Description

The pure zinc used in the past was subject to viscous creep and tended to tear under its own weight. The addition of titanium (min. 0.06%) and copper (min. 0.08%) solved this structural problem, creating a modern alloy perfect for the building envelope.

01The patina and white rust

Exposed to the atmosphere, zinc develops a compact layer of basic zinc carbonate (the protective patina), which ensures its extraordinary longevity. However, if water stagnates against the sheet in the absence of carbon dioxide, zinc hydroxide forms — a whitish, non-protective powder known as white rust — that perforates the metal. This is why zinc-titanium roofing always requires a ventilated cavity and a three-dimensional separation mat.

02Malleability and cold brittleness

The material lends itself to extreme forming and bending. A fundamental site constraint concerns cold brittleness: the alloy's crystalline structure does not allow bending if the material temperature is below 10°C. In winter, the coils must be pre-heated before working on site to avoid invisible micro-cracks.

03Industrial pre-patination

For immediate aesthetic requirements, manufacturers offer sheets given factory phosphate treatments that simulate natural ageing, available in Quartz (light grey), Anthra (slate) tones or pigmented finishes.

Technical identity

Standards

European and international references applicable.

EN 988EN 501QUALIZINC

Physical properties

Elastic modulus (E)~80-100 GPa
Thermal expansion (long.)22x10-6/gradi C
Thermal conductivity109 W/mK
Melting point418 gradi C

Usage environment

The underside of the sheets always requires ventilation and a three-dimensional separation mat to prevent white rust. The alloy is cold-brittle: below 10 degrees C it cannot be bent, so in winter coils must be pre-heated before site fabrication.

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