Ni3Al Matrix Composite with Lubricious Tungstate at High Temperatures

Abstract

Ni 3 Al-Ag-BaF 2 /CaF 2 -W composites were fabricated by the powder metallurgy route, and their tribological properties over a wide temperature range, starting from room temperature up to 800°C, were investigated. The Ni 3 Al matrix composite with 15 wt% BaF 2 /CaF 2 exhibited a favorable friction coefficient (range 0.3-0.4) and wear rate (0.2-6.2 9 10 -4 mm 3 N -1 m -1 ). The formation of BaWO 4 and CaWO 4 with lubricity on the worn surface due to a tribo-chemical reaction at high temperatures provided excellent lubricating properties. The low friction coefficient over a broad temperature range could be attributed to the synergistic effect of Ag,

High Temperature Self-Lubricating Materials

“…As expected, barium and calcium tungstates with lubricious properties contributed to low friction coefficient at elevated temperatures [50].…”

“…Recently, a series of Ni3Al high temperature self-lubricating composites were developed in Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences [15,[48][49][50][51][52][53][54][55]. The selflubricating composites, which consist of Ni3Al matrix with Cr/Mo/W, Ag and BaF2/CaF2 additions, exhibit the low friction coefficient and wear rate at a wide temperature range from room temperature to 1000 °C.…”

Re‐attainable lubrication films at 500°C converted through the positional polymerisation of DCDPS on the preset Na2S coating

“…Traditional lubricating oils and greases could not withstand temperatures exceeding 300 C. Therefore, lubrication at this temperature is normally focused on metal matrix, 1,2 intermetallic matrix 3,4 and ceramic matrix 5 lubrication coatings. However, these solid lubrication coatings need to be pre-coated to the friction surface before friction can commence.…”

Analytical model and experimental validation of the local damage mechanism of solid lubricant films for metal matrix self-lubricating composites

“…Shi et al 8,9 reported the friction and wear performances of TiAl matrix self-lubricating composites reinforced by different solid lubricants at high temperatures and also observed that the solid lubricant lms formed on the worn surfaces improved the friction and wear performances of the composites. Zhu et al 10,11 explored the tribological performances of Ni 3 Al matrix self-lubricating composites reinforced by Ag and BaF 2 /CaF 2 at elevated temperatures and noticed that the tribological performances were enhanced over pure Ni 3 Al alloy, which was attributed to the formation of solid lubricant lms on the worn surfaces. Xu et al 12 investigated the tribological properties of TiAl matrix self-lubricating composites reinforced by WS 2 and ZnO and found that solid lubricant lms were formed on the worn surfaces, which were benecial for the improvement of tribological properties of the composites.…”

“…Zhu et al [10,11] explored the elevated temperature tribological performances of Ni 3 Al matrix self-lubricating composites reinforced by Ag and BaF 2 /CaF 2 and noticed that the tribological performances were enhanced over pure Ni 3 Al alloy, which was attributed to the formation of solid lubricant films on the worn surfaces. Xu et al [12] investigated the tribological properties of TiAl matrix self-lubricating composites reinforced by WS 2 and ZnO and found that the solid lubricant films formed on the worn surfaces, which were benefited to the improvement of tribological properties of composites.…”