Titanium Bar Surface Treatment: Corrosion & Wear Resistance

Titanium bars  are widely used in structural components, transmission parts, implant devices and other fields. However, their low surface hardness and poor wear resistance, along with the susceptibility to pitting and crevice corrosion in harsh environments. Surface treatment can enhance their corrosion and wear resistance, enabling performance customization.

 

 

 

1.1 Mechanical Treatment

It modifies the surface of titanium bars through physical effects, featuring no chemical reagents, simple processes and low costs.

Mechanical polishing can achieve a mirror finish with a surface roughness Ra ＜ 0.01 μm through step-by-step grinding.

Sandblasting removes oxide layers and contaminants via the impact of high-speed sand particles, forming a rough surface with Ra 2–5 μm to improve bonding strength.

 

1.2 Chemical Treatment

It regulates the surface state, removes impurities and optimizes flatness through the reaction between chemical reagents and the titanium bar surface, laying a foundation for subsequent strengthening.

Chemical polishing uses weak acid or alkaline solutions to improve surface finish and requires silane sealing.

Pickling purification adopts a hydrofluoric acid-nitric acid mixed solution to remove oxide scales and impurities.

Atmospheric oxidation can thicken the oxide film at high temperatures to improve corrosion resistance.

 

 

2.1 Electrochemical Treatment

It forms a dense oxide film on the titanium bar surface through electrolysis, which has both corrosion and wear resistance with controllable processes.

Anodization applies a voltage of 10–200 V in a sulfuric acid electrolyte to prepare a TiO₂ film with a thickness of 1–30 μm, which enhances wear resistance, corrosion resistance and biocompatibility; adjusting process parameters can prepare porous TiO₂ nanotube arrays for photocatalysis and sensor fields.

Micro-arc oxidation, an upgraded anodization technology, applies a high voltage of 300–600 V to form a ceramic-grade oxide layer with a hardness of HV 1500+ and high temperature resistance above 800 ℃, as well as good insulation performance.

 

2.2 Heat Treatment Modification

It forms a hard alloy layer on the titanium bar surface through high-temperature or plasma element diffusion, improving hardness, wear resistance and corrosion resistance.

Nitriding is the most widely used technology, which can form a TiN/Ti₂N layer with a thickness of 5–20 μm and a hardness of HV 2000, reducing the friction coefficient by 60%, and is mostly used for high-load transmission parts; plasma nitrooxidation forms a composite layer with better performance and small deformation.

Carburizing forms a TiC layer with a thickness of 2–10 μm and high temperature resistance up to 800 ℃; boriding has high hardness but complex processes.

 

2.3 Coating and Composite Technologies

It can prepare functional coatings on the titanium bar surface to customize corrosion and wear resistance, which is an important means for surface strengthening of titanium bars.

Lubricating and anti-adhesive coatings are used to reduce friction: graphite emulsion coatings form a 1–5 μm lubricating film, which resists oxidation and reduces processing loss by more than 30%; fluorophosphate coatings have a friction coefficient as low as 0.1.

High-end functional coatings: bioceramic (HA) coatings are used for orthopedic implants to promote osseointegration; DLC coatings have a hardness of HV 3000–5000 and a friction coefficient of 0.05; precious metal coatings have good corrosion resistance but are prone to spalling and high in cost; electroplated nano-nickel and silver can improve wear resistance and anti-seizure performance, solving the "seizure" problem of aerospace blades.

 

 

3.1 Laser Surface Treatment

It modifies the titanium bar surface with high-energy laser, featuring high speed, high precision and little impact on the matrix, and can simultaneously enhance wear and corrosion resistance.

Laser cladding uses Gr5 titanium powder to prepare a 0.5–2 mm alloy layer, improving wear resistance by 5 times, suitable for heavy-duty working conditions.

Laser surface alloying can infiltrate nitrogen and carbon to form a gradient layer with HV 1000–2000.

Laser colored titanium processing combined with anodization takes into account protection and decoration.

 

3.2 Ion Implantation Technology

It injects nitrogen, oxygen, carbon and other ions into the titanium bar surface with a depth of 0.1–1 μm, which can increase the hardness by 3 times and reduce the corrosion current density by two orders of magnitude. This technology does not change the matrix performance and achieves nanoscale strengthening.

Implanting precious metal ions can achieve better corrosion resistance, but it is high in cost and still under research.

 

3.3 Composite Modification Technology

Single surface treatment is difficult to meet complex working conditions, and the combination of multiple technologies has become the mainstream. The combination of anodization and magnetron sputtering can prepare TiO₂/Ag antibacterial coatings with an antibacterial rate of ＞99%, suitable for medical devices and implants; the combination of plasma nitrooxidation and laser cladding takes into account corrosion resistance and heavy-duty wear resistance.

 

 

Specialized in manufacturing titanium round bars, we welcome your inquiries at: Sam.Rui@bjrh-titanium.com