Enhancement of Dry Sliding Tribological Characteristics of Perforated Zirconia Toughened Alumina Ceramic Composite Filled With Nano MoS2 in High Vacuum

Abstract

Abstract An innovative approach was adopted for fabricating zirconia toughened alumina (ZTA)-MoS2 self-lubricating ceramic composites with the inclusion of hydrothermally synthesized nano MoS2 through the micropores of perforated ZTA ceramics. This method avoided the exposure of MoS2 in high-temperature environment due to its in-sensitiveness during traditional sintering techniques. Different weight percentages (wt%: 0, 5, 10, and 15) of graphite were incorporated to produce porous ZTA ceramics with the help of cold press sintering followed by insertion of nano MoS2 into the matrices. Best tribological characteristics were obtained with 10 wt% graphite-ZTA-MoS2 specimen which offered an improvement of ∼66% in coefficient of friction (COF) and ∼96% in specific wear rate when dry sliding tests were carried out against silicon nitride (Si3N4) in high vacuum (5.0 × 10−4 mbar). Nano MoS2 was sheared off at the contacting interface during sliding under load which showed a good tribological characteristics of the composite. Delamination was found as the dominating wear mechanism in ZTA-MoS2 composites during wear tests.