Black Oxide Coating: Process and Applications - Black Oxide Services
Black Oxide coating is a type of chemical coating applied to metals, especially iron and steel, to increase their resistance to corrosion. In this process, the metal surface reacts with chemicals, forming a thin layer of iron, usually magnetite (Fe₃O₄), on the surface. There are various methods for applying black oxide coating, each with its own advantages, which we will discuss further below
Black Oxide Services
Sakht Pooshesh Company, with decades of experience and expertise in providing black oxide services on both large and small scales, is one of the leading companies in the field of black oxide coating in Iran. By utilizing a specialized team alongside global knowledge and modern expertise, we ensure high-quality black oxide coating and hardening of various industrial parts. Furthermore, you can directly contact our specialists if you have any questions
Black oxide coating is commonly used to increase the resistance of iron and iron alloys, enhancing their performance in specific and sensitive conditions. It helps to prevent surface damage and friction
Advantages of Black Oxide Coating
This method imparts the following properties and characteristics to the metals on which the process is applied, enhancing their performance and efficiency.
Increased Resistance: The main property that black oxide coating provides is increased resistance. In this chemical process, no material is added to the metal surface, but through the chemical process, the metal itself forms a layer of oxide on its surface, which enhances resistance.
Maintaining Part Dimensions : Most coating processes, such as hard chrome plating, are coating processes that increase the part’s thickness. However, the black oxide process does not increase the thickness of the part significantly, adding only between 0.5 to 2.5 micrometers to its thickness.
Increased Thermal Resistance : In addition to mechanical resistance, black oxide coating enhances the thermal resistance of parts, ensuring that no damage occurs at very high temperatures. The part retains its mechanical properties even with temperature fluctuations.
CostEffectiveness : There are various methods for coating, each with its specific applications. This method is one of the most economical and cost-effective, offering high resistance while being affordably priced.
Sample of Black Oxide Coating by Sakht Pooshesh
Sakht Pooshesh Company is recognized as one of the leading companies in the field of black oxide coating, carrying out this process in compliance with international standards such as Mil-DTL-13924D.
Methods of Black Oxide Coating
Hot Black Oxide
Mid-Temp Black Oxide
Cold Blackening
In the following, let’s discuss and review each of these methods from the website of Sakht Pooshesh, the leading provider of black oxide services in Iran. Each of these methods is suitable for specific parts and processes.
High-Temperature Black Oxide : This is the most common and widely used black oxide coating process, and it is typically suitable for steel. In this method, the temperature can range from 285°C to 295°C. The high temperature helps create a uniform and consistent coating, resulting in a high-quality appearance.
Mid-Temperature Black Oxide : The reason for using this method instead of the high-temperature process is to reduce the risks associated with high temperatures while improving efficiency and productivity. The temperature range in this method depends on the company performing the process and the specific formula used.
Low-Temperature Black Oxide : This process is performed at lower temperatures, and the black oxide chemical reaction does not occur with high quality. As a result, it does not have the same adhesion and bonding strength as the first method. Therefore, this method is typically used for standard, workshop, and sometimes decorative applications.
Stages of Black Oxide Coating
This chemical process requires specific stages to be followed in order to achieve maximum effectiveness, efficiency, and performance, ensuring the highest quality black oxide coating on parts. In this section of the Sakht Pooshesh website, we will review these stages.
- Cleaning with Detergents: In this stage, the part is thoroughly cleaned with chemical detergents to remove any excess materials and surface oils, ensuring that the black oxide coating will adhere properly and effectively during the next stages
- Washing with Water: In this stage, the part is completely washed with water to remove any detergent residues from the first step, ensuring the surface is completely clean and prepared for the coating process
- Oxidation Bath: The part is placed in a bath of alkaline oxidizing materials at a specified temperature, allowing the black oxide layer to form on the part. This process is carried out according to the standards and formulas of each company, and it is the most crucial and important stage of the black oxide process
- Sealing with Oil: In this stage, to enhance the resistance and quality of the oxidation, the part is placed in special oils. This process improves both the mechanical properties of the part and the quality of the black oxide coating on the surface
- Final Inspection: Finally, the parts are inspected both visually and systematically to ensure that the black oxide coating has been applied properly
Applications of Black Oxide
Aerospace Industry
Automotive Industry
Tools and Equipment
One of the most important applications of black oxide is in the aerospace and aircraft manufacturing industries
Disadvantages of Black Oxide Coating
Limited to Certain Metals : This process is applied to specific metals such as iron and steel and is not suitable for other metals like aluminum, copper, and others.
- Vulnerability to Scratches: The coating may be damaged or peeled off from the surface due to scratches or impacts
- Low Resistance to Strong Acids: The coating may corrode when exposed to strong acids or humid environments
