Friction and wear characteristics of Haynes 25, 188, and 214 superalloys against Hastelloy X up to 540 °C

Official URL: http://dx.doi.org/10.1007/s11249-011-9912-5

As demand for more power increases, com- pression ratios, and operating temperatures keep rising. High speeds combined with high temperatures make tur- bomachinery sealing applications even more challenging. In order to confirm sufficient service life material pairs should be tested under conditions similar to engine oper- ating conditions. This study presents high temperature friction and wear characteristics of cobalt/nickel superal- loys, Haynes 25 (51Co–10Ni–20Cr–15W), Haynes 188 (39Co–22Ni–22Cr–14W), and Haynes 214 (75Ni–16Cr– 3Fe–0.5Mn) sheets when rubbed against Hastelloy X (47Ni–22Cr–18Fe–9Mo) pins. Tests are conducted at 25, 200, 400, and 540 °C with a validated custom design linear reciprocating tribometer. Sliding speed and sliding distance are 1 Hz and 1.2 km, respectively. Friction coefficients are calculated with friction force data acquired from a load cell. Wear coefficients are calculated through weight loss measurements. Results indicate that Haynes 25 (H25) has the lowest friction coefficients at all test temperatures. Above 400 °C, H25 and Haynes 188 (H188) exhibit the best wear resistance. Protective cobalt oxide layers are formed on the H25 and H188 at 540 °C in addition to nickel, chrome, and tungsten oxides. Although, it has better oxidation resistance, Haynes 214 has relatively higher wear rates than other tested materials especially at low temper- atures. However, its wear performance improves beyond 200 °C.