What is the difference between hard chrome plating and decorative chrome plating?

Hard chrome plating generally uses more machinery that is often used under high temperature conditions, such as molds.

As the name suggests, decorative chrome plating is mainly for bright surface, beautiful appearance, rust prevention and so on.

Determine which chrome to use according to its purpose

1. The relationship between chromic anhydride concentration and hardness

When other process conditions are the same, the hardness is high when the chromic anhydride concentration is low. But the concentration is low, the plating solution changes quickly and is unstable.

2. The relationship between sulfuric acid content and hardness

In normal chrome plating process specification. The ratio of chromic anhydride to sulfuric acid should be kept at 100:1. When other concentrations remain unchanged, increasing the content of sulfuric acid will increase the hardness of the chromium layer accordingly. However, when the ratio of the two is 100:1.4, the hardness value will decrease when the sulfuric acid content is increased.

Decorative chrome

3. The relationship between current density and hardness

At normal temperature, the hardness of the chromium layer increases with increasing current density. When the current density reaches a certain limit, the hardness tends to be stable.

4. The relationship between the stability of the chrome plating solution and the hardness

At higher temperature (65-75°C), the hardness of the chromium layer plated from dilute solution is 15-20% higher than that of the chromium layer plated from concentrated solution; at lower temperature (35-45°C), The hardness of the chromium layer plated from the dilute solution is not much different than that of the chromium layer plated from the concentrated solution.

5. The relationship between the thickness of the chrome plating layer and the hardness

Generally, the hardness of hard chrome plating increases with the increase of thickness, and the highest value of hardness is about 0.2mm. In the future, even if the thickness is increased, the hardness will not increase.

6. As the heating temperature increases, the hardness of the chromium coating decreases significantly.