Wear prevention characteristics of binary oil mixtures

This work presents and discusses the results of wear prevention tests carried out with mixtures of a low viscosity polyalphaolefin (PAO 6) and two esters (TMP-05 and sunflower oil, SO), on a four-ball machine tester using the ASTM D 4172-88. Tests were done at three different loads: 264.6, 392 and 490 N. Test speed and time were 1200 rpm and 60 min, respectively. The ball test material was 12.7 mm diameter AISI 52100 steel, with a hardness of approximately 65 HRC. Wear scar diameter (WSD) was measured with an optical microscope. Results show that esters are excellent wear reducers when they are mixed with a low viscosity polyalphaolefin. The optimum ester percentages in PAO 6 were 5 and 15% for TMP-05 and SO, respectively. Better results than in pure PAO 6 occurred in all mixtures. The addition of esters (less than 15%) to PAO 6 hardly changed volume viscosity.