and may be plated, soldered, brazed or welded. The NICKEL-B plate has a boron content of 2-3%, electrical conductivity approximately equal to 60/40 tin-lead solder and plate hardness of 500 Vickers. NICKEL-B metallizations are more readily soldered than electrolytic nickel and electroless nickel-phosphorus, easily die-bonded using gold-silicon preforms and completely compatible with die attach epoxies.

Ultrasonic or thermal-compression wire bonding of aluminum to NICKEL-B bonding pads can be accomplished with results superior to those employing gold bonding pads. Electrical contacts plated with 0.20 mil NICKEL-B and 10 micro-inches of gold exhibit characteristics (conductivity / hermeticity) equivalent to 50 micro-inches of gold plated on electrolytic nickel.

PROPERTIES OF NICKEL-B

Appearance Blue solution, pH 8
pH control Ammonium Hydroxide pH range 7-10
Operating Temperature 60-70 °C
Plating Capacity (50% depletion) 1200 in2/0.5 mil/gal
Nickel metal content .65 oz/gal
Deposition rate 0.45 mil/hr
Composition of deposit 98% Ni, 2% Boron

PROPERTIES OF DEPOSITED NICKEL-B

M.P. 890 °C
Sp.Gr. 7.85
Coeff. of Expansion 130 x 10-6 in/in/°C
Hermeticity (0.15 mils) Leak rate: 10-8 cc helium/sec
Reflectivity 65%
Elect. resistivity (0.20 mil) 30 milliohm/sq.
Thermal conductivity 0.01 cal/cm2/cm/°C/sec
Hardness (as plated) 500 Vickers
Solderability (tin-lead) Excellent-flux not required
Brazing-silver (hydrogen/forming gas) Excellent @ 500-850

APPLICATION:

NICKEL-B operates @ 60-65 °C depositing autocatalytically on appropriate metallic surfaces. (RTM Activator and Sensitizer may be used on non-metallic surfaces.) Applications include: Burn-in contacts, connector pins and sockets, diode cans and transistor headers, heat sinks, lead frames, PC board fingers, capacitor bodies and ceramics.