Exploring Black Oxide Coating Advantages And Types
A popular industrial method, black oxide coating is a common conversion coating applied on ferrous metals and different manufactured components for smooth finishings and a rich look. The coating forms a protective layer and adds to the surface’s durability, shine, and corrosion resistance.
Usually, coatings of black oxide are applied to machine parts, carbon steel parts, fasteners, tools, and other precision components to prevent them from corrosion and make them visually pleasing. These coatings have gained much popularity for their waterproofing properties and are mixed with oils and waxes for an even smoother and shinier finish.
Understanding The Black Oxide Coating Process
In the manufacturing industries, different types of metals are used for making machine parts, tools, precision parts, and many other small and big components. However, to make these metal components more durable, popular methods like black oxide coating are introduced to make the surface of manufactured parts more durable, shining, smooth, and aesthetic.
In other words, it offers a high-performance coating that reduces the chances of chipping and rust. It is necessary to understand the process before choosing black oxide coatings for your manufactured parts.
In the process of coating metals with black oxide, the metals or manufactured parts are bathed in a black liquid that combines sodium hydroxide, nitrates, and nitrides. The temperature of the liquid is controlled, depending on the coating process chosen, and further, the parts are dipped in alkaline cleaners, water, and sealant solutions (mainly oil). The process of coating is commonly followed by high-tensile fastener manufacturers, automotive part manufacturers, precision component manufacturers, and many more.
The Purpose Of Black Oxide Coating
In the black oxide coating process, the primary purpose is to make metal parts corrosion-resistant and offer a smooth finish and aesthetic look, but deep down, there are a few more critical reasons that serve the purpose of coating. The other purposes of this coating are:
- Minimizing light reflection
- Offering a uniform finish to the parts
- Increasing durability and wear resistance
- Provides mild lubrication for enhanced component performance
- Improves adhesion of paints and other types of coatings
- Provides a cost-effective coating solution
- Increases resistance to abrasion and scratching
- Enhances electrical conductivity of metal surfaces
5 Benefits Of Black Oxide Coating
It provides many advantages when it comes to high-tensile fasteners. This inexpensive method has multiple attached in between the protective coatings and plating processes.
Enhanced Surface
Finish coating metals with black oxide offers a smooth surface finish that is shiny and scratch-resistant. The smooth surface also elevates the look of the machine parts and makes them more visually pleasing.
Additional Resistance
Black oxide coating enhances the finishing and look of metals, but it also adds additional resistance. Metals coated with black oxide have more corrosion and wear resistance.
Rich Look
The matte black finish obtained after coating metals adds a rich look to the manufactured parts.
Increased Lubricity
For further manufacturing processes, many machine parts are required to be lubricated. It ensures the machine parts have improved lubricity. As black oxide coating finishes are always made with wax or oil, this, too, adds to the lubricating effect.
Reduced Light Reflection
One of the best benefits of coating metals with black oxide is reduced reflection. Usually, the reflection caused by metals is distracting and can sometimes lead to eye fatigue. Coatings with black oxide give metal surfaces a matte surface that does not reflect light.
Different Steps Involved In The Black Oxide Coating Process
This is a step-by-step process, that is handled carefully to achieve a shiny, matte black surface finish.
Step 1: Alkaline Cleaning
The process of black oxide coating begins with alkaline cleaning, where the metal parts to be coated are cleaned with an alkaline solution to remove all the impurities. This step is vital to remove all that oil and grease build-up from metal parts.
Step 2: Rinsing With Water
After cleaning thoroughly with the alkaline solution, the metal parts are rinsed and washed in water. The rinsing of the metal also prepares it for the next step, dipping in black oxide.
Step 3: Black Oxide Immersion
The third step is vital in the coating process as the metal parts are finally immersed in a hot bath of black oxide solution. The solution then reacts with the metal and forms a coating over the parts.
Step 4: Rinsing With Water Again
After the immersive bath, the metal parts are rinsed in water to cool them and seal the coating.
Step 5: Final Touch Up
The final step involves adding a final touch-up by polishing the surfaces with oil or wax to offer a shiny and smooth finish.
Types Of Black Oxide Coating Methods
Coming to the different black oxide coating types, three of them deserve a mention.
Hot
In this process, the metal parts are coated with black oxide at a high temperature of 286 °F (141 °C). The hot solution reacts with the surface of the metal and forms a thick black coating. The metal parts are further rinsed in water to cool, remove any remaining solution, and seal the coating.
Cold
The opposite of the hot black oxide process, in the cold black oxide process, the metal parts are dipped in a solution with a maintained temperature range similar to room temperature instead of the high-temperature solution. The coating process takes place between 68 °F to 86 °F (20 °C to 30 °C).
Mid-Temperature
This method maintains a temperature substantially lower than the hot black oxide process. The temperature of the black oxide solution should be maintained between 200° to 210° F (93°C to 98°C).
Choosing Black Oxide Coated Components From A Reliable Manufacturer
If you seek reliable precision components in India that manufacture machine parts with traditional coating methods, then Bhansali Techno Components is your one-stop solution. From high tensile bolts to precision and CNC-turned components, partnering with a reliable manufacturer like Bhansali Techno Components ensures you access to high-quality machine parts with quality assurance.
