국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Tribological Characteristics of Hot-Pressed Self-Lubricating Composites
저자	Mineo SUZUKI, Makoto NISHIMURA
Keyword	Self-lubricating composite; Friction test; Hot-press; Molybdenum disulfide; High temperature
URL	http://send.nal.go.jp/send/jpn/dlfile.php3/naltr01160?doctype=7&filetype=20&path0=naltr01160&path1=pdf&path2=naltr01160.pdf
보고서번호	NAL TR-1160
발행년도	1992.5
출처	NAL (National Aerospace Laboratory of Japan)
ABSTRACT	ybdenum disulfide(MoS2),refractory metal oxide(MoO3,MoO2,WO3,WO2,Ta2O5,or Nb2O5),and refractory metal(Mo,W,Ta,or Nb).Friction tests were performed in a vacuum,in nitrogen and in air atmospheres using ring-on-disk type friction testsers.The best material composition under the applied test conditions(contact pressures of 0.5-4 MPa and sliding speeds of 0.11-0.55 m/s)was found to be MoS280걪?MoO210걪?Nb10걪.In a vacuum,this composite showed a coefficient of friction of less than 0.07 and a specific wear rate of less than 10-11 mm3/N갋mm.Good tribological performance was also obtained with MoS280걪?Nb2O510걪?Nb10걪,MoS280걪?MoO210걪?Mo10걪 and MoS280걪?MoO220걪.For the composites showing good tribological performance,a thin,uniform transfer film was formed on the steel ring surface.X-ray diffraction results showed that Mo2S3 was present in almost all the composites;thereby suggesting that MoS2 partially dissociated into Mo2S3 during the hot-press process.It was also found that the addition of the refractorr metal promoted both the dissociation of MoS2 and the chemical reaction among the involved species.Sliding bearings fabricated from the best composites,being determined from friction test results,were run against 304 stainless steel shafts at temperatures up to 450걢C.Bearing wear was slight at less than 100걢C,and markedly increased at 300걢C.After being subjected to 450걢C testing,a weight loss of the shafts was observed.An X-ray Photoelectron Spectroscopy(XPS)analysis showed that a chamical reaction occurred between the composite and the steel shaft,causing material transfer from the shaft to the bearing.The composites showed no abnormal outgassing at high temperature,thus they are promising for use in high temperature vacuum condition,if mated with a counterpart which does not chemically react with them.