Main Difference between PPGI and PPGL

PPGI and PPGL sheets are two different color-coated steel sheets, which are widely used in various industries, such as advertising, construction, transportation, home appliance industries, etc. They are very similar, but there are still some differences.

PPGI uses galvanized sheet (with a zinc coating) as the base metal. The PPGL is based on aluminized zinc plate, coated with 55% aluminum, 43.3% zinc and 1.6% silicon. This is the main difference between PPGI and PPGL, which further affects their function and application.
For GI sheet, the base metal can be damaged when the zinc coating is fully corroded. Generally speaking, galvanized sheet can be used for 10 to 15 years. Whereas aluminum and zinc alloys form microscopic grain regions. The zinc-rich phase corrodes preferentially, while the aluminum-rich phase corrodes very slowly. So Al-Zn coating is more corrosion resistant than galvanized steel. According to the data, the service life of PPGL is 3 times that of PPGI.
At the same coating thickness, the Al-Zn coating is lighter than the zinc coating. This is because the specific gravity of aluminum is lower than that of zinc.
The surface of PPGL sheet is smoother than that of PPGI sheet. This is because aluminum adheres better than zinc. For the same reason, PPGL sheets can be painted directly without pretreatment.
The heat resistance of PPGL sheet is better than that of PPGI sheet. PPGL sheet can withstand the temperature of 315 ℃. In addition, PPGL sheet has better corrosion resistance than PPGI.
Both PPGI and PPGL sheets are widely used for siding and roofing. In contrast, PPGL has better corrosion resistance, which means it is more suitable for harsh outdoor environments. In addition, due to its good heat resistance and good surface conductivity, PPGL is widely used in chimney pipes, ovens and lampshades, etc.