Brake fluids and corrosion resistance of aluminum alloys: a fundamental investigation

Abstract

"Top-notch disc brake systems typically include components which are designed using aluminium/silicon alloys. The corrosion resistance of such materials, while immersed in brake fluids, is only barely investigated in the literature, and regards only very few and case-specific examples. Following this, the manuscript investigates the corrosion resistance of a 42200 aluminium/silicon alloy in different brake fluids (BFs). In particular, five brake fluids comprising an increasing amount of water are investigated. Results are discussed in terms of corrosion potential (Ecorr) and corrosion current (Icorr) values of the alloy, as obtained from linear sweep voltammetry measurements. The suggested lab-scale approach is aimed at: a) proposing a preliminary investigation regarding the corrosivity of different BFs; and b) simulating the effect of the brake fluid ageing (e.g., increasing amount of water) on the corrosion resistance of the investigated 42200 alloy. It is demonstrated that the corrosion resistance of 42200 is strongly modulated by: a) the nature of the brake fluid in which it is immersed; and b) the amount of water comprised in each BF. Insights regarding the minimum amount of water which is necessary to modulate the electrochemical performance of each BF are proposed as well. "