PPGI stands for Pre-Painted Galvanised Steel, while PPGL stands for Pre-Painted Aluminium Zinc Plated Steel. As the name implies, PPGI uses galvanised sheet (with a zinc coating) as the base metal. PPGL, on the other hand, is based on an aluminised zinc sheet coated with 55% aluminium, 43.3% zinc and 1.6% silicon. This is the main difference between PPGI and PPGL, which will further influence their function and application.

As mentioned earlier, both zinc and aluminium-zinc coatings are used to protect the metal from rusting to prolong its life. In the case of GI sheets, when the zinc coating is completely corroded, it will damage the base metal. Generally, galvanised sheets will last 10 to 15 years. Aluminium and zinc alloys, on the other hand, form areas of microscopic particles. The zinc-rich phase corrodes preferentially, while the aluminium-rich phase corrodes very slowly. This is why Al-Zn coatings are more resistant to corrosion than galvanised steel. According to information, the service life of PPGL is three times longer than that of PPGI.

Both PPGI and PPGL sheets are widely used for wall panels and roofing. In contrast, PPGL has better corrosion resistance, which means it is more suitable for harsh outdoor environments. In addition, it is widely used for chimney pipes, ovens and lampshades due to its good heat resistance and good surface conductivity. However, PPGL has less cutting edge protection. So you can use rust-proof paint or zinc-rich paint on the cutting edges.