Friction and wear behaviour of in-situ transformed Cf/Al2O3 composite under different lubrication conditions

Abstract In this paper,the friction, wear behaviour, and wear mechanisms of in-situ transformed carbon fibre toughened alumina ceramic matrix composite were investigated. The 20 vol% C f /Al 2 O 3 composites were fabricated by hot-press sintering in vacuum. Wear tests for 20 vol% C f /Al 2 O 3 composite, commercial Al 2 O 3 ceramic and 40Cr steel were conducted using a cylinder on blocks wear tester under PAO oil and PAO+carbon nanotube (CNT) as lubricants and at applied loads of 220 N and 520 N as well. The results show that the frictional coefficient of these three materials at 520 N are lower than at 220 N and that 20 vol% C f /Al 2 O 3 composite presents the lowest frictional coefficients. The wear resistance of 20 vol% C f /Al 2 O 3 is at least 10 times higher than 40Cr and 1.8 times higher than Al 2 O 3 in both PAO oil and PAO+carbon nanotube(CNT) lubricants. The wear mechanisms of these three materials are different. 40Cr presents ploughing and local deformation and even tearing, Al 2 O 3 shows spalling and grinding, and 20 vol% C f /Al 2 O 3 demonstrate slight spalling and shallow ploughing. These results show that in-situ transformed carbon fibres play a toughening role in Al 2 O 3 ceramic and the PAO+CNT lubricant has better lubricative role than PAO oil.