Japan Aerospace Exploration Agency Kakuda Space Center, Institute of Space Technology and Aeronautics
Japan Aerospace Exploration Agency Kakuda Space Center, Institute of Space Technology and Aeronautics
Japan Aerospace Exploration Agency Kakuda Space Center, Institute of Space Technology and Aeronautics
JAXA Special Publication: FY2004 Report of Joint Research Achievements of the Space Division of Institute of Aerospace Technology and Institute of Space and Astronautical Science: Basic Technologies of Space Transportation Systems
巻
JAXA-SP-05-010
ページ
49 - 52
発行年
2006-01-20
抄録（英）
In order to realize Liquid Oxygen (LO2)/Liquid Hydrogen (LH2) pump-fed rocket engines characterized by high durability, the cryogenic high-speed bearings used in the turbopumps must have high wear-resistance. These bearings made of SUS440C were self-lubricated with a glass cloth-reinforced PTFE retainer. In a previous study, the bearing exhibited excellent durability in at a speed of 50,000 rpm. XPS analysis indicated the intense formation of a chromic oxide (Cr2O3) layer (thickness, about 15 nm) beneath an extremely thin transferred lubricant-film. To reduce the bearing wear, the pre-formation of a thick Cr2O3 layer, which restrained metal-to-metal adhesion, seemed to be effective, because the untreated bearing had an extremely thin native Cr2O3 layer (about 2.5 nm). The purpose of this study is to evaluate the Cr2O3 layer chemically formed on the SUS440C ball. These results showed that a considerably thick Cr2O3 layer on a SUS440C surface was successfully formed by heat treatment at a low concentration of oxygen. Friction and wear of the Cr2O3 layer chemically formed was found to be better than that of the untreated ball in LN2.
SUS440C軸受における酸化クロム皮膜の評価
49056010.pdf
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