Clear Chromate

2024-08-08 Cherry 

Introduction

In modern manufacturing, the combination of die-casting

machines and surface treatment technology have brought

products with higher quality and performance. Among them,

clear chromate, as an excellent surface treatment method,

is increasingly used in die-casting products. This article will

explore the characteristics of clear chromate and its

application in die-casting products in depth, aiming to help

readers fully understand this technology and improve the

quality and market competitiveness of related products.

Basic knowledge of Clear Chromate

What is clear chromate?

Clear chromate is a colorless or light-colored surface

treatment agent that forms a dense chromate film on the metal

surface through chemical conversion. This film has good corrosion

resistance, high transparency, and strong adhesion.

It will not affect the original appearance of the metal, and can

further improve the corrosion resistance and aesthetics of

the product. This treatment method is suitable for a variety

of metal die-casting products, including magnesium alloys,

zinc alloys, and aluminum alloys.

The main components of clear chromate

The clear chromate treatment solution usually contains

a mixture of hexavalent chromium and trivalent chromium,

as well as other auxiliary chemicals. These components form

a protective film on the metal surface through chemical

reactions to improve the metal's corrosion resistance and

wear resistance.

Technical features of transparent chromate

1. Excellent anti-corrosion performance

The metal surface treated with clear chromate has

extremely high corrosion resistance. The chromate film can

effectively prevent oxidation and chemical corrosion,

and extend the service life of metal products.

2. High transparency

The clear chromate treatment does not change

the original color and gloss of the metal, and maintains

the beauty of the metal surface. This is especially

important for some products that require a high appearance

quality, such as decorative parts and electronic product housings.

3. Good adhesion

The clear chromate film has strong adhesion to the metal

substrate and is not easy to peel off or delaminate.

This ensures that the product can still maintain good

protective effect during long-term use.

4. Environmental performance

Compared with traditional hexavalent chromium treatment,

clear chromate uses more trivalent chromium, which

reduces pollution to the environment and meets modern

environmental protection requirements. This makes

clear chromate a more green and environmentally

friendly surface treatment technology.

Application of clear chromate in die-casting products

Surface treatment of die-casting parts

Die-casting parts are often exposed to high temperatures,

high pressure and corrosive environment during the production

process. Through clear chromate treatment, a dense

protective film can be obtained on the surface of die-casting

parts, effectively improving their corrosion resistance

and service life.



1. Magnesium alloy die castings: Due to the low corrosion resistance

of magnesium alloys, chemical anti-corrosion treatment, and

surface spraying is required. Anti-corrosion treatment is

usually carried out in chromate and phosphate passivation

to passivate and anodize to improve the corrosion resistance

of magnesium alloys and enhance the adhesion of the spray layer.

Commonly used coatings include epoxy resin, vinyl resin,

polyurethane, etc.1. ‌

2. Zinc alloy die castings: Zinc alloy die castings are

susceptible to corrosion, which affects the appearance

and mechanical properties. By directly performing chromate

passivation treatment on zinc alloy die castings, an excellent

passivation film can be obtained, which improves the corrosion

resistance of the product and meets the precision requirements

of dimensional matching in industries such as automobiles. ‌

3. Aluminum alloy die castings: After sandblasting, aluminum

alloy die castings can be directly chromate to obtain a colorless

to yellow passivation film, which does not affect the surface

resistance and meets the three-proof requirements of the product.

After chromate treatment, spraying can also be performed to

achieve better protection and aesthetic effects. 



Automotive parts

Automotive parts such as engine housings, gearbox housings

and various connectors often need to withstand harsh operating

environments. Transparent chromate treatment can significantly

improve the corrosion resistance of these parts while maintaining

their original appearance quality and mechanical properties.

Electronic product housings

Electronic product housings require high aesthetics and

durability. Clear chromate treatment not only provides

excellent corrosion resistance, but also maintains the gloss

and beauty of the metal surface, meeting the appearance

requirements of high-end electronic products.

Household appliances

Household appliances such as washing machines, refrigerators,

microwave ovens, etc., also require anti-corrosion treatment

for their metal parts. Transparent chromate treatment

can effectively improve the durability and reliability

of these products and extend their service life.

Process flow of clear chromate treatment

Surface pretreatment

Before clear chromate treatment, the metal surface

needs to be pretreated, including degreasing, rust removal

and cleaning. These steps can remove dirt and oxide layers

on the metal surface and ensure the adhesion of the chromate film.

Chromate treatment

The pretreated metal parts are immersed in a clear chromate

the solution to form a dense chromate film through

a chemical reaction. The treatment time and temperature

should be controlled according to the specific process

requirements to ensure the quality and performance of

the film layer.

Post-treatment

After the clear chromate treatment, the metal surface

needs to be cleaned and dried to remove excess chemicals

and residual liquid. If necessary, a sealing treatment

can also be performed to further improve the corrosion

resistance of the film layer.

Advantages and challenges of clear chromate treatment

Advantages

1. Efficient anti-corrosion: The clear chromate

film has excellent anti-corrosion performance and can

significantly extend the service life of metal parts.

2. Environmental protection: Clear chromate uses more

trivalent chromium, which reduces pollution to the environment

and meets modern environmental protection standards.

3. Maintain appearance: Clear chromate treatment does

not change the original appearance of the metal and is suitable

for products with high appearance requirements.

4. Good adhesion: The chromate film has strong adhesion to the

metal substrate and is not easy to peel off or delaminate.

Challenges

1. Process control: Clear chromate treatment requires

precise control of process parameters, including treatment

time, temperature, and chemical composition, to ensure the

quality and performance of the film layer.

2. Cost: Compared with traditional surface treatment methods,

clear chromate treatment may increase certain costs, and

cost-benefit analysis needs to be conducted in actual applications.

Conclusion

As an advanced surface treatment technology, clear chromate

has been widely used in die-casting products due to its excellent

anti-corrosion performance, high transparency, and environmental

protection performance. Through the introduction of this article,

it is hoped that readers can fully understand the technical

characteristics of clear chromate and its application

in die-casting products, reasonably select and apply this

technology, and improve the quality and market competitiveness

of products.

If you have any questions or needs about clear chromate

or die-casting machines, please feel free to contact us,

we will wholeheartedly provide you with professional technical

support and services.

For more info, you can refer to: https://www.youtube.com/shorts/JLX410QV_kw

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