Colored zinc plating screw nut
Time: 2018-09-25 Reads: 1659 Edit: Admin
The difference between colored zinc plating and environmental protection colored zinc plating
Is environment-friendly color zinc plating better than color zinc plating?Where is good?why
The difference between chrome plating and environmentally friendly color zinc is that hexavalent chrome is used for galvanizing and trivalent chrome is used for chrome plating. The color of the zinc-plated color is the variegated color of the rainbow or the spotted. The color of the environmentally friendly color zinc is generally blue. The toxicity of valence chromium is a hundred times that of trivalent chromium.

Hexavalent chromium has a good effect and low cost, but it is toxic and not environmentally friendly. It is now passivated with trivalent chromium or chromium-free, but it is not resistant to corrosion. Zinc plating will use trivalent chromium passivation to improve the corrosion resistance of the coating, and trivalent chromium passivation can also produce decorative effects such as blue, multicolored and black.

After the passivation of the zinc plating layer, a passivation film or a white passivation film of different colors is usually obtained depending on the passivation liquid used. The rainbow-colored passivation film is five times more resistant than the colorless passivation film. This is because the iridescent passivation film is thicker than the white passivation film; on the other hand, when the surface of the iridescent passivation film is scratched in the humid air, the hexavalent chromium in the passivation film near the scratched portion is scratched. The part is re-passivated to repair the damage and restore the passivation film. Therefore, the galvanization is mostly iridescent. The colorless passivation film has a white appearance and is often used in daily hardware, construction hardware and the like which require a white uniform surface. In addition, there are black passivation and military green passivation, which are also used in industry.

Hexavalent chromium is a toxic poison/inhalation of extremely toxic substances. Skin contact may cause allergies; it is more likely to cause genetic defects, inhalation may cause cancer, and it is a persistent risk to the environment. But these are the characteristics of hexavalent chromium, and chromium metal, trivalent or tetravalent chromium do not have these toxicities.

Hexavalent chromium is easily absorbed by the body and can invade the body through digestion, respiratory tract, skin and mucous membranes. By breathing different concentrations of chromic anhydride in the air, there are varying degrees of hoarseness, atrophy of the nasal mucosa, and severe nasal perforation and bronchiectasis. It can cause vomiting and abdominal pain when invaded by the digestive tract. Dermatitis and eczema occur when invaded by the skin. The most harmful is the risk of cancer when exposed to long-term or short-term exposure or inhalation.

Hexavalent chromium compounds are carcinogenic in the body and cause a number of other health problems, such as inhalation of certain higher concentrations of hexavalent chromium compounds that can cause runny nose, sneezing, itching, nosebleeds, ulcers and perforation of the nasal septum. Short-term, high-dose exposure can have adverse consequences at the site of contact, including ulcers, nasal mucosal irritation, and nasal septal perforation. Ingestion of very large doses of chromium can cause kidney and liver damage, nausea, gastrointestinal irritation, stomach ulcers, cramps and even death. Skin contact can cause ulcers or allergic reactions (hexavalent chromium is one of the most susceptible to allergic metals, second only to nickel).

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