Alternative to chromium: characteristics and wear behavior of HVOF coatings for gas turbine shafts repair (heavy-duty)

Oxidation Behavior of Tribaloy T-800 Alloy at 800 and 1,000 °C

“…Co-based Tribaloy Ò1 alloys are a group of superalloys used extensively as wearresistant and corrosion-resistant coating materials for industrial turbine applications [1][2][3]. A typical Tribaloy alloy is T-800 (Co-17.5Cr-28.5Mo-3.4Si, wt.%) which is employed for better abrasive wear resistance at service temperatures as high as 800°C.…”

“…Much attention has been paid to the wear resistance of Tribaloy alloys [2,7,8]. However, relatively few reports on the reaction mechanisms of T-800 oxidized at high temperatures are available.…”

Tribological properties of HVOF as-sprayed and heat treated Co–Mo–Cr–Si coatings

“…Several studies have already elucidated the tribological behaviour of HVOF-sprayed cermet coatings under very different conditions, such as dry and wet particles abrasion [5], slurry erosion [6], solid and liquid-solid particles impingement [7], dry sliding [8,9] and others [10,11]. In fact, in several cases, such coatings offer the best wear performances, thanks to the hardness conferred by carbide particles and to the toughness conferred by the metal matrix.…”

“…For instance, such coatings are being employed to coat or restore engine shafts. However, they have been seldom considered in literature: very few studies exist concerning their microstructural or tribological performances [9,[15][16][17][18][19][20][21]. They are known to be precipitation strengthening alloys [15], but they become mostly amorphous when thermally sprayed [15,17].…”

Effect of WC–10%Co–4%Cr coating on the Ti–6Al–4V alloy fatigue strength

“…However, electroplated baths produce hexavalent chromium, restricted by environmental legislation [9]. Therefore the development of alternative processes to manufacture wear resistant coatings is required [9][10][11].…”