Electroless Nickel Plating
Electroless Nickel Plating - Aluminum Connecto
Electroless nickel plating is sometimes known as chemical or autocatalytic nickel plating. In contrast to the electroplating (galvanic) technique, chemical nickel plating baths work without an external current source. The plating operation is based upon the catalytic reduction of nickel ions on the surface being plated. To achieve good adhesion to the aluminum substrate, zinc immersion coating is used as a pre-treatment.
Electroless nickel has the following advantages:
- The need for complicated jig and anode arrangements is avoided
- A unique throwing power of the solution
- The coating grows at uniform speed all over the component. In many cases subsequent machining will not be required.
We specialize in a specific type of electroless nickel coating: Nickel-phosphorus plating
Due to its exceptional corrosion resistance and high hardness, the process has excellent application on items such as valves, pump parts etc., to enhance the life of components exposed to severe conditions of service, particularly in the oil field and marine sector.
Nickel-phosphorus plating is generally used for engineering applications. Our tried and tested method ensures the electroless nickel is deposited by the catalytic reduction of nickel ions with sodium hypophosphite in acid baths at a set temperature The deposits contains typically 3 to 13% phosphorus by weight.
The alloy obtained is dependent upon the chemical composition of the solution and the operating conditions. The phosphorus content significantly influences its chemical and physical properties in both the as-plated condition and after heat treatment.
We use three main types of phosphorus plating variants:
- Phosphorus content between 3 and 7%. These coatings have excellent high wear resistance and corrosion resistance.
- Phosphorus content between 9 and 12%. Corrosion protection and abrasion resistance are good enough for most applications. The plating bath works particularly economically.
- Phosphorus content between 10 and 13%. The coatings are very ductile and corrosion resistant. They fulfill the highest demands for corrosion resistance against chlorides and simultaneous mechanical stress.
Alternatives to Nickel Phosphorous Plating are:
Nickel-boron is very often used in industrial wear applications for its as-plated hardness, which is even higher than that of nickel-phosphorus. The boron content can be varied from 0.1 to 10%.
Poly alloys are a combination of nickel, boron or phosphorus and other metals such as cobalt, iron, tungsten, rhenium, or molybdenum.
CONTACT US to discuss which kind of plating is right for your application
Electroless Nickel Plating -
|We ensure that the Electroless Nickel deposits are very uniform in thickness all over the part's shape and size, even on complex shapes.|
Our plating process offers distinct advantages when plating irregularly shaped objects, holes, recesses, internal surfaces, valves or threaded parts.
- Electroless Nickel Plating Deposits are often less porous and thus provide better barrier corrosion protection to steel substrates
- Plating Deposits can be plated with zero or compressive stress.
- Resulting Metal finishes have inherent lubricity and non-galling characteristics
- Electroless nickel Deposits have good wetability for oils
- Low phosphorus and especially electroless nickel boron are considered solderable.
- Deposits are much harder with as-plated micro hardness of 450 - 600 VPN which can be increased to 1000-1100 VHN by a suitable heat-treatment
The versatility of electroless nickel plating is demonstrated by the wide range of coatings possible. The following are important types of electroless nickel coatings we have available
- Low Phosphorous (Hard)
The deposit is so uniform that grinding after plating is eliminated. Low Phosphorous Electroless Nickel offers excellent resistance to alkaline corrosive environments.
- Medium Phosphorous (Bright High Speed) Alternative to Stainless Steel
Steel parts plated with Medium Phosphorous electroless nickel will in many cases perform like stainless steel. Electroless nickel will not build up on edges or ends, and it plates inside and out giving uniform total coverage. With heat treatment, medium phosphorous electroless nickel can be hardened
- High Phosphorous
This finish provides maximum corrosion resistance. High Phosphorous electroless nickel is standard in industries that require resistance to strongly acidic corrosive environments like oil drilling and coal mining. High Phosphorous electroless nickel has a low degree of solderability. It will remain solderable for only a brief period of time after plating. This makes it a desirable finish for electronics parts such as connector housings and semiconductor packaging.
- Electroless Nickel/Teflon Composite
Teflon adds to the already slick surface of the electroless nickel, yielding a very low friction surface. This product is a relatively new one. It consists of microscopic beads of Teflon co-deposited up to 20% with the electroless nickel. This finish can be the solution to sticking, galling or drag problems with moving parts, or heated seal surfaces. In some cases, liquid lubricants can be eliminated with the use of Nickel/Teflon plating.
- Electroless Nickel on Zinc Die Cast
Electroless nickel can be applied directly to zinc die cast without a copper layer. This has many applications where corrosion resistance and resistance to chipping and flaking is necessary
|The selection of a specific grade of Electroless nickel plating is done in accordance with the nature of application, where a high hardness and low coefficient of friction is desired, low phosphorous electroless nickel is preferred (1-3%P). For general applications where a bright finish is required and the operating conditions are not very corrosive, medium phosphorous (6-8% P) electroless nickel is used.||
Electroless Nickel Plating - Steel Shell
When the conditions of use for an electroless nickel-plated components are severely corrosive, a high phosphorous electroless nickel (12-13% P) is usually selected. The high phosphorous electroless nickel is amorphous in nature and is compressively stressed unlike the low and medium phosphorous electroless nickel, which is Crystalline and tensile stressed.
- Surface Hardness: As plated 48-50 RC. After Heat Treatment (400°C, 1 hr) 62-63 RC
- Melting Point:- 890°C
- Density:- 7.85-7.95 gm/cm qb.
- Coefficient of friction:- Electroless Nickel Vs STEEL 0.3
- Coefficient of Thermal Expansion:- 0.13 microns /°c
Compared to nickel-plating, electroless nickel is about 50% more expensive. The reason is the frequent changes of the electroless nickel chemical bath
- The rougher the surface, the lower the corrosion protection.
- The more porous the substrate material, such as in castings, the lower the corrosion protection.
- The use of strong acids prior to electroless nickel-plating lowers corrosion protection.
- The use of sulfur-stabilized baths introduces deposit porosity that decreases protection.
- The higher the phosphorus content, the better the corrosion resistance.
- Corrosion protection decreases as bath age increases.
- Post-plate treatments such as low temperature baking, chromating, increase protection.
- Heat treatment for hardness decreases protection.