Surface Treatment Technology Of Titanium And Titanium Alloys To Prevent Adhesion

Titanium alloys are widely used in aerospace, military industry, civil industry and other fields due to their excellent specific strength, corrosion resistance, good high temperature performance and biocompatibility. However, titanium alloys have relatively low surface hardness and insufficient wear resistance, limiting their application in some specific environments. To improve these properties, researchers have developed a variety of surface treatment techniques to enhance the surface properties of titanium alloys.
1. Surface Oxidation
Enhances the lubricity of the surface of titanium alloys by forming an oxidized film, which reduces the adhesion phenomenon during the drawing process.
2. Coating
- Graphite Emulsion Coating
Graphite emulsion is applied prior to hot drawing to provide lubrication as well as to protect the billet surface from oxidation. Requirements for graphite emulsion include graphite content of 20-25%, particle size of 1-3um, and uniform adherence to the billet surface.
- Salt and Lime Coating
A salt-lime lubricating layer of specific formulation such as 12% Na2SO4, 12% CaO, 0.3% Na3PO4, 0.2% NaCl and residual water is used, supplemented by a mixture of 75% soap powder and 25% sulfur powder as a solid powdered lubricant.

- Fluorophosphate treatment
After cleaning the surface of the metal billet by physical methods, the solution is dipped to form a modified covering film on the surface, and then a solid lubricant is applied to obtain a low coefficient of friction and high wear resistance lubrication.
3. Plated metal film
A metal film such as copper, chromium, nickel or tin is plated on the surface of titanium alloy to reduce the direct metal contact during the drawing process and thus reduce the adhesion.
4. Boronizing
Titanium alloy wire into a mixed solution containing KFB4, BaCl2, NH4NO3 heated to boiling and then immersed, removed and washed and dried to generate a layer of fluoroborate on the surface of the wire. A layer of aluminum disulfide is also applied to the wire surface as a lubricant during cold piering.
5. Chemical conversion treatment
Through the chemical conversion treatment in the titanium alloy surface to form a dense chemical conversion film, this film can be used as a lubricant coating, adsorption of lubricants, so that the wire after a number of drawing the surface is smooth, no adhesion and skid marks.
6. Lubricant Selection
Selection of suitable lubricants, such as industrial soap powder, graphite milk and mixtures of soap powder and other materials, should have good wettability with the coating, better thermal stability.
7. Laser surface treatment
Laser treatment technology, including laser cladding, laser surface alloying and laser surface hardening, can be used to improve wear resistance, corrosion resistance and hardness by changing the microstructure of the surface layer. The advantage of laser treatment is that it can realize significant improvement of surface properties without changing the properties of titanium alloy matrix.
8. Micro-arc oxidation
This is a technology of in-situ growth of ceramic film on the surface of titanium alloy, which can form a layer of ceramic film on the surface of titanium alloy with excellent corrosion and wear resistance. The micro-arc oxidation technology is green and environmentally friendly, which is in line with the sustainable development strategy.
9. Ion implantation
By injecting nitrogen, oxygen, carbon and other elements into the surface of titanium alloy, the hardness and wear resistance of the surface can be improved. The thickness of the ion injection layer is usually in the nanometer scale, which can significantly improve the surface properties of titanium alloy.
10. Thermal Diffusion
By diffusing alloying elements into the surface of titanium alloy at high temperature, an alloying layer is formed, which improves the hardness and wear resistance of the surface.