This is not a reason for the question. This is a reason for literary search or even a little research. A scientist should be curious and adventurous.

Dear Dr. Nazir Monteiro dos Santos,

the use of carbon films inside titanium alloy pipe can be used, for example in the aerospace field, as protective coating increasing the lifetime of the tubes used in propulsion and thermal control systems of satellites. They can also inhibit the permeation of corrosive species (e.g. originated from the fuels and the cooling fluids) between the film-metal interface. In general, this method is a way to protect the Ti substrate against degradation.

Source: following, very interesting paper

"Carbon films deposition as protective coating of titanium alloy tube using PIII&D system"

N.M. Santos, S.F.M. Mariano, M.Ueda

Surface and Coatings Technology - Available online 6 July 2019

Best regards, Pierluigi Traverso

dear Nazir Monteiro dos Santos ;

the carbon-based coating & DLC usually used for enhancement of Titanium and its alloys performance in biomedical applications. DLC coatings are excellent in both bio- and hemocompatibility. in addition to its ability to increase the corrosion resistance, it increases hardness, toughness, and wear resistance.

for more details can read the following reference;

• Chapter Advanced Surface Treatments on Titanium and Titanium Alloys ...

Hybridyzing carbon nanotube with photocatalyst materials, such as titanium oxide and titanium silicate, improves their photocatalytic performance [1,2]. See also [3].

[1] M Krissanasaeranee et al., Chem. Phys. Lett. 496, 133 (2010).

Article Complex carbon nanotube-inorganic hybrid materials as next-g...

[2] Z Ren et al., Chem. Sci. 3, 209 (2012).

Article Hybridizing photoactive zeolites with graphene: A powerful s...

[3] K Tanaka, and S Iijima, Carbon Nanotubes and Graphene, 2nd edition (Elsevier, Amsterdam, 2014).

This is not a reason for the question. This is a reason for literary search or even a little research. A scientist should be curious and adventurous.

Please find this link. In this, paper talks about the Carbon films deposition as protective coating of titanium alloy tube using PIII&D system. You might get some useful information from this paper https://www.sciencedirect.com/science/article/abs/pii/S025789721930550X

Good Luck..