Qualified for Eureka Status.
TCB have built a new innovative diffusion coating plant incorporating the very latest technology for the coating of their bolts, nuts and washers. The process is a Thermo-Chemical Surface Modification (TCSM) and can be used for various metals, alloys, sintered ferrous-based materials, grey iron & cast iron.
TCSM production process (Greenkote®) is totally environment friendly. Unlike conventional coatings, Greenkote® does not produce any solid, liquid or gaseous toxic wastes. The process is also free of chrome, cadmium, acids, cyanides and chlorides.
Type of coating: PM-1.
Coating composition: Zn-Al polymetallic composition.
Main coatings' properties:
- Diffusion sacrificial corrosion resistance coating
- Thickness can be adjusted to suit different applications e.g. from 20 to 100µm
- Salt spray resistance - up to 1200 hours
- Long-term corrosion protection up to 350°C (752°F)
- No hydrogen embrittlement
- Thickness uniformity ±10% maximum
- Excellent preparation for painting, duplex coatings, adhesives and rubber mouldings. eg. from 20 to 100µm (TCB standard 25µm)
Comparison of Coatings in ASTM B117 Salt Spray Test
The criterion for failure was more than 5% of the sample area covered by red corrosion. The Greenkote® sample was acceptable after 800 hours of testing.