How to make titanium metal products look beautiful depends on a variety of surface treatment techniques. This article will list the 7 major surface treatment processes for titanium metal and see what you know!

1、 Anodizing

Anodizing, as a well-known and mature process, will not be further introduced here. In addition to commonly used aluminum alloy anodes, titanium metal can also be used as an anode, and most of the coloring processes for titanium are achieved through anodizing, which can create more diverse colors and patterns, with significant differentiation, including various options such as ice crystal flowers and threads.

In addition to decorative purposes, the anodizing process also plays a role in forming a dense film layer on the metal surface of the product, enhancing mechanical properties, wear and weather resistance, insulation, and improving the adhesion with the coating.

It is worth mentioning that titanium alloy is different from aluminum alloy. Although the cost of using titanium as an anode is higher, the hardness of the oxide film formed by titanium alloy is even worse than that of itself. So, generally speaking, many manufacturers choose to use anodes on the surface of pure titanium products. For example, the products in the picture all have an anode effect on the surface of TC4 pure titanium material.

Most titanium products are colored using anodizing technology, but later require some surface processes for protection. For example, in the iPhone 15 Pro, except for the original titanium silver color, the other three colors (black, white, and blue) are all colored using anodizing technology. Subsequently, PVD achieves functional protection.

2、 PVD coating

PVD, also known as physical vapor deposition, is a mature process for vacuum coating. PVD coating on the surface of titanium alloy is possible, mainly by adding functional coatings to provide protection and protection. However, it is worth noting that currently PVD can only barely pass the level of functionality, and durability still needs to be improved, unless the performance of PVD's primer material is very good.

Taking the iPhone 15 Pro as an example, among the four color schemes: black titanium, white titanium, blue titanium, and natural titanium, except for the original titanium silver color, the other three color schemes are combined with PVD coating technology on the anode basis to increase the surface performance of the product. However, there were still adverse effects such as fading in the future, which reflects the shortcomings of PVD in durability.

Of course, in addition to functionality, coloring effects can also be achieved. Overall, it can greatly enhance the design level of the product.

III CNC

CNC machining of titanium alloys mainly serves the functions of shaping and refining. One of the major issues in the machining process is the wear and tear of cutting tools. Because titanium alloy is relatively hard, the processing difficulty is higher compared to other metals. During the machining process, the tool is subjected to high temperatures, large cutting forces, long friction distances, significant vibration and deformation, and sticking to the tool, resulting in severe tool wear. Traditional cutting tools are difficult to machine titanium alloys, and special composite coated tools, even diamond and CBN tools, must be used for better mechanical processing. Taking smart watch cases as an example, on average, one tool is lost for every four cases produced, which is a huge cost.

4、 Grinding and polishing

Grinding and polishing are almost necessary steps in the processing of every material, with the aim of presenting products with more precise dimensions and finer textures. Often, small polishing particles or consumables are used to finely polish every position on the surface of the product. At the same time, special effects can also be achieved through specific process schemes, such as high gloss mirror surfaces, matte frosted surfaces, and so on.

5、 Wire drawing

The surface of titanium metal can be brushed to form a matte texture. This titanium metal wire drawing effect has a very high appearance rate in consumer electronics products, balancing delicate touch and visual aesthetics, and is recognized and favored by more consumers.

6、 Laser engraving

There are mainly laser drilling and welding processes.

7、 Sandblasting

The main purpose of sandblasting process on titanium alloy surface is still functional. Including improving the adhesion of titanium metal surface, extending the service life (removing surface impurities, etc.), and increasing the surface smoothness and aesthetics of the product. It can also be understood as the effect of serving other surface treatment processes.

Apple's previous new patent mentioned titanium alloy and sandblasting process. By combining a new sandblasting process with etching and anodizing, the surface effect of titanium alloy is treated. It can remove impurities and extract essence, achieving better protection and appearance. It is reported that Apple's latest iPhone 15 Pro uses sandblasting process for its titanium metal frame.

A good method for surface treatment of titanium metal products, especially in the field of precision electronic products, is to composite dissimilar metals before making the appearance. The pain point lies in the relatively high cost, as the composite of dissimilar metals must maintain their unique properties and characteristics, while also meeting the requirements for large-scale production, resulting in a higher price. The latest iPhone 15 Pro launched by Apple adopts a brand new structural design, wrapped in a new secondary structure made of 100% recycled aluminum metal. It uses new thermal mechanical processing and other processes to achieve high-strength bonding between these two metals through solid-state diffusion and ultra-high pressure. However, the actual effect is still unsatisfactory, and the surface treatment technology of titanium metal needs further improvement.