Increasing the coefficient of sliding friction of NiCr at low loads by interstitial surface hardening

Abstract

NiCr alloys are of technical interest for vibrational damping structures operating at hightemperature (> 1000 C) [1]. For this purpose, woven wire meshes have been developed that consist of NiCr alloy (Ni-20Cr) wires. The inter-wire forces in these structures are estimated to be about 0.05 N [2]. Increasing the coefficient of sliding friction (COF) between the wires at these loads would improve the damping behavior. It has been reported that hardening metal alloys without changing the composition decreases COF. For example, implanting martensitic steel with carbon or nitrogen increases hardness by about two times and reduces the COF (in air) by a factor of 8 [3]. Work hardening of an aluminum alloy doubles the hardness and decreases the COF from 1.4 to 0.9 [4]. Annealing a CuZrAl bulk metallic glass raises the hardness from 480 HV to 530 HV and reduces the COF from 0.5 to 0.4 [5].

Development of Silane-Based Coatings with Zirconia Nanoparticles Combining Wetting, Tribological, and Aesthetical Properties

“…The higher percentage of ZrO2 promotes the lower friction coefficient, possibly related not only to ZrO2 amount but to presence of agglomerates (as XRF and SEM have shown), being able to stand wear. A similar conclusion was drawn by Banerjee et al [11] for fluorosilane coatings with colloidal silica nanoparticles, showing that increasing the concentration of added silica to the sol-gel matrix led to a harder and more wearresistant coating on the surface [45].…”