Wear Behavior of Fiber Laser Textured TiN Coatings in a Heavy Loaded Sliding Regime

Abstract

In heavy loaded mating components, such as sliders and sliding bearings, guaranteeing the efficiency of lubricant films for long times during severe service conditions is very complicated. In this work, the benefits deriving from the use of fiber laser sources for surface texturing of very thin TiN coatings in severe wear working conditions were demonstrated. Evaluations of the laser textured dimples shape, geometry and density are given. Wear performance of the fiber laser textured surfaces was evaluated in discontinuous oil lubricated conditions with a flat contact. High normal load and low sliding speed were applied. Comparison tests were also performed on commercial TiN and WC/C coatings. In terms of average wear volume and maximum wear depth, Laser Surface Texturing of TiN provided respectively a 70% and a 45% reduction if compared to plain TiN. If compared to WC/C the wear resistance gains were lower but LST TiN maintained such benefits for longer wear runs. SEM analysis also revealed that the laser interaction provided a localized thermal cracking to the TiN coating. However, the sliding action caused very limited and localized coating fragmentation or delamination.

An overview of geometrical parameters of surface texturing for piston/cylinder assembly and mechanical seals

“…In the case of full or mixed lubrication regime micro textures increase load carrying capacity by serving as micro hydrodynamic bearings [3,5,[26][27][28][29]. Micro surface texturing can produce hydrodynamic effect between parallel sliding bodies.…”

“…Surface textures can act as lubricant reservoirs or secondary lubricant source [27,28,[32][33][34]. During sliding of surfaces, this lubricant will be drawn up to permeate the surfaces and can reduce friction, wear and seizer.…”

“…Hydrodynamic pressure profile by an ideal micro asperity a without cavitation, b with cavitation Meccanica way textures can help in removing the unwanted wear debris from surface in dry as well as lubricated conditions[4,27,28,[33][34][35][36][37][38][39][40].…”

Evaluation of Self-Mixing Interferometry Performance in the Measurement of Ablation Depth

“…Particularly in percussion drilling, molten steel from the substrate is deposited at the entrance of the blind hole. For laser surface texturing in view of friction applications, where a great number of microholes are realized over large areas to make a reservoir of solid or liquid lubricant [3], substrate reach can cause coating failure [2]. Thus, online monitoring capabilities are required to overcome process variations during the machining of large area components.…”

Effect of Surface Texturing on Stresses during Rapid Changes in Temperature

“…It is the process of applying a specific type of pattern of roughness to a surface in order to change its properties. Some recent publications [1][2][3][4][5][6][7][8] have mentioned its many roles, such as in the elimination of interface friction and wear, in the enhancement of the lubrication state, for mechanical seals, etc. For example, Shen et al [9] studied the tribological and sealing performance of a piston ring with a specially-designed textured surface in a diesel engine and found that surface texturing led to a reduction of up to about 15% in total friction.…”