DLC coatings are much known for their wear resistance and are very hard. These coatings find various applications in biomedical and mechanical applications where wear resistance is required.

1. DLC COATING FOR
TRIBOLOGICAL APPLICATION
Presented By
Koushik Kosanam 1RV15ME052
Deepak Udupa 1RV15ME051
R.V. College of Engineering
Department of Mechanical Engineering
Technical seminar on

2. INTRODUCTION
DLC COATING
• A DLC film can be defined as an amorphous film consisting of an
irregular mixture of diamond atoms that form sp3 bonds (diamond
structure) and diamond atoms that form sp2 bonds (Graphite structure)
• Unique mechanical, chemical, optical, and electrical properties.
• Quite hard, strong, and stiff.
• Most DLC films are electronically insulating and can be made optically
transparent to visible and ultraviolet light.
• DLC films are chemically inert and impervious to acidic and saline
media.
• They are amorphous.

3. INTRODUCTION
• DLC films may also have large amounts of hydrogen in their amorphous
structures.
• Hydrogen-free DLC films can also be deposited.
• Doping DLC films with dopant such as Cr, F, Ag to achieve better
electrical and mechanical properties is also possible.
Diamond
structure
Graphite structure DLC Coating structure

4. INTRODUCTION
TRIBOLOGY PROPERTY
• The mechanical and tribological properties depend on microstructures,
chemistry, hydrogen content, sp2/sp3 bonded carbon.
• Friction coefficients of the DLC films: 0.01 to 0.5
• Relative humidity has the greatest effect on the friction of DLC films.
• Hydrogen-free DLC films: best in humid air
• Hydrogenated DLC films: best in dry or inert conditions.
• At high temperatures, most undoped DLC films undergo permanent
chemical and microstructural changes that degrade their friction and
wear behavior (e.g., graphitization).

5. INTRODUCTION
MANUFACTURING PROCESS
• Process: Plasma Enhanced Chemical Vapor Deposition (PE-CVD) at room
temperature. Other methods are magnetron sputtering method, ion beam
process etc
• Source gas for manufacture
• Pure methane
• Mixture of methane and increasing hydrogen
• Generally film thickness used is1 μm
• DLC films deposition range: subzero to 400oC.
• Processes: plasma or ion beam- PVD and CVD.
• Carbon source: hydrocarbon gas like CH4, C2H2.

6. LITERATURE REVIEW
• [1] A Comparative study of microstructural and tribological properties of
N-DLC/DLC double layer and single layer coatings deposited by
DCpulsed PACVD process, Omid Sharifahmadian et al, accepted
manuscript
• The double layer (N-DLC/DLC) coating and the single layer (DLC and N-DLC)
coatings were deposited by D.C. Pulsed PACVD technique
• The small amount of nitrogen in the second layer of the N-DLC/ DLC coating
causes a slight reduction in the total sp3 carbon bonds and the hardness of
the coating which improves coating adhesion to the surface
• With the deposition of the NDLC/DLC coating, optimum mechanical and
tribological properties, as well as proper adhesion between the coating and the
substrate, are achieved.

7. LITERATURE REVIEW
• [2] Evaluation of Anti-Corrosion Properties of DLC Coatings for Medical
Devices , Eraj Humayun Mirza et al, (ICoBE),27-28 February
2012,Penang
• The DLC coatings with Fluorine content were prepared by rf-PECVD technique
while Si-doped DLC coatings were prepared by magnetron sputtering method,
on the stainless steel substrates
• F-DLC showed the better corrosion resistant properties
• F- DLC has low surface energy than Si-DLC which limits the growth of bacteria
• Si-DLC could be used for high temperature applications with considerable
corrosion resistant properties

8. APPLICATIONS
• Medical devices and implants: Anti bacterial properties
• Glass: anti-scratch
• Moulds: to produce smooth surface and reduce wear
• Engine and space parts: low friction
• Cutting tools: Wear resistance and to increase lifetime
• Oil & gas pipelines: super lubricity in pipes

9. APPLICATIONS
• [3]‘Silver doped nano composite cabon coating for bio medical
applications’ ,D.Bociaga et al, Applied Surface, Science ,2015 , pg 388–
397
• Formation of bio film on the biomedical devices is a major concern.the silver
doped dlc coating (Ag-DLC) limits the growth of bacterias and has no effect on
human cells
• [4]‘Water-lubricated behaviour of AISI 440C stainless steel and a DLC
coating for an orbital hydraulic motor application’, E. Strmčnik et al,
accepted manuscript
• The coefficient of friction for SS/DLC contacts in water was lower than the
coefficient of friction for SS/DLC in oil and lower than SS/SS in oil, a contact
that is in common use today

10. APPLICATIONS
• [5]Investigation of Cr(N)/DLC multilayer coatings elaborated by PVD for
high wear resistance and low friction applications, F.-D. Duminica et al,
Surface & Coatings Technology 337 (2018) 396–403
• Multilayer of Cr, Cr-DLC and DLC coating has shown best wear resistant
property with minimum friction. The coatig ca be applied to devices such as
ball bearings, engine parts like piston and piston pins etc
• F-DLC coating is used on Ti based medical implants due to its resistant
to bacterial activities

11. SUMMARY
• DLC films grown with pure CH4 exhibit relatively poor friction and wear
performance.
• DLC films grown with CH4 + increasing H2 exhibit increasingly better friction and
wear performance.
• Different dopant to the film shows different properties to suit its application
LIMITATIONS
• DLC film is not a specific material, but a group of amorphous carbon materials.
The coating should be carefully monitored and optimized from the atomic level
• DLC coated medical implants have a lifetime of around 10 years

12. REFERENCES
1. A Comparative study of microstructural and tribological properties of N-
DLC/DLC double layer and single layer coatings deposited by DCpulsed
PACVD process, Omid Sharifahmadian et al, accepted manuscript
2. Evaluation of Anti-Corrosion Properties of DLC Coatings for Medical
Devices , Eraj Humayun Mirza et al, (ICoBE),27-28 February 2012,Penang
3. ‘Silver doped nano composite cabon coating for bio medical applications’
,D.Bociaga et al, Applied Surface, Science ,2015 , pg 388–397
4. ‘Water-lubricated behaviour of AISI 440C stainless steel and a DLC coating
for an orbital hydraulic motor application’, E. Strmčnik et al, accepted
manuscript
5. Investigation of Cr(N)/DLC multilayer coatings elaborated by PVD for high
wear resistance and low friction applications, F.-D. Duminica et al, Surface
& Coatings Technology 337 (2018) 396–403

13. THANK YOU