In nowadays, people focus more and more on life quality with the development of society. To protect&improve the environment and achieve sustainable development of the economy has been the primary consideration when most countries draft their development strategy for the new era.In July, 1999, Europe has passed a regulation about scrapped vehicle and vehicle parts. The “End of Life Vehicle Directive (EOLVD)” came into effect in 2006. Directive 4.2 and Directive 6.3 of it restrict the use of hazardous materials like Pb, Hg, Cadmium, Cr6+ etc, the specific limit is less than 2 grams per vehicle. With the issue of this directive, higher environment-friendly requirement has been raised for automotive parts. Therefore, Dacromet finish, the traditional surface finish for automotive industry were faced with big challenge.
Dacromet originate from the U.S in late 1960s, it was praised as breakthrough for surface treatment industry. Dacromet are largely applied in industries like Automotive, Construction, Railways, Electric, Bridges, Military etc then with its advantages like high rust-resistance, non hydrogen embrittlement, thin coating thickness etc. Dacromet finish is a totally closed process from pretreatment to coating layer forming, no water washing process and rarely hazardous waste water are produced. The main substance produced during baking is steam. It did reduce the heavy pollution caused by traditional surface finish like zinc plating or hot dip galvanization. But to be strict, Dacromet is not a 100% green technology, it can not be called green plating. It is because that there are about 2% Cr6+ in the treatment liquid per Dacromet process. Cr6+ is a well know hazardous substance which is toxic and carcinogenic. It has big threaten to our living environment, thus there are more and more strict restrictions to the use of Chrome. Although most Cr6+ has been turned into Cr3+ during Dacromet baking process, some Cr6+ still leave in the final coatings. Normally, its dissolution is less than 3ug/cm2, it still exceed 0.6 ug/cm2 limit which can cause allergy reaction. It may lead to serious consequences especially when the coating material has low quality or any mistakes in the handing process. To solve this problem, Dacral company in France adjusted the material for Dacromet coating fluid, they issued low Chrome content Dacromet named Dacromet LC in 1980s. The Cr6+ content has been put down to 0.03 ug/cm2 in the coating layer. Even so, it is still difficult to comply with more and more strict environment-friendly requirements. In this situation, the “no Chrome Dacromet” Geomet has been invented.

Geomet is a new surface finish technology developed by MCI company to meet the VOC arts and environment protection regulations for automotive industry. It is pushed to the market by NDS from Japan, Dacral from France and MCBI from Brasil together. This new non chrome coating had been widely recognized by automotive industry.
Geomet coating is silver gray in appearance, it looks darker than Dacromet. It is a inorganic coating which combine super thin zinc flake and Al flake together by special glues. Geomet protect materials from four aspects below 
1.Protective barrier: The zinc flake and Al flake layers provide a barrier between materials and air, thus obstructing rusting substance from contacting steel base.
2.Electrochemical function: Zinc flake sacrifice positive pole to be rusted to protect steel base.
3.Passivated function: The passivation slow down the rusting speed of zinc and steel base.
4.Self-healing function: When Geomet coatings are damaged, zinc oxide and carbonate will move to damage area and fix the coating to recover the protective barrier.
       

With this brief know-how to development of non chrome surface finish, it must be clear for you to learn why Geomet is getting more and more popular in daily production. To explore more about the finish, please feel free to call us or drop an email to sales@peakfasten.com. All your query shall be responded properly within 12 hours.