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ZnAl

Special applications

ZINALIUM Coating

The ZINALIUM coating is made up of two layers: a layer of ZnAl  two-phase 85-15 alloy deposited by metallization with a minimum quantity of 400 g/m2 and a varnishing layer.

Product Range

PAM China supplies ductile iron pipes with ZINALIUM coating from DN100 up to DN2000.

Field of use

Usually ductile iron pipe with 130 g/m2 or 200 g/m2 zinc coating, can effectively protect the ductile iron pipe against the general type of soil corrosion. However, under strong corrosive conditions, ductile iron pipe lifespan is shortened. Through the use of Zinalium coating, pipe life can be increased by 3-4 times. The ZINALIUM-based coating is compatible with more than 90 % ground types, which includes:
- Wet areas such as ponds, swamps, mud and low-lying areas
- Saline Land
- Clay with poor permeability
- Area with stray current, such as near rails, high voltage lines etc.
- Metal mining area with low resistivity
- Chemical plants, waste disposal, thermal power plants, dairy plants and other industrial parks and agricultural parks
The pipe and active coating layer must be isolated from the soil in case of exceptionally corrosive environment.

Protective mechanisms

The metallic ZINALIUM coating offers active protection due to the galvanic action of the alloy. The mechanism has two effects:
1) Zinc-aluminum alloy forms during the spray cooling process with zinc phase and aluminum-phase interlocking homogeneously. Zinc phase oxides prior to cast iron, providing the cathode protection. And the oxidized dense compound prevents corrosion from the media intrusion. Aluminum phase is oxidized to form a dense oxide layer, which can greatly reduce the conversion rate of zinc, significantly increased anti-corrosion lifetime.
2) Restoration of continuity of the protective layer at points that have suffered limited damage (impacts during transport, scraping during backfilling).

Anti-corrosion performance in 500 Ω.cm soil for 13 years(Laid in 1985 and removed in 1998)

Advantages of the 400 g/m2 ZINALIUM coating

1. After 16 years of research, Saint-Gobain PAM optimize the composition ratio of Zn:Al to be 85:15 in the ZINALIUM coating, which renders the best anti-corrosion protection.
2. ZINALIUM coating can be applied to more than 90% of the soil corrosion conditions, which is much wider than the typical 130/200 g/m2 Zn coating. When soil corrosion is strong, the advantage of using ZINALIUM coating is more obvious.
3. Under the same corrosive conditions, the lifespan of pipes with ZINALIUM coating is 3-4 times longer than those with 200 g/m2 zinc coating;

4.Saint-Gobain uses advanced spraying process to ensure that the spray density reaches 400 g/m2, The use of zinc-aluminum alloy wire as a raw material ensures that the coating of zinc and aluminum components fully integrated to form a true alloy. Only in the true alloy state will the aluminum be able to effectively slow down the conversion rate of zinc and improve the pipeline lifespan.

Standards

Water supply: GB/T 13295,ISO 2531, EN545
Sewage: GB/T 26081,ISO 7186

Services

PAM technical teams carry out soil surveys at customers' request in order to recommend the most suitable protection.