http://www.123seminarsonly.com/Seminar-Reports/2013-04/80827267-Coatings-tribology-contact.pdf

Coatings tribology—contact mechanisms and surface design

Triboelectrochemical techniques and interpretation methods in tribocorrosion: A comparative evaluation

Nanotribology and MEMS

Electrochemical techniques for studying tribocorrosion processes

Carbon-based thin films possess unique and adjustable combination of properties such as high hardness and wear resistance, chemical resistance and good tribological performances Among critical variables to tailor a-C film’s properties for specific application is the distribution of the carbon hybridization states (sp 1 , sp 2 and sp 3 bonds), the atomic H content, the content in dopants such as Si, F, N, B and O Here we focus on: (i) a-C and hydrogenated amorphous carbon (a-C:H) films with a mixture of sp 2 and sp 3 bonding, highly sp 3 -boned material (ta-C) and sp 2 -bonded carbon, (ii) carbon nitride (CN x ) coatings and (iii) metal/amorphous carbon (a-C:M) composite films The study is focused on the review of the nanomechanical properties and analysis of the nanoscratching processes at low loads to obtain quantitative analysis, the comparison of their elastic/plastic deformation response, and nanotribological behavior of the a-C, ta-C, a-C:H, CN x , and a-C:M films For ta-C and a-C:M films new data are presented and discussed

Nanomechanical and nanotribological properties of carbon-based thin films: A review

Corrosion-wear of passivating materials in sliding contacts based on a concept of active wear track area

Friction mechanisms at the micro-scale

The properties of thin hard coatings and consequently their functionality are influenced by microstructural characteristics such as phase composition and grain size distribution. Recent studies indicate that microlaminated hybrid coatings offer an opportunity to establish unique and controllable microstructural characteristics. A variety of interlayers has been used in hybrid coatings for various purposes: (1) to enhance the adherence between coatings and substrates, (2) to prevent crack initiation, (3) to give good shock resistance, (4) to tailor the thermal expansion characteristics, which leads to good interfacial strength, (5) to prevent diffusion of substrate species into coatings or vice versa during annealing, (6) to enhance corrosion protection of coating and substrate, and (7) to enhance sliding wear resistance or lower sliding friction. In order to obtain the above mentioned properties, various surface modification techniques such as (1) electrodeposition, (2) thermal treatment, (3) ion plating, (4) ion implantation, and (5) sputtering can be used to prepare hybrid coatings. This review includes a discussion on surface modification techniques and properties of different hybrid coatings.

Hybrid processes — a versatile technique to match process requirements and coating needs

R.f. plasma CVD deposited diamond-like carbon coatings (DLC) possess interesting wear properties in dry testing conditions or in vacuum applications. Extremely low friction coefficients are displayed in dry test conditions, the friction coefficient being dependent on relative humidity and presence of oxygen. The question arises whether these coatings are equally effective in an aqueous medium. Parameters controlling the through-coating porosity are discussed and their relative importance indicated. A coulometric quantitative porosity measurement has been used. Characterisation by light optical microscopy, profilometric measurements and EPMA suggest the importance of the microstructure of the substrate material. Further, pin-on-disk wear tests in water show a detrimental damage when compared to dry wear tests. De-adhesion of the coating occurs in an early stage with subsequently a rapid destruction of the coating. Important parameters in this failure mechanism are the initial contact stress and the development of this stress by initial wear.

Dirk Drees

Papers

Electrochemical techniques for studying tribocorrosion processes

Corrosion-wear of passivating materials in sliding contacts based on a concept of active wear track area

Friction mechanisms at the micro-scale

Hybrid processes — a versatile technique to match process requirements and coating needs

The electrochemical and wear behaviour of amorphous diamond-like carbon coatings and multilayered coatings in aqueous environments