Choosing the Right Electroless Nickel Plating System: The pros and cons of multi-component and single-component electroless nickel 

Convenience, performance, and cost are important factors to consider when selecting the best electroless nickel (EN) chemistry for your plating shop.  With multiple manufacturers and a variety of formulations available, it is challenging to determine the best option. A good place to start is with a discussion of the the pros and cons of multi-component and single-component EN systems.

All conventional EN plating systems contain four essential ingredients: nickel (metal to be plated), sodium hypophosphite or hypo (reducing agent), chelation (maintains solubility), and stabilizers (prevents the tank from plating).  Unfortunately, these essential components are not always consumed at the same rate, which is important when considering the different EN systems on the market today.

EN plating baths have traditionally been made up using 3 components: “A” is the liquid nickel metal used for make-up and replenishment, “B” contains hypo, chelation and stabilizers, and is typically used only on make-up, and “C” is the replenishment component containing hypo and other important ingredients.  In an effort to improve convenience, manufacturers have modified this traditional formula and provided more options for customers.  There are now three main EN systems to choose from:

• 3 Component – Make up with A & B, and replenish with A & C
• Single Component Make-up – Pre-blended single make up component (MU) and replenish with A & C
• Single Component – One component used for both make-up and replenishment

Quality/Stability/Speed

The most important aspect of EN plating is ensuring the chemistry remains in balance and stable to maximize plating speed, deposit quality and productivity. The solution should be analyzed frequently to make sure both the nickel metal and hypo are at their optimum concentrations.  Other components such as chelation and stabilizers can be analyzed by the manufacturer and adjusted to account for high drag-out of these key components.  Any concentration imbalance presents a risk for poor quality, increased instability, slower plating speed and reduced productivity, so it is important to have full control over the chemical concentrations during the plating process. The 3-component system offers the tightest level of control and greatest flexibility because all the chemicals can be analyzed separately and adjusted accordingly. 

The single-component system offers the least amount of control over individual components.  In a single component system, if only the hypo is low, all of the additives (nickel, chelators, stabilizers) blended in the single component will also be added back to the bath, potentially causing an imbalance of other additives and unexpected negative consequences such as increased porosity, reduced phosphorous content and dullness in the deposit.  

Case Study – Deposit Properties & Plating Rate

A job shop in the Midwest operates a 215-gallon high phosphorous electroless nickel process tank.  The requirements for high phosphorous EN are typically determined by ASTM B733 Type V, which states that the deposit should have >10% w/w phosphorous content. Customer specifications also included requirements for salt spray, nitric acid resistance and plating speed. The company compared the 3-component and single component systems head-to-head to determine what was best for their application. 

The 3-component bath provided a consistent plating rate of 0.4-0.5 mil/hour through 4 Metal Turn Overs (MTOs), with 1 MTO equal to the amount of liquid nickel “A” used on make-up.  Also, the 3-component bath passed the nitric acid spot test, over 100 hours of neutral salt spray, and maintained greater than 10% phosphorous in the deposit. The average phosphorous content was 11.0%. 

The deposits from the single component bath failed to pass nitric acid spot tests and were prone to corrosion at 100 hours of neutral salt spray. The phosphorous content in the deposit ranged from 8.5-10.0 % w/w, below the ASTM specification. 

Additionally, the plating rate of the single component system dropped off significantly, as shown in the graph below.  The data proved that the 3-component system was the best choice for the job shop plater.

Cost

It is important to look beyond the price per gallon when determining the true cost of EN plating. The most accurate way to determine the plated EN deposit cost is to use a mil per sq.ft. calculator.  This calculator factors in the make-up and replenishment costs of all chemical components, the estimated EN plating bath life in MTOs, and the plating thickness of 1 mil, or one thousandths of an inch (0.001”) on one square foot of surface area.  For example, if 6 gallons of component “A” (nickel metal) is used on make-up, then every 6 gallons of “A” replenished back to the bath is equal to 1 MTO.  The longer a bath lasts, or the more MTOs you get out of a bath, the more cost effective it becomes.

Case Study – Cost-Benefit

A job shop plater on the West Coast operating a 1-component system performed a cost-benefit study on both the 1-component and 3-component systems. They first calculated the mil per square foot (mil/sq.ft.) cost for their 1-component system that typically achieved a bath life of 6-7 MTOs. They then installed a 3-component system and ran normal production through the bath to gather data.  

Operating out of the same tank with no change in process equipment, the 3-component system  achieved 10 MTOs. The mil/sq.ft. cost for the 3-component system was 34% less than the single component system. This number is significant, but the cost difference grows when you consider the single component system has a higher waste treatment cost (shorter bath life), more plate out (decreased efficiency), and a slower rate (reduced throughput). 

The company saved $21,000 a year by switching to a 3-component system.

Storage & shipping

Compared to the 2 & 3-component systems, which require multiple additives, the 1-component system has the convenience of one product for make-up and replenishment, and therefore it’s only one product to order. However, the 3-component system has highly concentrated additives. A standard 3-component system with a 6% A & 15% B make-up, and a 6% A & 6% C (1:1) replenishment requires approximately 170 total gallons to deposit 1,000 ounces of EN. The 1-component system needs 210 gallons or more to do the same work. This 20% reduction in chemical usage also provides savings in shipping costs over the life of a bath.

Ease of use

Whether using a one-component or multi-component solution, EN plating needs to be performed by properly trained personnel. Anyone who is not effectively educated is at risk of making costly, time-consuming mistakes. With labor shortages and the difficulty finding skilled workers, companies are looking to simplify operations any way possible. In this scenario it would seem logical to investigate a 1-component system that could help reduce chemical make-up time and minimize the number of products to order. The challenge is whether the reduction in labor provided by the single component system outweighs the performance and cost benefits of the 3-component system.

The bottom line

For some smaller EN applicators, the single component system may be attractive because it simplifies inventory and reduces order complexity. For new startups that plan to grow, purchasing a 3-component system in smaller package sizes such as 5-gallon pail quantities can keep up-front costs down while building the business. 

For mid & high volume EN applicators, the 3-component system provides the following benefits:

• Consistent plating speed and deposit quality
• Improved productivity
• Longer bath life
• Lower operating costs
• Lower waste treatment costs

Get Advice

Want help evaluating your EN plating options? Looking for a mil/sq.ft. plating cost calculator? JSA salespeople are technically trained to solve EN plating issues as well as other metal finishing related challenges.  Please contact your local JSA technical salesperson through the JSA office at 262-241-3200, or for more detailed information on electroless nickel and other related products please visit our website at or email us.