Compatibility of nickel and silver‐based brazing alloys with E85 fuel blends

Abstract

In this study, the corrosion behavior of AISI 304 fuel rail brazed joints in presence of ethanolic E85 fuel has been evaluated. The galvanic corrosion resulting from coupling steel and copper brazing alloys has been studied as it represents a potential risk for the functionality of the fuel rail and injectors. The corrosion can lead to nozzle clogging by the increase of level of solute metallic ions or rupture of the joint itself. Tests have been carried out both on specimens simulating the brazed joints and on real fuel rail component. Static immersion tests and static filling tests in standard gasoline, E85 and modified E85 fuels have been carried out. The latter have been prepared by adding aggressive reagent, such as acetic acid, sulfuric acid, and chlorides, to the E85 fuel. Tests have been carried out at room temperature and at 60 8C. Alternative brazing materials to copper alloys (nickel-and silver-based alloys) have also been tested, with the aim of comparing their corrosive resistance. From results here obtained, the nickel-based brazing alloys, which have been tested because of their intrinsic ability to passivate, have proved to be more resistant to corrosion than copper, but only during exposure to commercial E85 and at room temperature. Silver-based brazing alloys have shown poor resistance to corrosion and the tendency of soluted Ag ions to precipitate in presence of chloride ions.

Corrosion Behavior of Al in Ethanol–Gasoline Blends

“…However, alcohol absorbs water because it is highly hygroscopic and shows ethanol impurities (i.e., organic acids, esters, and ketones), which makes metallic materials that come in contact with ethanol-gasoline highly susceptible to corrosive attacks [1][2][3]. Numerous studies have been undertaken to evaluate the corrosion behavior of metallic materials used in components of vehicle fuel systems [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Bahena et al [18] evaluated the corrosion behavior of four metals, including pure aluminum, chromium steel carbon steel, and copper in a 20% ethanol-80-gasoline blend using both weight loss and electrochemical impedance spectroscopy.…”

Microgalvanic Corrosion Behavior of Cu-Ag Active Braze Alloys Investigated with SKPFM

“…For example, silver-based braze alloys typically have a lower corrosion rate in an industrial atmosphere than in a marine environment [2]. When used in settings where contact with certain types of fuel may occur, silver-based brazes have poor corrosion resistance that can ultimately lead to failure [3]. The effect of brazing on the corrosion behavior of the resultant parts (including parent materials) has not been widely investigated.…”

Effect of Ti and B microadditions on the hot ductility behavior of a High-Mn austenitic Fe–23Mn–1.5Al–1.3Si–0.5C TWIP steel

“…On the other hand, during DRX, grain boundaries migrate and microvoids initially formed at grain boundaries are isolated. Therefore, the coalescence of microvoids at grain boundaries is prevented and grain boundary decohesion is retarded [31]. Previous research works [26,27] on the study of the hot ductility of TWIP steels have shown different behaviors at the intermediate temperature range compared to most plain carbon and microalloyed steels.…”