Zinc alloys, what are they?
Zinc is a silvery or greyish metal, widely used in numerous industrial applications due to its multiple properties, especially as part of metal alloys.
Therefore, in this blog article, we are going to talk about what zinc is and its main alloys, uses and recycling.
What is zinc
Zinc (Zn) is a metallic chemical element with atomic number 30, forming part of the transition metals.
It is a malleable, ductile and moderately hard metal, so it can be easily stretched and rolled. It is also a very good conductor of heat and electricity and is not ferromagnetic.
Today, zinc is mainly used in the galvanising of steel to protect it from corrosion. But it is also used in batteries and computers, or in the production of injection moulded parts for the automotive industry.
It is also used for energy storage, e.g. in electrolytic batteries, as zinc uses a water-based chemistry, which results in the inability to spread fire and is therefore much safer.
Also in battery electrodes or zinc-ion batteries, which are safer, cheaper and more durable than lithium batteries. In addition, the raw materials used in zinc-ion batteries are more abundant than those used in lithium-ion batteries.
Zinc alloys
The best known zinc alloys are zamak, calamine and marine zinc.
Zamak
Zamak or zamac is a zinc-based alloy with aluminium, magnesium and copper. The acronym Zamak comes from these metals in German (Zink, Aluminium, Magnesium and Kupfer).
This alloy has a density of 6.6 g/cm3 and melting temperature of 368ºC. It has high hardness and high tensile strength, as well as good mechanical strength, plastic deformability and good castability. The latter refers to the ability of a molten metal to produce complete and flawless parts.
Advantages of using zamak
Since its creation, it is a material widely used in industry as it provides many benefits:
- Affordable price. It is a much cheaper metal than, for example, brass or steel, offering the same or even better results.
- Strength. Zamak is a hard, rigid and very resistant metal, so it is easier to deform it.
- High castability. As mentioned above, this is the metal’s ability to fit into all the holes in the mould to create complex and highly detailed parts.
- 100% nickel-free. The fact that it is nickel-free allows for high quality finishes, as well as the possibility of chrome plating, zinc plating or machining.
Calamine
Calamine is an alloy based on zinc, lead and tin in different proportions. This will depend on the needs and the search for a higher or lower quality of the final metal.
It is a metallic material, not very noble, cheap and brittle depending on the applications. Originally, it was used in times of scarcity of materials, due to its price. It is brittle, porous, soft and its colour changes and darkens, and over time it even degrades and sometimes even decomposes.
As scrap, calamine is therefore less common than other materials such as stainless steel or aluminium. However, it has value in the recycling industry because of its zinc content.
Marine zinc
Naval zinc is the name given to zinc anodes that are used as protection for the metal parts of a ship (shafts, propellers, rudders, etc.). These so-called sacrificial anodes are mainly used to protect the metal parts of ships.
The basic principle of this cathodic protection lies in the difference in electrical potential between metals. By connecting the anodes to the hull of the boat, an electrical circuit is established, and a current flow is created.
Once the boat is immersed in water, the anode becomes the electrical sacrifice. Due to their increased activity, the anodes corrode first, releasing electrons into the water. This electric current flows into the hull of the boat, which prevents it from corroding. Thus, the anodes are ‘sacrificed’, protecting the boat from corrosion.
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