Investigation into the wear behaviour of Stellite 6 during rotation as an unlubricated bearing at 600 °C

• Published in: Tribology international Vol. 44; no. 12; pp. 1589 - 1597
• Main Authors: Wood, P.D., Evans, H.E., Ponton, C.B.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2011; Elsevier
• Subjects: Applied sciences; Bearing; Bearings, bushings, rolling bearings; Drives; Exact sciences and technology; Fracture mechanics (crack, fatigue, damage...); Friction, wear, lubrication; Fundamental areas of phenomenology (including applications); Glaze; Machine components; Mechanical engineering. Machine design; Physics; Solid mechanics; Stellite 6; Structural and continuum mechanics; Wear; Glaze; Wear; Stellite 6; Bearing; Stellite; Oxide layer; Rupture; Cobalt; Dry friction; Ceramic glaze; Cobalt base alloys; Chromium oxide; Wear layer; Plain bearing; Scaling; Deposit formation; Diffusion; Diffusion coatings; Tribology
• ISSN: 0301-679X; 1879-2464
• DOI: 10.1016/j.triboint.2011.02.011

The wear behaviour of Stellite 6 was studied during rotational sliding in a bespoke bearing rig at 600 °C for times between 2 min and 12 h. Six stages of wear were identified: (i) formation of a mixed oxide ‘glaze’, (ii) cobalt and chromium elemental diffusion to the ‘glaze’ surface forming chromium- and cobalt-dominated oxide layers, (iii) oxygen diffusion into the ‘glaze’ leading to a chromium-dominated oxide layer at the ‘glaze’/substrate interface, (iv) spallation of the ‘glaze’ through chemical failure, (v) re-formation of the ‘glaze’ and (vi) elemental diffusion within the ‘glaze’, again resulting in discrete oxide layer formation. ► The wear properties of Stellite 6 were investigated in a bespoke bearing rig at 600 °C. ► Wear protective oxide films often referred to as ‘glazes’ were formed. ► During the formation of the ‘glazes’ discrete oxide films were formed within them. ► Eventually spallation of the ‘glaze’ occurred through chemical failure. ► A new ‘glaze’ was regenerated from the wear debris.