Surface treatments of metals

There are different types of surface treatments that can be applied to protect metals from weather influences and damage. Each treatment has specific purposes and benefits. Common types of surface treatments for metals are:

• Paint coating: Applying paint to metal surfaces for decorative purposes and to protect against corrosion and weathering. This can be done with different paints, such as epoxy, polyurethane, and powder coating. In shipbuilding, welding primer Sigmaweld 199 is often used.
• Galvanisation or zinc plating: Galvanisation and zinc plating both refer to the application of a layer of zinc to metal surfaces to protect them from corrosion. This can be done via electrogalvanisation (dipping into a zinc bath using electric current) or hot-dip galvanisation (dipping into molten zinc).
• Anodising: An electrochemical process in which an oxide layer is formed on the surface of metals such as aluminium and titanium. This improves the corrosion resistance, wear resistance and aesthetic appeal of the metal.
• Chrome plating: Chrome plating is the application of a thin layer of chrome to metal surfaces to protect them from corrosion and rust, and to give them a glossy finish.
• Passivation: Applying a protective layer to metals such as stainless steel to slow the formation of rust and corrosion.
• Cementing: A heat treatment process that uses carbon-rich gas to harden the surface layer of steel, making it resistant to wear and corrosion.
• Basting: The use of abrasive materials such as sand, grit or steel grit to clean, degrease, roughen or polish the surface of metals.

The choice of a specific surface treatment depends on factors such as the type of metal, the intended application, environmental conditions and the desired properties of the treated surface.
 

Galvanisation

What is galvanisation?

Galvanisation is a surface treatment process in which a layer of zinc is applied to the surface of a metal object to protect it from corrosion. This process is often applied to iron or steel, but can also be used on other metals such as aluminium or copper. Galvanisation is widely used in various industries, including construction, automotive, electronics and the maritime sector.

The galvanisation process

This is what the galvanisation process looks like:

1. Substrate preparation: Before the galvanisation process begins, the surface of the metal object is thoroughly cleaned to remove dirt, grease, rust and other contaminants. This is often done by sanding, blasting, degreasing and/or washing.
2. Pickling: After cleaning, the metal object can be immersed in an acid bath to remove any oxidation or contaminants on the surface. This process is known as pickling and provides a clean and reactive surface for the galvanisation layer.
3. Galvanisation: Next, the metal object is immersed in a bath of molten zinc or electrolytically coated with zinc. During the galvanisation process, the zinc adheres chemically or electrolytically to the surface of the metal object, creating a protective zinc layer.
4. Finishing: After galvanisation, the galvanised object can be finished with a transparent sealer or other protective coating to further enhance its durability and aesthetics.

Benefits of galvanisation

Galvanising products has the following benefits:

• Corrosion protection: The main benefit of galvanisation is the excellent corrosion protection it provides. The zinc layer forms a barrier between the metal object and its surroundings, protecting it from rust, corrosion and other forms of damage.
• Long-lasting protection: Galvanised coatings have a long lifespan and require little or no maintenance for many years, making them cost-effective in the long run.
• Self-healing: If the galvanised coating is damaged or scratched, the zinc on the exposed surface can react with oxygen and water to form a protective layer of zinc oxide, preventing further corrosion.
• Environmental friendliness: Galvanisation is an environmentally friendly process because it does not use harmful chemicals or solvents and because zinc is a naturally occurring and fully recyclable material.
• Aesthetics: Galvanised coatings have a characteristic shiny finish that is aesthetically pleasing and fits well with various applications.

Galvanisation offers excellent corrosion protection and a long-term, cost-effective solution for protecting metal objects in various industries and applications.

The difference between galvanisation and zinc plating

Galvanisation and zinc plating are both processes used to apply a protective layer of zinc to the surface of another metal, usually steel or iron, to protect it from corrosion. Although the terms are sometimes used interchangeably, there are some subtle differences between the two processes:

• Galvanisation: A broader process in which a protective layer of zinc or other metals is applied to the surface of an object via electrolysis or thermal methods. It may involve zinc or other metals.
• Zinc plating: A specific form of galvanisation in which a layer of zinc is applied to the surface of a metal object, usually via electrolysis or immersion in molten zinc. It aims to protect metal objects from corrosion.

In essence, “zinc plating” refers specifically to the application of a zinc layer, while “galvanisation” is a broader term that can include other metals. In addition, a zinc layer applied during galvanisation is thin (5-40 µm). In zinc plating, the zinc layer is thicker (50-200 µm).
 

Powder coating

What is powder coating?

Powder coating is a surface treatment process in which a powder-like paint is applied to an object. This process is often used to provide metal parts with a durable, decorative and protective finish.

The powder coating process

This is what the powder-coating process looks like:

1. Substrate preparation: Before the powder-coating process begins, the surface of the object that needs to be coated must be thoroughly cleaned to remove dirt, grease, rust and other contaminants. This is often done through chemical treatments, sanding, blasting or washing.
2. Application of the powder: After the surface has been prepared, the powder coating material is applied to the object using a spray gun or electrostatic gun. The powder consists of finely ground particles of pigment, resins and additives that are electrostatically charged, causing them to adhere evenly to the charged surface of the object.
3. Hardening: After applying the powder, the object is placed in a furnace where it is heated to a certain temperature. During the curing process, the powder particles melt and form a uniform, durable coating on the surface of the object. This process is known as cross-linking and creates a strong chemical bond between the powder particles and the substrate.
4. Finishing: After curing and cooling the coated object, an additional finishing coat can be applied if required, such as a transparent top coat for extra gloss or protection.

Benefits of powder coating

Powder coating offers several advantages over other techniques:

• Sustainability: Powder coatings offer a durable and hard-wearing finish that resists scratching, corrosion, chemicals, UV radiation and weather influences.
• Environmental friendliness: Powder coating is an environmentally friendly process as it does not emit volatile organic compounds (VOCs) like traditional wet paint processes. Moreover, the excess powder can be recovered and reused, reducing waste.
• Uniform cover: The electrostatic process distributes the powder evenly and adheres efficiently to the surface, resulting in a uniform and consistent coating without drips or runs.
• Broad colour and finishing options: Powder coating is available in a wide range of colours, textures and finishes, making it possible to meet different aesthetic and functional requirements.
• Cost-saving: Because powder coatings have a longer life and require less maintenance than traditional paint coatings, they can be cost-saving in the long run.

Powder coating offers an attractive combination of durability, environmental friendliness, aesthetics and cost savings, making it a popular choice for protecting and beautifying metal objects in various industries and applications.
 

Sigmaweld 199

What is Sigmaweld?

Sigmaweld 199 is a 2-component welding primer with low zinc content. This welding primer is specifically designed to improve the weldability of metal surfaces and increase the quality of welded joints. Sigmaweld is available in several colours. Red-brown and grey are the most common colours.

Benefits of using Sigmaweld

Below are some important aspects of this product:

• Corrosion protection: Sigmaweld 199 forms a protective layer on metal surfaces, protecting them from oxidation and corrosion during and after the welding process. This helps extend the lifespan and durability of welded structures.
• Prevents welding spatter: Applying Sigmaweld 199 reduces the formation of welding spatter, resulting in a cleaner welding environment. This minimises the need for post-processing and improves the overall efficiency of the welding process.
• Compatibility: Sigmaweld 199 is typically used on steel. It can be applied via spraying, rolling or dipping, depending on the specific application and requirements.
• Applications: This product is widely used in industries where welding is an important component, such as shipbuilding, bridge and building construction, automotive, aviation, and petrochemical.

Overall, using Sigmaweld 199 as a welding primer contributes to improved weldability, increased productivity and better quality of welded structures, making it a valuable addition to the welding process.
 

Chrome plating

What is chrome plating?

Chrome plating is a surface treatment process in which a thin layer of chrome is applied to the surface of a metal object. This process is often used to protect metal parts from corrosion, wear and tear, and for aesthetic reasons.

The chrome-plating process typically involves the following steps:

1. Preparation of the surface: The surface of the metal object is thoroughly cleaned to remove dirt, grease and other contaminants. This ensures optimal adhesion of the chrome to the surface.
2. Degreasing: The part is degreased using chemicals to remove any remaining oil or grease residue that may hinder the adhesion of the chrome.
3. Sanding or polishing: If necessary, the surface of the part is sanded or polished to remove any irregularities, scratches or oxidation layers, creating a smooth surface for the chrome coating.
4. Activating: The part is treated with an acid to activate the surface and improve the adhesion of the chrome.
5. Electrolytic chrome plating: The part is immersed in an electrolytic solution of chromium salts, with the part acting as the cathode as a current is passed through the solution. During this process, chromium ions are deposited on the surface of the part, forming a thin, uniform layer of chromium.
6. Finishing: After chrome plating, the part can be polished to achieve a shiny finish. Sometimes, the part is treated with a protective lacquer as well to protect the chrome layer from scratches and oxidation.

The chrome-plating process is widely used in various industries, including automotive, home appliances, sanitation and more, because of the aesthetic and protective benefits it provides to metal surfaces.

Rob Snel’s product range includes some products in the locks product group which have been chrome-plated. These products are made of BMC (Brass Matt Chrome), which is brass coated with a thin layer of chrome.
 

Zinc plating

What is zinc plating?

Zinc plating is a process in which a layer of zinc is applied to the surface of another metal, usually steel or iron, to protect it from corrosion. Zinc plating of metal is often used in various industries, such as construction, automotive, shipbuilding and electrical.

The zinc-plating process

The process of zinc-plating has the following steps:

1. Substrate preparation: Before the zinc-plating process begins, the surface of the metal object is thoroughly cleaned to remove dirt, grease, rust and other contaminants. This is often done by sanding, blasting, degreasing and/or washing.
2. Pickling: After cleaning, the metal object can be immersed in an acid bath to remove any oxidation or contaminants on the surface. This process is known as pickling and provides a clean and reactive surface for the layer of zinc plating.
3. Zinc plating: Next, the metal object is immersed in a bath of molten zinc or electrolytically coated with zinc. During the zinc-plating process, the zinc adheres chemically or electrolytically to the surface of the metal object, creating a protective zinc layer.
4. Finishing: After zinc plating, the zinc-plated object can be finished with a transparent sealer or other protective coating to further enhance its durability and aesthetics.

Benefits of zinc plating

Zinc plating offers several benefits:

• Corrosion protection: The main benefit of zinc plating is the excellent corrosion protection it provides. The zinc layer forms a barrier between the metal object and its surroundings, protecting it from rust, corrosion and other forms of damage.
• Long-lasting protection: Zinc coatings have a long lifespan and require little or no maintenance for many years, making them cost-effective in the long run.
• Self-healing: If the zinc coating is damaged or scratched, the zinc on the exposed surface can react with oxygen and water to form a protective layer of zinc oxide, preventing further corrosion.
• Environmental friendliness: Zinc plating is an environmentally friendly process because it does not use harmful chemicals or solvents and because zinc is a naturally occurring and fully recyclable material.
• Aesthetics: Zinc coatings have a characteristic silver-grey finish that is aesthetically pleasing and fits well with various applications.

Zinc plating offers excellent corrosion protection and a long-term, cost-effective solution for protecting metal objects in various industries and applications.

The difference between galvanisation and zinc plating

Galvanisation and zinc plating are both processes used to apply a protective layer of zinc to the surface of another metal, usually steel or iron, to protect it from corrosion. More information