Fischer measurement technology
Published

Low-Stress Nickel Deposit

What is a low-stress nickel deposit?

Share

Q. We just received a large order for plating parts with “low stress nickel.” What is a low-stress deposit? P.N.

A. As you are probably aware, there are different types of nickel plating baths. The workhorse is the Watts nickel plating bath, which consists of nickel sulfate, sulfuric acid, small amounts of chloride ion and water. This particular bath gives a deposit with residual stress, and that residual stress can cause peeling, blistering and tearing of the deposit. In addition, the deposit may be warped or cracked, and adhesion can be reduced dramatically.

The residual stress in the nickel deposit is affected by the plating bath composition. This table shows some stress values for different types of nickel plating baths:

 

Solution Anion

Residual Stress (psi)

Sulfamate

8,600

Bromide

11,300

Fluoborate

17,000

Sulfate (Watts Bath)

23,100

Chloride

33,000

 

There are two ways that residual stress can be reduced in a plating situation. Stress reducing agents such as saccharin can be added to the bath, or, if the customer specifies a low-stress deposit that is additive-free, a sulfamate-based plating solution is called for. The sulfamate plating bath is more expensive than the Watts-type bath.

The substrate itself also can influence the residual stress of the deposit, as can the temperature of the bath. For example, the stress from a nickel sulfamate plating bath at a temperature of 65°F is 13,200 psi, but 2,500 psi at 104°F.

A good book that discusses the causes of residual stress in more detail is Electrodeposition – The Materials Science of Coatings and Substrates by Jack Dini, which is available on Amazon.com. 

Related Content

  • How to Choose Between Sulfate and Chloride-Based Trivalent Chromium

    There are several factors to consider when choosing between sulfate and chloride-based baths for trivalent chromium plating. Mark Schario of Columbia Chemical discusses the differences and what platers should keep in mind when evaluating options.

  • Troubleshooting Alkaline Zinc

    One of the most common problems that can arise when plating with alkaline zinc is an imbalance of brightener in the solution. In this helpful Ask the Expert article, Chad Murphy of Columbia Chemical discusses how different zinc metal concentrations and brightener concentrations can impact efficiency.

  • Zinc Electroplating

    Choosing the best process for your operation.

Hitachi High-Tech FT200 series
In-Place Repairs for Canning Presses
Reduced Ion Electroless Nickel
Luster-On Products
Rectifiers for the Plating Industry
KCH Engineered Systems
FISCHERSCOPE® XAN® LIQUID ANALYZER
Pretreatment Washer and Finishing Equipment
Rectifiers for the Plating Industry