There are some differences in thickness ranges and characteristics between different types of chromium plating, such as trivalent chromium and hexavalent chromium. Here is a comparison of the two types of chromium plating:

1. Hexavalent chromium plating
Recommended thickness: Usually between 5-25 microns.

Characteristics:
Corrosion resistance: Hexavalent chromium plating has good corrosion resistance and wear resistance and is commonly used in automotive, home appliances, and tools.
Gloss: Provides high gloss and decorative effects, suitable for applications that require beautiful appearance.
Environmental impact: Hexavalent chromium is considered toxic and potentially harmful to the environment and health, so its use is restricted in many countries and regions.

2. Trivalent chromium plating
Recommended thickness: Usually between 1-20 microns.

Characteristics:
Corrosion resistance: Trivalent chromium plating has relatively good corrosion resistance, but generally not as good as hexavalent chromium plating. Its wear resistance is also moderate.
Gloss: Trivalent chromium coatings usually have a lower gloss and are not as bright as hexavalent chromium coatings, but the gloss can be improved through post-treatment.
Environmentally friendly: Trivalent chromium is considered a more environmentally friendly choice because it is less toxic and suitable for use in environmentally stringent applications.

Summary
Thickness range: Hexavalent chromium coatings have a wider thickness range, usually required between 5-25 microns, while trivalent chromium coatings are generally thinner, usually between 1-20 microns.
Selection basis: When choosing the type of chrome coating, it is necessary to weigh corrosion resistance, wear resistance, appearance requirements and environmental factors. For applications that require high corrosion resistance and gloss, hexavalent chromium coatings may be preferred; while in places where environmental protection and safety are important, trivalent chromium coatings will be a better choice.
In actual applications, it is recommended to conduct a detailed evaluation and selection based on specific needs and standards.