Surface texturing for adaptive Ag/MoS2 solid lubricant plating

Synergetic effects of surface texturing and solid lubricants to tailor friction and wear – A review

“…Silver has been applied as a solid lubricant to textured hard surfaces either on its own [161,162] or in combination with MoS2 [163,164]. Other metals that have been used as solid lubricants on textured surfaces are copper (Cu) [165], indium (In) [166,167], magnesium (Mg) [168], or multiple metals combined in Sn-Ag-Cu [169][170][171].…”

“…Metallic solid lubricants have been deposited onto various hard materials and coatings with surface textures, including steel [164,169,174,175], WC [165], VN [172], Ni3Al [170], TiN [166,167], TiAlCN [163], Ni [161] and Ta [162]. Textures in the form of dimples/pores [162-164, 166, 167, 169, 172, 173] or grooves [170] have been studied.…”

“…The solid lubricants were used to fill the textures with lubricious material. Textures have been filled with metallic materials using various techniques, including sputtering [162,163,166,167], electrodeposition/electroless plating [161,164], hand burnishing [172,173], spraying followed by grinding and polishing [165], or additive manufacturing of the material in powder form [169,170].…”

“…As discussed later, many of these studies have been performed at high temperatures to best leverage the lubricious nature of metals when they soften. Several studies have also explored the effect of texture size and distribution on the surface and shown that performance improves and then deteriorates with increasing dimple or groove density [161,162,164,167,170]. This observation is attributable to the fact that higher texture densities provide more lubricating material, but there is a limit to this benefit as the surface approaches a flat surface from which the solid lubricant is easily removed during sliding.…”

“…Studies often report improved friction or wear achieved through the combination of textures and metallic solid lubricants. The most commonly cited mechanism to explain this synergy is that the textures act as lubricant reservoirs that release lubricious material to the sliding contact or to the counter-body gradually during sliding [161,163,164,166,167,169]. An illustration of dimples acting as reservoirs for silver is shown in Figure 7.…”