LUBRICITY OF SRXCA1-XCUOY POWDERS DURING OIL LUBRICATION

Double oxide,SrxCa1-xCuOy has a layered structure in which Ca(Sr) is s andwiched between CuO2 layers. This crystal structure is expected to g ive low friction due to its low shear strength between laminas, In thi s work, various kind of SrxCa1-xCuOy with x=0.0 to 1.0 were prepared f rom SrCO3, CaCO3 and CuO by sintering method. The compositions of thes e products were examined by X-ray diffraction. The sample powders were blended in oil (squalane) and grease, and their load carrying capacit ies were evaluated by a cylinder-on-plate type tribometer and a four-b all machine, respectively. As a result of the tests, SrxCa1-xCuOy with x=0.0, 0.14, 0.90 and 1.0 showed low friction (about 0.1) and high lo ad carrying capacity (4900 N). It was found from SEM and EPMA results that the worn surface was smooth, and that a thin solid lubricating hi m containing Ca, Sr and Cu was formed on the rubbing counterface. Also , the oxides with x=0.9 and 1.0 showed superior properties under extre me pressure in four-ball machine testing.