Agrati Group - Hi-black Icon HIBLACK™

The high performing black ZnNi coating: ideal for wheel bolts and nuts.

Coating general description

HI-BLACK is a special ZnNi coating system.
It can be defined as a Duplex system due to its layer composition: alkaline ZnNi, high performing black passivation and high performing black topcoat. With its uniform matte black appearance, this coating has been specifically developed for applications with high demands in both mechanical and corrosion terms.

Technical advantages
  • Uniform matte black finish;
  • Very good adhesion and mechanical resistance, the coating appearance doesn’t degrade too much during the tightening operations;
  • High corrosion performance (NSST according to ISO9227):
    • White rust corrosion ≥ 480h
    • Red rust corrosion ≥ 1000h
  • High acid and alkaline resistances, corrosion performance is still high after acid and alkaline attacks;
  • Coefficient of friction: μtot = 0.09-0.15 (according to ISO16047);
  • High stability during multiple subsequent tightenings (20+ times);
  • High friction stability against the main automotive tightening surfaces:
    • Steel
    • Aluminium
    • KTL
  • Prevents stick-slip;
  • Good untightening performance at high temperature.
Application types
  • Wheel bolts
  • High corrosion performance black bolts and nuts
  • Bolts/nuts subjected to the action of acid/alkaline fluids
  • Bolts/nuts that need to be tightened multiple times with stable performance
Application process and environmental safety

Suitable for barrel application processes, it is Cr(VI) and heavy metal free.