What is blue chromate?

What is blue chromate?

BLUE CHROMATE. Our blue chromate concentrate produces a true blue conversion coating on zinc plated items. It is a single dip blue trivalent chromate that offers high salt spray resistance for up to 130 hours to white rust corrosion, and 160-200 hours to red rust corrosion.

What is blue dyed zinc plating?

Blue Zinc also known as clear passivate or silver zinc. Traditionally the blue chromates provided up to 48 hours protection to white corrosion in a salt spray cabinet. However we now also offer Hexavalent Free, Trivalent Blues these provide in excess of 120hrs to white corrosion.

Is chromate conversion coating hazardous?

The major concern nowadays with chromate conversion coating is its toxicity. Hexavalent chrome is toxic and causes cancer in people. Hexavalent chrome is toxic to aquatic life and virtually all mammals including some insects.

What is chromate aluminium coating?

Chromate conversion coating for aluminum and other types of metal is a chemical immersion process that is used to passivate and convert the surface properties of the substrate. The trivalent chromate conversion coating process provides outstanding corrosion resistance and conductivity, without any measurable buildup.

What is clear chromate?

Clear chromate is a chemical conversion coating that is applied over zinc plating during the surface coating process. Zinc plating is a soft, ductile, marginally solderable, corrosion-resistant finish. It protects the substrate and corrodes before the base metal, unlike most other commonly plated metals.

What is blue passivate?

Blue Passivate Most often when a drawing specifies ‘Blue’ they are most often actually referring to a Natural or Clear Finish. Any Passivation process will affect the colour of the component and there is no such thing as a completely clear or colourless finish.

What color is zinc finish?

The normal zinc-plated coating is dull gray in color with a matte finish, although whiter, more lustrous coatings can be produced, depending on the process or agents added to the plating bath or through post-treatments.

How do I remove chromate coating?

Older (cured) chromate can be removed with a caustic etch 100-150 g/l NaOH at 40 °C – 60 °C, followed by desmut in 50% nitric acid [credit Max Stein & Bill Grayson].

What color is chromate coating?

Chromate conversion coatings are commonly applied to everyday items such as screws, hardware and tools. They usually impart a distinctively iridescent, greenish-yellow color to otherwise white or gray metals. The coating has a complex composition including chromium salts, and a complex structure.

What color is chromate?

Zinc chromate, ZnCrO4, is a chemical compound containing the chromate anion, appearing as odorless yellow powder or yellow-green crystals, but, when used for coatings, pigments are often added.

What is trivalent coating?

Trivalent conversion coatings is used on metals such as aluminum and zinc, and to a lesser extent copper, cadmium, silver, tin, and other metals and their alloys. Trivalent conversion coatings are used to passivate aluminum and as a sealer on metal parts after an iron or zinc phosphate metal finishing process.

What is difference between trivalent and hexavalent zinc plating?

Trivalent zinc plating is the latest version of zinc plating. The ingredients that we use for this process are chromium sulfate or chromium chloride. On the other hand, hexavalent zinc plating is the older version of zinc plating. The ingredients that we use for this process are chromium trioxide and sulfuric acid.

What is blue chromate coating?

The blue is a slightly blue toned bright metallic finish, it is certainly not blue in the sense of blue paint. Traditionally these chromate coatings have involved hexavalent chromium. These days they are usually trivalent to comply with RoHS requirements.

What is the difference between clear chromate and zinc coating?

For extra corrosion protection, chromates are applied over this zinc coating. Clear chromate with zinc is a slightly iridescent blue color when complete, while yellow and black both give the respective colors to the finished part. We have two surface finish options that are chromate and do not contain zinc.

Is blue chromate plating hard to get your bearings?

A. “Blue chromate plating” is an example of somewhat misleading lingo or trade vernacular, Kevin, and it can indeed be hard to get your bearings in such cases. As a young engineer involved in surface finishing, please give strong consideration to attending a local AESF meeting (www.nasf.org) if possible.

What is the purpose of chromating?

The most common use for chromating is to impart corrosion resistance to zinc, zinc plated steel, certain steel alloys and some aluminum surfaces. Most chromated parts retain their electrical conductivity to varying degrees.

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