GC TOP 471
Universal sealant for a refined look
The GC TOP sealing systems developed by Hillebrand Chemicals (Top Coats) offer a wide range of applications for visually attractive surfaces with simultaneously improved corrosion protection. They are designed to be used with GC PASS passivation. On electro depositions, the combination of these two coatings influences the chemical and mechanical resistance of the entire system.
GC TOP 471 is a universally applicable water-based sealant with pure organic components for centrifuge and barrel applications. In particular, black passivated zinc-nickel surfaces receive, with the help of the sealing coat, a homogeneous shiny, deep-black appearance with excellent salt spray resistance to greying. Zinc and zinc-iron surfaces also benefit significantly from the high-quality sealing product with regards to corrosion protection. The dry seal film is absolutely transparent and gives the galvanized part a particularly noble appearance.
The coating concentrate is used at 25 to 35 % strength and is ideally suited for processing in dry centrifuges with hot-air injection between 80 and 120 °C. Of particular note is the good-natured coating behaviour of the product thanks to its greatly reduced tendency to stick. This means a trouble-free process is possible. The dry film forms in the thin layer range of 0.8 to 2 µm. This is largely independent of the passivation structure and it has an excellent glossy appearance.
The typical greying which occurs for zinc-nickel from the effects of salt spray is delayed with just a very thin film of GC TOP 471. Properties such as ductility and impact resistance, give the sealing layer effective abrasion resistance and impact resistance and open up further possible uses for the product.
Corrosion resistance in accordance with DIN EN ISO 8227 depending on the substrate:
- Acid zinc 8–12 µm, DISP, GC TOP 471 WR > 168 h RR > 480 h
- Zinc-nickel 8–12 µm, black passivated, GC TOP 471 WR > 200 h RR > 1000 h
- Zinc-nickel 8–12 µm, transp. passivated, GC TOP 471 WR > 600 h RR > 1000 h