Element of the Month
Each month we will explore elements of interest from the periodic table, with a brief history of discovery and development, and a review of uses and applications.
Zinc - Atomic Number: 30 - Chemical Symbol: Zn
Zinc is a silvery-white metal with a bluish tinge. It was known in roman times when it was used to make brass casting alloys, but was first isolated as a metal in its own right in India from around 1100 onwards. In Europe zinc was first identified as a new metal in 1748 by German chemist Andreas Marggrat.
Zinc is a micronutrient, essential in human prenatal and postnatal development.
As a Pure Element
Zinc is predominantly used as a protective coating for iron and steel, deposited either by electroplating or galvanising processes. It is also die-cast to produce components for the automotive, electrical, and domestic hardware industries.
As an Alloy
There are many alloys that contain zinc, including brass (copper-zinc), nickel silver (copper-nickel-zinc), and zinc-aluminium solders.
Zinc based alloy coatings are increasingly used as sacrificial anti-corrosion coatings on steel, copper, and aluminium alloys. Their corrosion protection performance is many times better than zinc alone, and approaches that of cadmium without hazardous substance restrictions.
As a Compound
There are many Zinc compounds with a wide range of uses, including semiconductors, cosmetics, dietary supplements, and rodenticide.
Where Is Zinc Used?
Zinc coatings are widely used to protect functional substrates from corrosion in the automotive and construction industries. The degree of corrosion protection is directly related to the deposit thickness, so measurement and control of this parameter is critical to ensure correct performance in a specified lifespan.
Electroplated zinc alloy coatings such as zinc nickel are increasingly specified for automotive and aerospace components. Precise control of the alloy ratio is necessary to maintain optimum corrosion protection, and this is achieved using non-destructive X-ray fluorescence (XRF) for frequent analysis and control of the plating solution, and verification of thickness and composition of the coating.
Zinc die-casting is used to produce relatively low-cost components such as handles and trims for the automotive and domestic furniture industries, typically improved with electroplated copper and nickel, and electroplated chromium as the final bright finish.
Here are some key parameters for Zinc, quantifiable using instruments from Helmut Fischer GmbH
- Thickness of Zinc coatings on steel – in the range ~ 8 to 30 µm, measurable with a contacting probe instrument such as the Deltascope FMP30 or Phascope PMP10
- Thickness of Zinc coatings on non-ferrous alloys – in the range ~ 8 to 30 µm, measurable using an instrument such as the Fischerscope XDL 230
- Thickness + composition of alloy coatings such as Zinc Nickel – ~ 8 to 30 µm, measurable using an instrument such as the Fischerscope XAN 500
- Thickness of duplex coatings such as paint and zinc on steel, measurable simultaneously using an instrument such as the Fischerscope Phascope PMP10 Duplex. Learn more