Tribological Characteristics of AlMgB14 and Nanocomposite AlMgB14-TiB2 Superhard Coatings

This study investigated the friction and wear characteristics of two super-hard coatings on M2 steel. One was AlMgB(14), produced by pulsed laser deposition (PLD), and the other was a nanocomposite of AlMgB(14)-TiB(2), produced by physical vapor deposition (PVD). Tests were conducted tinder unidirectional and reciprocating sliding against AISI 52100 bearing steel in both dry and oil-lubricated conditions. The AlMgB14 coating exhibited an encouraging but short-lived low friction stage (mu = 0.2) in dry sliding. The AlMgB(14)-TiB(2) coating reduced the wear rates by one order of magnitude relative to the M2 steel and three orders of magnitude for the counter-face in dry sliding. This nanocomposite coating also demonstrated significant extension (>2.5X) of the low friction (non-scuffing) stage when sliding under starved lubrication.