Effect of Acetic Acid on Wear Properties of Ferrous and Titanium-Based Materials under Ethanol Lubrication

Abstract

Disks of ferrous and titanium-based material were immersed and unidirectionally slid against a stainless steel pin in ethanol with or without acetic acid to evaluate the effect of acetic acid on wear. The disks were made of cast iron, stainless steel, titanium metal and particulate-reinforced titanium metal matrix composite sintered from mixed powder of Si₃N₄ (5 mass%), TiN (10 mass%) and Ti (85 mass%). In the absence of sliding, the stainless steel, titanium and composite showed good corrosion resistance but the cast iron exhibited galvanic corrosion. With sliding, the addition of acetic acid to the ethanol increased the wear of the ferrous materials but had little effect on the titanium-based materials. Morphological and chemical analyses of the worn surfaces revealed that acetic acid promoted anodic dissolution of iron on the sliding surfaces of the ferrous materials in ethanol. The results also indicated that titanium and the composite in ethanol with and without acetic acid primary underwent mechanical wear and chemical wear, respectively. The composite exhibited good corrosion and wear resistance in ethanol regardless of the presence of acetic acid.

Fig. 6 Specific wear rates of disks and pins: (a) disk and (b) SUS440C stainless steel pin. The symbols “^*” and “^**” indicate that the wear could not be calculated.