Are you currently searching for a corrosion-resistant and sturdy solution for titanium material? Then you may want to use the titanium anodizing process. It is worthwhile to learn about this procedure as it works effectively in improving the surface of titanium while providing it with an aesthetic look.
With that, it is no longer surprising to see it being used in many industries, among which are medical, aerospace, and automotive industries, which completely rely on anodized titanium because of the material’s proven reliability and strength.
This article supplies more relevant information about the titanium anodizing procedure, its benefits, best practices, and other useful details.
What is Titanium Anodizing?
Titanium anodizing can be defined as a surface finishing process that bolsters the material’s corrosion-resistance and durability, as well as the cosmetic look of products based on it. It also enhances the aesthetic appeal of the major anodized titanium components.
Expect this process to be really famous in industries that consider appearance and strength as vital, like aerospace and medical devices and materials. You can even see anodized titanium in CNC machining, specifically for precision components that need a polished look and a high level of functionality.
Another way to describe titanium anodizing is that it works as an electrochemical anodizing procedure, which aims to thicken the titanium surface’s natural oxide layer. It has a surface oxide film, which improves the durability and corrosion-resistance of metal, as well as its overall aesthetics and wear properties.
You can distinguish titanium anodizing from other surface finish options since it provides more precise control of the color and thickness of the protective oxide layer. This makes it suitable for various applications.
The titanium anodizing procedure involves immersing a piece of titanium in an electrolyte bath – after which, a direct current will be applied. The result is a vibrant and durable anodized titanium surface.
How Does Anodizing for Titanium Work?
Basically, the process of anodizing for titanium works by starting from its basic principle, which involves the use of an anodizing bath composed of an electrolyte solution, like sulfuric acid. Expect the titanium piece to act as the anode. Meanwhile, the stainless steel or aluminum serves as the cathode.
After applying direct current, it is highly likely that the electrolyte solution will begin facilitating the electrochemical reaction, which works in thickening the titanium surface’s protective oxide layer. The main goal of this process is to raise titanium’s resistance to wear, corrosion, and heat.
It helps form an anodized metal layer, which is completely integrated with the titanium material underneath and helps prevent chipping and flaking. You may also want to anodize titanium products, especially if you like them customized in several colors without the use of any other coatings.
Process Steps for Titanium Anodizing
Prior to doing titanium anodizing, it is advisable to obtain a deep and clear understanding of all the required steps to complete the entire process. This section explains the proven steps for titanium anodizing.
Step 1 – Cleaning and Preparation
As the name suggests, the first step connected to the process of titanium anodizing involves cleaning and preparing the metal surface. Here, you will have to cleanse the surface by removing grease, dirt, oil, and other contaminants with the help of an alkaline cleaner or degreaser.
Once done, use water to rinse the titanium and get rid of the traces of the cleaning solution. This is a vital step, as any residue found on the titanium surface may hamper the anodizing process and drastically affect the final product’s quality, especially its ability to withstand anodized titanium rust.
Step 2 – Etching (The Pre-treatment Phase)
Once you have completed the cleaning and preparation process, you must let the underlying titanium material go through another process called etching. Basically, it involves preparing an acid solution in which the metal can be placed.
In most cases, the solution is a mix of sulfuric and phosphoric acids. This is effective in taking a thin layer away from the surface. It also helps build a micro-roughened surface, which is more suitable for the anodizing process. In addition, etching eliminates all residual contamination that may be concealed from the surface.
Since the etching process serves as the pre-treatment phase, it is crucial to monitor it carefully, so you can attain your preferred titanium surface properties. You have to do this step as it assures you of the ability of the anodized titanium to achieve optimal performance. This is especially true if what it needs is specific titanium color anodizing.
Also, you have to rinse the etched titanium parts thoroughly to completely remove residual chemicals. This should prepare them for the next phase of the titanium color anodizing process.
Step 3 – Set Up for the Anodizing Process
Prepare the right concentration of electrolyte solution and put it in the appropriate vessel – one that is non-conductive while able to withstand the acid. It is also crucial to make the underlying titanium workpiece come in contact with the positive terminal, called the anode, as well as the cathode. Submerge them to prevent them from coming in contact with one another.
Step 4 – Anodizing
Now, it’s time for the most important step – the anodizing process itself. Basically, it involves the preparation of an electrolyte solution, which is often the sulfuric acid, and then immersing the titanium material there. It then needs the application of current to the metal.
The result of this process is an oxide layer growing on the titanium surface, which you can control by varying the voltage, process time, and current. It is also possible to control the layer’s color and thickness. What you should do to make that happen is to add dyes or pigments to the solution.
The length of time it takes to complete the anodizing process varies. It may go from just a few minutes up to a few hours. This will greatly depend on the anodized layer’s color and thickness.
Step 5 – Rinse and Dry
Once the anodizing process is over, you should take the titanium workpiece out of the electrolyte bath. You should then use distilled water to give the titanium a more extensive rinse. This gets rid of remaining residues that may negatively affect the final titanium oxide layer or coat. When it comes to drying, you are allowed to use compressed air. You may also just leave it to dry naturally in the open air.
Step 6 – Sealing (optional)
This optional step requires putting the workpiece within a sealing bath, which contains either a sealing agent or hot water. You need to leave it in the solution as it allows the proper hardening of the oxide layer formed. It helps improve the anodizing’s depth and surface characteristics.
Step 7 – Post-treatment
This is the step where quality control and inspection will be conducted. What you should do is examine and inspect the anodized titanium under sufficient illumination to detect immediately if there are defects and irregularities. It is also crucial to test it for titanium color anodizing consistency and thickness.
All non-conformities and irregularities should be corrected. In addition, it is important to clean and dry the final product thoroughly. This step helps ensure the excellent performance and quality of anodized titanium and guarantees high customer or client satisfaction.
Where is Anodized Titanium Used?
The enhanced aesthetic appeal and surface properties of anodized titanium are among the major reasons why it is used across different industries. The process enhances corrosion resistance while creating an oxide layer with a great visual appeal. With that, expect the titanium parts to become really suitable for many applications.
The following are just a few of the many key applications and industries where you can see anodized titanium:
Aerospace components, including aircraft parts, fasteners, and turbine blades, as anodized titanium can provide those with lightweight durability and corrosion-resistance
Medical industry as it has biocompatibility, which makes it suitable for surgical instruments and implants, as well as prosthetics
Jewelry, such as rings, earrings, and bracelets, since it provides different titanium color options ideal for decorative purposes
Automotive industry since it can improve the durability of auto parts, like engine parts, exhaust systems, and suspension components while boosting their ability to resist anodized titanium wear and tear
Consumer electronics, like smartphone cases, laptop housings, and connectors, because the anodized titanium gives those items an aesthetic finish
Architectural elements since the titanium anodization can result in a product that can increase the durability and visual appeal of building facades, structural elements, and roofing panels
Sports equipment as it improves their performance, such as golf clubs and bicycles
Marine applications with the superior corrosion-resistance of anodized titanium – This makes the product ideal for boat fittings that may acquire corrosion from constant exposure to seawater.
Eyewear since anodized titanium is perfect for frames because of its sturdy and lightweight nature
Energy sector as the conductive properties can help in batteries and fuel cells
Arts and sculpture – The reason is anodized titanium can give artistic projects a durable and vibrant finish.
Watchmaking, giving watch components a high level of durability and different colors
The Benefits of Titanium Anodizing
Titanium anodizing can definitely be defined as a process, which can lead to the manufacture of a versatile material that benefits CNC machining designers. It is also possible to leverage anodized titanium in a way that creates visually appealing and functional products.
Any CNC machining designer can incorporate anodized titanium into their design in order to produce sustainable and durable products that also show unmatched style and sophistication.
The following are just a few of the benefits of titanium anodization that truly make it impressive:
Lightweight
One fact about the typical titanium material is that it has really lightweight properties, so it is a good material for products that need a higher-than-usual strength-to-weight ratio. Expect anodized titanium to be even lighter compared to the regular titanium. The reason is that it has a thin oxide layer on the surface.
The fact that it is really lightweight makes it the best material for the manufacture of products that need superior durability and strength without the extra weight. Among these are electronics, aerospace parts, and sporting goods.
Aesthetically Pleasing
The aesthetic appeal of anodized titanium is also unquestionable. This specific material has various colors and finishes that you can customize to fit your design needs and requirements. There is also a high possibility for the titanium anodizing procedure to allow the making of different colors, including vibrant colors and subdued tones.
You can use this wide variety of colors to make your products more visually appealing. Anodized titanium can also provide different finishes, such as glossy, textured, and matte, that you can use to give your designs more dimension and depth.
Highly Durable
Another remarkable benefit of anodized titanium is its high level of durability. The anodizing process produces a wear-resistant, solid, and hard oxide layer on the surface, further enhancing wear-resistance and the durability of the typical titanium material. As a result, it is highly likely for it to resist wear and tear, dents, and scratches.
This benefit is also one reason why anodized titanium is specifically useful for products subject to constant exposure to harsh environments, as well as rigorous and constant use, like aerospace components, medical tools and devices, and industrial machinery.
Environmentally Friendly
You are also assured of the environmentally friendly nature of anodized titanium, which increases its safe use in a wide range of applications. What’s great about the entire titanium anodizing process is that it is basically non-toxic.
It will not emit harmful vapors or chemicals into the environment, so it is definitely an eco-friendly and sustainable option. It is also recyclable, making it useful for minimizing waste and carbon footprint.
Corrosion-resistant
The excellent corrosion-resistance of anodized titanium also makes it an incredible choice for a lot of products and applications. Basically, the anodizing process serves as the barrier capable of protecting the titanium material from corrosion, which often happens when it gets exposed to some environmental factors, chemicals, and moisture.
This particular benefit is one reason why anodized titanium is suitable for use in environments that expose objects to harsh chemicals and corrosion. Examples include automotive components, marine equipment, and chemical processing equipment.
Biocompatible
Another impressive advantage of anodized titanium is that it is proven to be non-toxic plus known for its biocompatibility. This is the reason why it is an incredible choice for many medical applications. You can see anodized titanium implants, surgical instruments, and prosthetics being widely used in the medical field since they are proven to be compatible with the human body and can also resist bodily fluids.
The Limitations of Titanium Anodizing
One important fact about titanium anodizing, though, is that even if it has plenty of benefits, it also comes with its own set of limitations and challenges. Here are just a few things to watch out for as they serve as drawbacks of anodized titanium:
High initial cost
Anodized titanium is famous for its durability and longevity, which is the reason why it is truly cost-effective if you look at it on a long-term basis. Note, though, that its initial cost is high – the titanium material and the entire anodizing process can get really costly. This specific problem may pose limitations on its use in specific applications.
Requires a high level of skills
The titanium anodizing process needs a high level of expertise and a thorough understanding of all factors and parameters linked to it. If you don’t have the right skills and knowledge, you will have a hard time attaining your desired results. It is also highly likely that the final product will be defective and inconsistent.
For instance, it is important to have precise and full control of electrical parameters, including current and voltage. Any variation may result in an inconsistently thick oxide film. It is also possible for the color anodizing process to cause discrepancies in terms of color.
Also, you have to be an expert when it comes to temperature changes. The reason is that titanium is highly sensitive to any change in temperature. If you don’t know how to handle the fluctuation or change, then it is possible for it to affect the final surface finish and the uniformity of the oxide layer.
Poses challenges in surface preparation
As you may have known by now, the anodizing process starts by preparing the surface. One fact about titanium is that it is capable of forming a passive oxide layer on the surface that serves as protection against corrosion. It is also the specific element that makes it difficult for the anodizing solution to bond or get attached to the surface.
This problem can be overcome by using a strong and vigorous acid wash, which aims to get rid of the surface’s passive layer. This can contribute to the solution bonding with the surface of the titanium material in a more effective manner.
Challenging thickness specifications
It is quite hard to obtain the exact thickness that the anodizing process requires. Even minor differences may affect the result. In some cases, you can’t expect these minor differences to matter a lot, but there are also several instances where it is a must to be absolutely precise; otherwise, it may cause a problem.
To make it easier to understand, take note that if you anodize titanium, you will have to use 20 to 100 volts. This is the range of voltage that you will have to play with. With that in mind, expect a 20-voltage setup to provide a light-yellow result. Meanwhile, a 100-volt set-up can give you dark blue.
Note that these colors are derived from the specific thickness of the anodized layer. To be more specific, light yellow has an oxide layer thickness of around 30 nanometers while dark blue is usually 150 nanometers.
Prone to inconsistency in colors
One thing to note about titanium anodizing is that it tends to produce color via light interference. This makes it kind of challenging to get a consistent shade. Expect this titanium color to depend on the specific oxide layer thickness, which also relies on how precise your control is on the key parameters of the anodizing process, including temperature and voltage.
Titanium Anodizing Versus Aluminum Anodizing
Aside from titanium, you can also anodize aluminum. Comparing both processes, though, requires you to consider a few unique factors and situations. Yes, the two can improve the metal’s corrosion-resistance but they are also different in terms of the mechanism they use to generate colors.
For instance, instead of dyes, titanium anodizing gets its desired color through light interference, which also gives it lasting vibrancy. Meanwhile, aluminum anodization can lead to thicker protective layers compared to titanium. It is also known for being less energy-intensive compared to anodized titanium.
Other known differences between the two include the following:
Thickness of coatings
Anodized aluminum usually has a thicker oxide layer compared to anodized titanium. The reason behind this is the ability of aluminum to form an oxide layer naturally once it gets exposed to air.
Letting it go through the process of anodizing can further boost this ability. The fact that it has a thicker layer makes anodized aluminum effective in specific applications that need extreme wear-resistance, such as heavy-duty automotive parts and industrial machinery.
Corrosion-resistance
Another difference between titanium and aluminum anodizing is their level of corrosion resistance. Titanium is actually superior to aluminum in this area. Despite having a thinner oxide layer, anodized titanium can still be expected to deliver a higher level of corrosion-resistance compared to anodized aluminum.
The reason is that the oxide layer formed in titanium is proven tough and sturdy while providing a high level of protection from harsh conditions. This enhanced corrosion-resistance is the reason why you can now widely see this material in highly demanding and rigorous marine and aerospace components applications.
Required process temperatures
In terms of process temperature, the one required by the titanium anodizing process is usually higher compared to that of aluminum. Higher temperatures can lead to the consumption of more energy plus the increased possibility of wear on the anodizing tool.
Dye color options
When it comes to your options for dye color, expect the number to be higher in aluminum. There is a more extensive color spectrum in anodized aluminum because it is capable of incorporating dyes into the entire process.
Note, though, that the varied and vibrant colors you can see in anodized titanium are caused by the light interference derived from the thickness of the oxide layer. Dyes can’t influence them, too.
Aesthetic appeal
The anodizing process is actually capable of providing a lot of finishes and colors to the object’s surface. You can even expect both aluminum and titanium materials to be anodized in various colors. However, titanium is known to provide a more extensive line of finishes and colors.
The reason is that the titanium anodizing process can create iridescent and vibrant colors that are impossible to see in aluminum anodizing. You can also polish it in a way that will give a mirror-like finish, thereby producing a premium feel and look. Meanwhile, aluminum anodizing is more appropriate for use when planning to create a more natural metal look or matte finish.
Cost
There are actually several factors that affect the anodizing cost – among which are the object’s size, desired finish, and quantity. In general, titanium anodizing is costlier compared to aluminum anodizing. The reason is that the titanium material is more challenging and harder to work with compared to aluminum.
Titanium also needs expertise and specialized equipment to get your desired results. Meanwhile, aluminum anodizing requires a simpler process, which is why you can also do it at a lower cost.
Titanium Anodizing Best Practices
Now, it’s time for you to learn about the best practices necessary for titanium anodizing to ensure that the process will give you optimal results.
Do the surface preparation process carefully
Note that anodizing can produce successful and great results if you do proper surface preparation. Be very thorough in cleaning the parts of the titanium. The entire material should not have any dirt, oil, or oxide layers. Also, it is advisable to combine the use of chemical treatments and abrasive cleaning to guarantee the oxide layer’s optimal adhesion.
Keep complete control of the bath temperature
The bath temperature should stay consistent throughout the anodizing process. It would be better to stick to the ideal temperature, which is around 18 degrees to 22 degrees Celsius. It is crucial to stick to this as any fluctuation may lead to an inconsistent oxide layer, which can have a drastic on the final product’s overall appearance and performance.
Monitor current and voltage
Controlling current and voltage precisely is vital for both aluminum and titanium anodizing. Use a constant and reliable power supply when controlling the current and voltage during the whole anodizing process to guarantee safe, quick, and consistent results. It helps in attaining uniform color consistency and oxide layer thickness.
Be extra careful when handling chemicals
Adhere to all safety guidelines as you handle chemicals, like sulfuric acid and hydrofluoric acid, during the anodizing process. It helps to use the right tools and containers when handling such chemicals to prevent spills.
Optimize the thickness of the oxide layer
Take full control of the thickness of the oxide layer based on the intended and desired application of the part. If it is intended for applications that require a high level of durability, like in military or aerospace, then it is ideal to go for Type 3 or thicker oxide layers. Meanwhile, decorative applications require Type 2 or thinner layers.
Conclusion
Titanium anodizing is indeed a process that can help improve the appearance, aesthetic appeal, and overall durability of titanium parts. With its ability to create a sturdy and robust oxide layer, it can give such parts exceptional wear protection and corrosion-resistance.
However, you have to make sure that you test the anodized parts regularly to maintain their quality. Conduct tests regularly, such as for corrosion-resistance, thickness measurement, and color consistency to guarantee that they comply with the standards in the industry.
Visual inspection is necessary so you can identify defects as early as possible and correct them immediately. With that, you are guaranteed the anodized titanium’s quality, making it more useful and valuable in industries that need a high level of performance and precision.