Diamond-like carbon thin films deposited by pulsed-dc plasma on a martensitic steel
- Authors
- Pantoja Su?rez, Luis Fernando
- Format
- Article
- Status
- publishedVersion
- Description
In this work, diamond-like carbon (DLC) films with thicknesses up to 3.2 ?m, were deposited on martensitic steel substrates on a buffer layer of Ti. The objective is to improve their surface properties through the application of a pulsed-dc plasma technology and optimizing ion treatment to increase the roughness of the steel surface and the use of a buffer layer prior to the growth of DLC layer. First, the substrate surface was prepared by a sputter-cleaning process using argon plasma. The morphological and nanostructural properties of the substrate surface were studied by scanning electron microscopy (SEM) equipped with an energy dispersive X-ray (EDX) detector and atomic force microscopy (AFM). Both the EDX spectrum and the AFM images revealed a substrate surface with nanometric roughness. Afterwards, the titanium thin film, which acts as a buffer layer, was grown by a magnetron sputter deposition. DLC was subsequently deposited by plasma enhanced chemical vapour deposition (PECVD) method, using a pulsed-dc power supply and pure methane (CH4) as reactant gas. Both processes were performed without breaking the vacuum. Several experiments were carried out to identify the influence of the technological parameters (methane flux, pressure, power and pulse frequency) on both the morphological and the mechanical properties of DLC/Ti films. The mechanical properties and wear resistance of the DLC films were determined by Nanoindentation technique, using a continuous system measurement (CSM) module, and grinding calottes with a defined geometry, respectively. The results showed hardness values around 16 GPa for the best DLC film. The improvement of the technological parameters of pulsed-dc power technique and Ti buffer layer has reduced the residual stress to the range of 0.13 GPa 0.64 GPa. The residual stress of the DLC films, deposited by other techniques such as RF PECVD, presents values as high as 2 GPa. In addition, low wear rates of 10 4 10 8 mm3 N 1m 1 have been achieved.
- Publication Year
- 2014
- Language
- eng
- Topic
- DIAMOND-LIKE CARBON
MAGNETRON SPUTTERING
TI BUFFER LAYER
TRIBOLOGICAL BEHAVIOUR
- Repository
- Repositorio SENESCYT
- Rights
- openAccess
- License
- restrictedAccess