What are the surface treatment processes for titanium metal?
1. Anodizing
Anodizing is a well-known and mature process, so I won't introduce it too much here. In addition to the commonly used aluminum alloy anodes, titanium metal can also be used as anodes, and most titanium coloring processes are achieved through anodization, which can produce richer colors and patterns with a high degree of differentiation, including ice crystal flowers, threads, etc. Various. other options.
In addition to decoration, the anodizing process also forms a dense film layer on the metal surface of the product to enhance mechanical properties, wear and weather resistance, insulation, and improve the bonding force with the coating.
It's worth mentioning here that titanium alloys are different from aluminum alloys. Although the cost of titanium as an anode is higher, the hardness of the oxide film formed by titanium alloy is worse than itself. Therefore, generally speaking, many manufacturers will choose to make anodes on the surface of pure titanium products. For example, several products in the picture have an anode effect on the surface of GR5 pure titanium material.
Most titanium products are colored using an anodizing process, but then require some surface treatment for protection. For example, iPhone 15 Pro, in addition to the original color titanium silver, the other three colors (black, white, and blue) are all colored using anodizing technology. This is followed by PVD for functional protection.
2.PVD coating
PVD is physical vapor deposition, a type of vacuum coating, and the process is very mature. PVD treatment can be performed on titanium alloy surfaces. The main purpose is to add a functional coating that protects and protects the surface. However, it is worth noting that currently PVD as a functional material can only barely pass the test, and the durability needs to be improved unless the performance of the PVD primer material is very good.
Take the iPhone 15 Pro as an example. Among the four colors of black titanium, white titanium, blue titanium and natural titanium, except for the primary color titanium silver, the other three colors are based on anodes and equipped with PVD coating process to increase the surface performance of the product. However, problems such as subsequent fading still occur, which also reflects the shortcomings of PVD in terms of durability.
Of course, in addition to functionality, coloring effects can also be achieved. Overall, the design quality of the product can be greatly improved.
3. CNC
Titanium alloy CNC machining mainly plays the role of shaping and finishing. One of the bigger problems during machining is tool loss. Because titanium alloys are harder, they are more difficult to machine than other metals. During the cutting process, the tool is subjected to high temperature, large cutting force, long friction distance, large vibration deformation, tool sticking, etc., resulting in serious tool wear. Titanium alloys are difficult to machine with conventional tools. Special composite-coated knives, or even diamond knives, must be used to machine them well with CBN knives. Take smartwatch cases as an example. On average, one tool is lost for every four watch cases produced, which is a huge cost.
4. Grinding and polishing
Grinding and polishing are necessary steps in the processing of almost all materials. The purpose is to allow the product to present a more precise size and a more delicate texture. It is often necessary to use fine polishing particles or consumables to finely polish every position on the product surface. At the same time, special effects can also be achieved through specific process solutions, such as high-gloss mirror, matte frosting, etc.
5. Drawing
The titanium surface can be brushed to create a matte texture. This titanium brushed effect appears very frequently in products in the consumer electronics industry. Taking into account the delicate touch and visual beauty, it is recognized and favored by more consumers.
6. Laser engraving
It mainly includes processes such as laser drilling and welding.
7. Sand blasting
The main purpose of the sandblasting process on titanium alloy surfaces remains functionality. Including improving the surface adhesion of titanium metal, extending the service life (removing surface impurities, etc.) and increasing the smoothness and aesthetics of the product surface. It can also be understood as serving the effects of other surface treatment processes.
A new Apple patent previously mentioned titanium alloy and sandblasting process. The surface effect of titanium alloy is achieved through a new sandblasting process that combines etching and anodizing. It removes roughness and extracts essence for better protection and appearance. It is understood that Apple's latest iPhone 15 Pro titanium frame uses a sandblasting process.
In the surface treatment of titanium metal products, especially in the field of precision electronic products, a better method is to combine dissimilar metals to create the appearance. The pain point is that the cost is relatively high. The reason is that dissimilar metal composite materials must maintain their own special properties and characteristics while meeting mass production, so they are relatively expensive. Apple's latest iPhone 15 Master features a new structural design, wrapped in a new secondary structure made of 100% recycled aluminum metal, using new thermo-mechanical processing and other processes. The ultra-high pressure of solid-state diffusion enables a high-strength bond between the two metals. However, the actual effect is still not satisfactory, and the surface treatment technology of titanium metal needs to be further improved.
