Anodizing Types – Eloxal (E0–E6) & Type I–III
There are two main anodizing classification systems: the European Eloxal (E0-E6) and the American Type I-III.
On this page, we will explain how they relate to each other, how they differ, and which type is best suited for your project.
What is Eloxal Anodizing
Eloxal (from Elektrolytische Oxidation von Aluminium) is a European approach to anodizing that focuses on the appearance and surface quality of aluminum.
The word Eloxalverfahren means “electrolytic oxidation of aluminum” - a process that combines metal protection with a decorative effect.
Eloxal anodizing is divided into classes from E0 to E6, each serving a different purpose - from technical to decorative.
Eloxal Classes (E0-E6)
| Class (Eloxal) | Description | Surface Type / Treatment | Main Application |
| E0 | Technical anodizing | Matte, unpolished | Industrial parts, housings |
| E1 | Matte finish | Mechanical or chemical matting | Architectural profiles |
| E2 | Chemically bright | Chemical polishing before anodizing | Decorative panels |
| E3 | Mechanically bright | Polishing with brush or paste | Home appliances |
| E4 | Colored anodizing | Coloring after anodizing | Design, architecture |
| E5 | Hard anodizing | Thick, wear-resistant layer | Aviation, automotive, tools |
| E6 | Mirror-decorative | Glossy, colored coating | Lighting, interiors, advertising |
More about hard anodizing: Hard Anodizing
Decorative coatings: Colored Anodizing
Types of Anodizing (Type I-III)
The American classification Type I-III describes the type of electrolyte and the thickness of the protective layer.
It is widely used in manufacturing, mechanical engineering, electronics, and other technical applications.
| Type | Electrolyte | Layer Thickness (µm) | Characteristics |
| Type I | Chromic acid | 3-10 | Thin layer, good corrosion resistance |
| Type II | Sulfuric acid anodizing | 5-25 | Most common; decorative and technical finish |
| Type III | Chilled sulfuric acid anodizing | 25-150 | Hardcoat anodizing with high wear resistance |
How to Choose the Right Type of Anodizing
The choice depends on what matters most for your product - appearance, protection, or wear resistance.
| Purpose | Recommended Type | Explanation |
| Protection and corrosion resistance | Type II / E0-E2 | Optimal balance between durability and appearance |
| High wear resistance | Type III / E5 | Thick layer with increased hardness |
| Decorative effect | E4 / E6 | Colorful, glossy coatings |
| Technical applications | E0 / E1 | Matte, functional finish |
Eloxal and Sulfuric Acid Anodizing
Most Eloxal anodizing processes are based on sulfuric acid anodizing, which corresponds to Type II in the American system.
The difference lies in focus:
- Eloxal - emphasizes visual and aesthetic quality.
- Type II - focuses on technical classification by electrolyte and layer thickness.
Anodizing with Topanod
Topanod offers a full range of anodizing services - from technical to decorative coatings:
- Eloxal E0-E6 for architectural and design solutions.
- Type I-III for industrial and technical products.
- Full control over coating thickness, color, and surface finish.
Order Anodizing for Your Project
Looking for reliable aluminum anodizing with precise parameters and consistent quality?
We’ll help you choose the optimal coating type for your needs