Tribological behavior of select MAX phases against Al2O3 at elevated temperatures

✍ Scribed by S. Gupta; D. Filimonov; T. Palanisamy; M.W. Barsoum

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 711 KB
• Volume: 265
• Category: Article
• ISSN: 0043-1648
• DOI: 10.1016/j.wear.2007.11.018

✦ Synopsis

The layered M n+1 AC n ternary carbides -MAX phases -Ta 2 AlC, Ti 2 AlC, Cr 2 AlC and Ti 3 SiC 2 were tested under dry sliding conditions against alumina at 550 • C and 3 N load (for a stress of ≈0.08 MPa) using a pin-on-disk tribometer. Ta 2 AlC and Ti 2 AlC exhibited low specific wear rates, SWRs, (≤1 × 10 -6 mm 3 /N m), while the coefficients of friction, μ, were ∼0.9 and ∼0.6, respectively. At 0.4, μ of Ti 3 SiC 2 was the lowest measured, but the SWR, at ≈2 × 10 -4 mm 3 /N m, was high. With a μ of 0.44 and a SWR of 6 × 10 -5 mm 3 /N m the Cr 2 AlC sample was in between. No visible wear of Al 2 O 3 counterparts was observed in all the tribocouples. Tribofilms, which were mainly comprised of X-ray amorphous oxides of the M and A elements and, in some cases, unoxidized grains of the corresponding MAX phases, were formed on the contact surfaces. The correlations between observed tribological properties and tribofilm characteristics are discussed.