Effect of ZnDTP triboflim's morphology on friction behaviors of DLC coatings: Tribofilm characterization by 3D scanning electron microscope observation

Abstract

ZnDTP antiwear additive for lubricating oil is known to absorb strongly on sliding surfaces in boundary lubricated tribosystems, forming a tribofilm, which is able to reduce the wear of involved surfaces. It is also known to increase the friction coefficient in most DLC/DLC contacts, with the exception of ta-C DLC / ta-C DLC contact, for which the difference in friction behaviors between a base oil + ZnDTP additive lubricated tribosystem and a base oil lubricated tribosystem is not very significant. In this study we investigate a characterization method of the shape of the tribofilm formed on different types of DLC coatings and on the relation between the shape of the tribofilm and the friction behavior of the related DLC coating. Results show that compared to other investigated DLC types, the tribofilm formed on ta-C DLC has some unique characteristic topography features that promote lower friction coefficient.

The Tribological Property of a-C:H Coating with Tribolayer by Additive Having Glycerol and Phosphate Oxide Structure

“…Using a metal morphing surface to control lubricant thickness between mating surfaces so that friction force is reduced [1,2], and using a carbonaceous hard coating (for example, tetrahedral amorphous carbon (ta-C) [3][4][5][6], hydrogenated amorphous carbon (a-C:H) [7][8][9], amorphous carbon (a-C), or other dopant types [10,11]) are methods for overcoming this situation. However, some additives cause high coating wear [12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Influence of defects in sp2-bonded network of diamond-like carbon on silica scale adhesion in geothermal power plants

“…Murashima et al revealed that nitrogen-containing ta-C coatings have lower surface energy, resulting in few adhesion between ceramic particles and the ta-C coatings [25]. The coatings are known to develop unique tribolayer derived from oil additives, providing low friction and low wear tribo lms [26][27][28][29]. The a-C:H coatings are generally deposited by chemical vapor deposition (CVD) method, showing lower hardness, carbon diffusion during friction, and less chemical stability due to its sp2-rich carbon structure [27][28][29][30].…”

“…The coatings are known to develop unique tribolayer derived from oil additives, providing low friction and low wear tribo lms [26][27][28][29]. The a-C:H coatings are generally deposited by chemical vapor deposition (CVD) method, showing lower hardness, carbon diffusion during friction, and less chemical stability due to its sp2-rich carbon structure [27][28][29][30]. The carbonaceous structure is considered to easy to react with additive molecules on the surface, developing thick tribo lm or bring severe chemical wear of the coating [31][32][33][34][35][36][37].…”

Interplay of mechanics and chemistry governs wear of diamond-like carbon coatings interacting with ZDDP-additivated lubricants

“…The thicknesses and morphologies of these tribofilms are affected by intrinsic parameters of the DLC coatings, i.e. hydrogen content, sp 2 / sp 3 ratio, presence of dopants, surface roughness and mechanical properties 6 , 20 . The former three factors alter chemical reactivity of DLC surfaces and thus reaction rates of ZDDP, whereas the latter two factors affect the mechanical response of the system such as contact pressure and geometry, and elastic/plastic deformation of surface asperities.…”