The purpose of this work was to study the frictionaland wear behavior of alumina under scratching in variousenvironments. The scratch tests were performed at loads from 0.5to 50 N and a sliding velocity of V- 0.4 mm S-1 during 100 cyclesin water, paraffin oil and in laboratory air (humidity ~50%).Diamond standard spherical indenter was used as the contrabody.The acoustic emission, friction coefficient, wear losses and failuredevelopment in the scratch tracks were evaluated.It was found that the friction coefficient increased during somecycles and then a steady friction state with approximately constantvalue of the friction coefficient was reached in all environments.The maximal friction coefficient, (f=0.2), was in contact withparaffin oil, while the minimal value of f=0.09 was obtained in thewear test with water. The opposite effect was obtained in thedetermination of the wear rate. The width of the wear track wasmaximal and minimal in contact with water and paraffin oil,respectively. The trapping and agglomeration of wear particles wasobserved in the wear track under contact with air and water.Intergranular and transgranular fractures were found to be thedominant damage mechanisms in contact with paraffin oil.Close relation between signals of acoustic emission and frictionand wear properties was exhibited under different environmentalconditions. The bond between the trapped wear particles and thesubstrate was analyzed. It is supposed that the trapping of the wearparticles is caused by triboelectrification of alumina. This effectwas maximal in dry friction. Almost no trapping was observed incontact with paraffin oil.
刮伤铝
L. Rapoport、I. Lapsker
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1999
International Journal of Refractory Metals & Hard Materials
NSTL
