Characterization of Diamond-like Carbon Coatings for Industrial Applications
Open Access
- Author:
- Newby, Sarah Katherine
- Area of Honors:
- Materials Science and Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Dr. Douglas Edward Wolfe, Thesis Supervisor
Dr. Robert Allen Kimel, Thesis Honors Advisor - Keywords:
- diamond-like carbon
tribology
Cathodic arc
PECVD
HiPIMS
Magnetron sputtering
DLC
friction
coating - Abstract:
- Amorphous diamond-like carbon (DLC) coatings can provide significant cost savings to industry as they offer improved tribological properties as well as reduced erosion and corrosion, especially in extreme environments. The performance of DLC coatings is a function of the deposited DLC’s intrinsic material properties which is determined by the coating deposition technique and processing parameters. There are several coating processes available for depositing DLC-based coatings, each with advantages and disadvantages. In order to identify which of the available processes produce coatings that maximize mechanical durability and wear resistance, DLC coatings from four deposition processes were investigated. DLC coatings deposited by cathodic arc deposition, magnetron sputtering deposition, high power impulse magnetron sputtering (HiPIMS) and plasma-enhanced chemical vapor deposition (PECVD) techniques on Ti-6Al-4V, 17-4 PH stainless steel, and silicon (111) substrates were characterized in order to establish processing-structure-property-performance relationships. Characterization techniques included scanning electron microscopy (SEM) to evaluate surface morphology and coating thickness, nanoindentation to determine hardness and modulus, Raman spectroscopy to probe carbon to carbon bonding, X-Ray diffraction (XRD) to investigate bond layer phase, laser interferometry and stylus profilometry to determine residual stress, and ball-on-disc tribology tests to assess wear resistance. The DLCs produced by cathodic arc deposition were determined to have the highest sp3 C-C bonding and largest intrinsic compressive stress (2 GPa). The DLCs deposited by PECVD and HiPIMS exhibited superior wear resistance and low friction (µ=0.18) at the conditions tested. The magnetron sputtered DLC was found to have poor tribological performance, and characterization confirmed a comparatively softer coating with an absent bond layer, intercolumnar microstructure and negligible residual stress (0.08 GPa).