A process known as zinc plating is frequently used to protect metals such as iron and steel against the relentless forces of corrosion. Zinc plating involves the electrodeposition of a thin coating of zinc metal onto the surface of another metal object, known as a substrate. The zinc coating creates a physical barrier that prevents rust from reaching the underlying metal surface. Zinc is chosen because of its innate ability to fight corrosion. In fact, zinc is often referred to as the "corrosion-prevention workhorse".

The Step-by-Step Zinc Plating Process

Zinc plating is a relatively complex process that requires a high level of expertise. Specialized equipment and machinery is also required, including a rectifier, plating station, ancillary tank for proper dissolution of the zinc anode and a reservoir. Here’s an overview of how a typical zinc plating process works:

  Preparing and cleaning the surface — It’s essential to thoroughly clean the surface of the substrate prior to plating. Any debris or contaminants remaining on the surface will prevent proper adhesion of the zinc coating. An alkaline detergent solution is typically used for surface cleaning, which is followed by the application of an acid treatment to remove surface rust. This latter procedure is referred to as pickling.

  Preparing the plating solution — Zinc plating requires the immersion of the substrate into a specially formulated electrolyte solution, which is referred to as the plating bath. The bath consists of the zinc metal ionic solution and various chemicals that facilitate plating processes. They also help produce the desired chemical and physical properties of the finished product. Specific types of zinc electrolyte solutions include:

  Acid zinc — This is a widely used plating technology known for its high efficiency, fast deposition and superior covering power. However, acid zinc also provides poor throwing power and thickness distribution.

  Alkaline zinc — This offers less plating efficiency than acid zinc and a slower electrodeposition rate, but it provides better thickness distribution and ductility.

  Choosing the appropriate zinc plating procedure — After solution preparation, the parts are ready for plating. The chosen method could involve Rack Plating, where larger parts are affixed to metal racks which are placed inside the tank containing the plating bath. The parts remain stationary during plating. Barrel plating is normally used for smaller parts — instead of a plating tank, the parts are placed inside a barrel and rotated, which provides a more uniform finish.

  Introducing the electrical current — Electroplating is also known as electrodeposition because an electrical current is used to deposit metal ions onto the surface of the substrate. In the case of zinc plating, the substrate serves as the cathode. A DC current originating at the anode is introduced into the bath and flows to the substrate. The zinc ions are then deposited onto the surface. The current flows from the cathode back to the anode to complete the circuit.

  Post-treatment procedure — Upon completion of the electrodeposition process, the parts are ready for post-treatment. This normally involves rinsing the parts in water to remove any remaining contaminants and plating bath remnants. In cases of heavy contamination, the parts may need to be rinsed several times. The final step is to thoroughly dry the zinc-plated parts. In situations where additional corrosion protection is required, the application of passivates and sealers can be included in the post-treatment process.

Factors Impacting Zinc Plating Results

There are a variety of factors that can influence the outcome of a zinc plating project, most of which can be effectively managed and controlled by an experienced metal finishing solutions provider. Some factors include:

Current density — The density of the DC current flowing from the anode to the cathode can have a significant impact on the thickness of the zinc coating. The higher the current density, the greater the thickness coating. If the current density exceeds practical limits, a wrinkled substrate surface is likely to result.

Temperature — The temperature of the plating bath will also have a direct impact on the zinc plating outcome. Higher bath temperatures tend to reduce hydrogen diffusion on the cathode and increase the consumption of brighteners and other additives. There is also a close relationship between temperature and current density. When both are increased, the result will be a brighter zinc deposit. When the temperature increases but current density remains unchanged, the formation of larger metallic crystals will occur.

Zinc Plating Applications

Plating with zinc has many industrial applications. Zinc can provide a corrosion-resistant coating on smaller metal parts such as nuts, bolts, screws and fasteners. In general, most hardware parts are coated with zinc. Zinc plating has also gained widespread use in the automotive industry as a means of protecting parts such as brake pipes, brake calipers and power steering components.

Additionally, zinc plating is used in the production of tanks, armored personnel carriers and other heavy military vehicles. Zinc plating can also serve as a protective undercoating prior to painting, as it can promote greater paint adhesion.

Zinc Iron Plating
ZINC-IRON PLATING: PROCESS AND ADVANTAGES

Zinc is a shiny metal capable of being alloyed with various other metals. One of these is iron. Zinc-iron resembles zinc in color and other characteristics and both are popular plating metals. Yet, although we perform both types of plating at TECHNO SHINE , some clients actually prefer, zinc-iron plating. They select it more often than straight zinc plating because its properties are more advantageous in several ways including ease of further finishing.

What Is Zinc-Iron?

Zinc-iron is an alloy of two metals: zinc and iron. It is the result of zinc plating with the addition of an iron alloy. The content of iron resides between 0.3 and 1.0%. At TECHNO SHINE , our zinc-iron deposits typically contain 0.4 to 0.8% by weight.

The purpose of such product is to improve the existing properties of zinc. Zinc-iron plating works with the substrate metal component to further enhance and improve the properties of the base metal. This gives zinc-iron plated materials some advantages over a non-plated component.

Why Use Zinc-Iron Plating?

One important advantage of applying a zinc-iron layer to a substrate is improved corrosion resistance. Since zinc has a high resistance, by alloying zinc and iron to plate an item, you are increasing its resistance between 25 and 50%. At the same time, zinc-iron plating provides the substrate layer with other benefits, which include:

  Solid weldability

  Good ductility

  Excellent surface appearance

  Even distribution over even edged and irregular components

  Superior lubricity

  High level of hardness

  480+ hours of salt spray resistance

Zinc-iron plating is an excellent choice for components intended to undergo further manufacturing operations such as top coats and coatings, dyes, and waxes. This process also ensures the component will accept almost any color. In the automotive industry, for example, intense black chromate finish is very popular. Overall, perhaps the most attractive feature of zinc-iron plating is its ability to create a blacker part than can be achieved through the use of zinc plating technology.

Employing Zinc-Iron Plating

At Techno shine , we are industry leaders in zinc-iron plating. Companies who want improved and cost-effective corrosion protection for their products understand what the process can achieve for their components. We employ the latest in non-cyanide alkaline techniques to protect the environment while maintaining high quality standards and specifications.

 

THE IMPORTANCE OF PLATING

Plating is usually the only barrier between your parts and the atmospheric working conditions. Often, there is no plating applied to an end product, so very early in the life of the part, corrosion and wear deteriorates functionality and ultimately the total unit which it was assembled into. You don't have to settle with the alternative of using expensive metal alloys such as stainless steel in the future or a lesser quality electroplated finish to keep your parts from failure.

APPLYING ELECTROLESS NICKEL PLATING SOLUTIONS

One form of plating that is commonly used in many industrial applications is nickel electroplating, which offers excellent corrosion protection and increases wear resistance. However, electroless nickel plating solutions are often chosen as an alternative to nickel electroplating. Unlike nickel electroplating, electroless nickel plating does not require the use of an electric current to produce the desired reaction. Instead, the deposition of the nickel metal occurs via autocatalytic reaction.

The advantages of electroless nickel plating solutions include:

  No need for an electric current, which can minimize utility bills

  Easier to achieve an even coating on parts

  Greater flexibility in terms of coating volume and thickness

  Automatic monitoring of chemical replenishment during the plating process

  Ability to achieve various levels of finish brightness

By applying electroless nickel plating, you'll have peace of mind knowing that your parts will last indefinitely in accordance to a proper engineering specification. You won't have to worry any more about the rising cost of exotic metals and the burdening detriment of electroplating that creates out-of-tolerance parts and lack of mechanical and environmental protection. The risk of corrosion and wear will be abated.

ELECTROLESS NICKEL PLATING SOLUTIONS FROM TECHNO SHINE

Many original equipment manufacturers (OEMs) come to techno shine for their electroless nickel plating needs. OEMs want to make end products with an advantage over the competition. Other electroless nickel customers are job shops that want to improve their machined components value. Our industrial plating company has electroless nickel plating solutions for products of varying degrees of use ranging from simple corrosion protection to others in need of better wear resistance created by occluding and infusing materials like ceramics into the coating and also low friction composites such as fluorinated carbons to create a dry self lubricating coating.

Copper Plating
HISTORY AND ATTRIBUTES OF COPPER AND COPPER ELECTROPLATING APPLICATIONS

Copper is a reddish-orange natural metallic element that is mined from beneath the surface of the earth. In its purest form, it is relatively soft and malleable, making it an extremely useful and accessible material for both traditional tools and modern applications.

Copper was known to mankind’s earliest civilizations. For a thousands of years, it has been used in a variety of ways ranging from decorative jewelry and artistic sculptures to durable work tools and kitchen cutlery.

Most believe copper was among the first metals, along with gold and iron, to be used for practical and aesthetic purposes. Early metallurgical techniques developed over time include cold working, annealing (heat treatment), smelting (extractive metallurgy) and lost-wax casting.

Today, copper electroplating is a highly refined and effective method many industries rely on. Copper's excellent thermal and conductive properties make it a particularly useful substance in numerous heating, industrial and electrical applications. Copper is also commonly used in corrosion protection.

The many applications of copper plating include use as an undercoat in situations where enhanced adhesion for additional coatings of other materials is desirable, as it provides smooth and uniform coverage. Copper electroplating can be used as a treatment for the preparation of surfaces for soldering. It is also common for industries such as aerospace and electronics to apply copper plating on plastic applications.

COPPER ELECTROPLATING

Copper electroplating is sometimes used as a heat treat stop-off for masking, as it allows for selective heat-treating when needed. Additionally, electroplating copper may be used in a variety of plating applications where high electrical conductivity and greater thickness build are required. Copper electroplating is sometimes used in electroforming and for the metallization of non-metallic materials, as exemplified by copper plating on plastic. It is also used with semiconductors and for printed circuits through hole plating.

ADVANTAGES OF ELECTROPLATING COPPER

With regard to electroplating, copper offers many benefits. Copper is a soft and malleable metal, making it an excellent choice for electroplating with other flexible metal materials or objects. Copper won't separate from other metals even when it is bent. Copper's excellent conductive properties makes it more effective than other materials for use with electrical components, which is the reason copper electroplating is widely used in the electronics industry. When used as a base coat for nickel steel plating, electroplated copper provides superior protection against corrosion in comparison to other materials.

 

The GEOMET® product range is a standard worldwide reference for industries requiring high performance thin layer anticorrosion systems. GEOMET® products are completely chrome-free and capable of protecting a wide variety of metallic surfaces. The coatings are well suited for protecting both large and small parts, having either simple or complex geometry. In particular GEOMET® coatings are a worldwide standard for use on fasteners.

GEOMET® 720

GEOMET® 720 is applied to protect fasteners and many types of metallic parts from corrosion and is used in many industries. It can be combined with PLUS® topcoats to provide a very broad range of friction coefficients. It is the reference zinc flake coating in Asia.

  Thin dry-film, non-electrolytic

  Water-based chemistry

  Passivated zinc and aluminum flakes in a binder, patented chemistry

  Metallic silver appearance

Characteristics and performances

  The coefficient of friction can be adjusted to targeted values ranging from 0.06 to 0.20 (ISO 16047) with NOF METAL COATINGS GROUP's selected topcoats

Salt Spray Test (ISO 9227)
1000 hrs without red rust

  No hydrogen embrittlement

  Excellent assembly and multi-tightening behavior (with lubricated topcoat)

  Performance maintained at elevated temperatures (up to 300°C)

  Paintable coating

  Electrical conductivity for most application processes

  Bimetallic compatibility with aluminum

GEOMET® 321

GEOMET® 321 is applied to protect fasteners and many type of metallic parts from corrosion and is used in many industries. It can be combined with PLUS®, DACROLUB® or GEOKOTE® topcoats to provide a very broad range of friction coefficients. It is the most widely used product in zinc flake technology.

  Thin dry-film, non-electrolytic

Salt Spray Test (ISO 9227)
240 hours without white rust
720 hours without red rust

  Water-based chemistry

  Passivated zinc and aluminium flakes in a binder, patented chemistry

  Chrome free alternative to DACROMET® 320

  Metallic silver appearance

GEOMET® 360

GEOMET® 360 has been specially formulated to protect brake discs against corrosion. The brake disc surface can be totally treated with a coating at a thin layer, still providing high performances without any influence on braking characteristics. GEOMET® 360 is obtained from a water-based dispersion of zinc and aluminium flakes. The color of the coating is silver Characteristics and performance*

  Cosmetic protection: the brake discs can be seen through the alloy wheels. The aluminium silver color of GEOMET® 360 integrates perfectly with the style of alloy wheels

  Braking behavior: the low thickness of the coating on braking surfaces does not damage the quality of braking during the vehicle first use and enables a temporary protection of brake discs surfaces

  Temperature resistance (400°C): it enables to keep an excellent corrosion resistance on vehicles

  Protection inside the vents: no oxidation inside the fins – better thermal exchange while braking

  For after-market, GEOMET® enables to assemble the brake discs on vehicles without pre-degreasing (dry protection)

  The stronger corrosion protection of GEOMET® on the hub mounting surface makes brake disc dismounting easier

GEOMET® 500

GEOMET® 500 is applied to fasteners and many type of metallic parts to protect from corrosion, and it is used in many industries

  Thin dry-film, non-electrolytic, self-lubricated

  Water-based chemistry

  Chrome free alternative to DACROMET® 500

  Metallic silver appareance

Characteristics and performance

  Coefficient of friction: 0,15 ± 0,03 (ISO 16047)

Salt Spray Test (ISO 9227)
240 hours without white rust
720 hours without red rust

  No hydrogen embrittlement

  Excellent assembly and multi-tightening behavior

  Good mechanical damage (test method D24 1312, USCAR 32) and chemical (test VDA 621-412) resistance

  Performance maintained at elevated temperatures (up to 300°C)

  Paintable coating

  Electrical conductivity for most application

  Bimetallic compatibility with aluminum

 

PLUS SERIES

Top coats add new characteristic to GEOMET coatings and improve various coating performance

  Realization of consistent friction coefficient. Choose an applicable specification from a qide selection in order to achieve a stable friction coefficient for GEOMET coated.

  Improve corrosion resistance of GEOMET Applying GEOMET PLUS series over GEOMET coated will further improve the corrosion and chemical resistance .( Salt Spray Test according to ISO 9227 / ASTM B117 GEOMET®720 + TOP COAT > 1500 hours without red rust)

  For beauty of appearance (Black color coating) Meet customer's requirement of black color surface

  Improved resistance to galvanic corrosion The GEOMET PLUS series has been used by auto manufacturers as a means of preventing galvanic corrosion on the GEOMET coated metal fittings of robber hoses, such as hose clamps.

  The water-based, chromium free coating technology does not cause pollution.

DACROLUB® 10

DACROLUB® 10 is an organic topcoat made from water-based chemicals. This topcoat can be applied to GEOMET® and DACROMET® coatings, whereby the friction coefficient of threaded parts can be reduced and controlled.

Characteristics and performance

  Dry lubrication film

  Friction coefficient: 0,08 - 0,14 on parts with GEOMET® or DACROMET® measured according to EN ISO 16047

  DACROLUB® 10 gives freedom from possible stick-slip problems when tightening (VDA 235-203)

  No induced hydrogen embrittlement

  Appearance: clear • Salt Spray Test according to ISO 9227 : No effect on the corrosion resistance of the GEOMET® or DACROMET® base-coat

  The combination GEOMET® / DACROLUB® 10 or DACROMET® / DACROLUB® 10 is particularly suited to fasteners since it provides them with optimal protection and assembly properties

  Being easy to apply, the DACROLUB® 10 can be colored to be used for part identification

GEOKOTE®

  Resistance to chemicals and abrasion, improved control of the friction coefficients are requirements increasingly demanded by markets. The combination of the GEOMET® coating with the GEOKOTE® topcoats can respond to new expectations in many industrial sectors.

Characteristics and performance

  Strong resistance to hydrochloric, phosphoric, sulfuric acids, automobile fluids and other chemical agents

  Stronger resistance to repetitive abrasions

  No hydrogen embrittlement

  The black, clear or other shades of GEOKOTE® gives freedom from possible stick-slip problems when tightening (VDA 235-203)

  The GEOMET® / GEOKOTE® combination is particularly suited to fasteners since it provides them with optimal protection and assembly properties

  Salt Spray Test according to ISO 9227 GEOMET® 720 + GEOKOTE® > 150 hours without red rust