TITLE:
Evaluation of Additives as Corrosion Inhibitors/Antioxidants for High Quality Nano Emulsifiable Oils of Metalworking Fluids
AUTHORS:
Noura El Mehbad
KEYWORDS:
Lube Oil, Antioxidants, Antiwears, Sulphonates, Ethoxylates, Phase Transfere Catalysts
JOURNAL NAME:
Journal of Surface Engineered Materials and Advanced Technology,
Vol.4 No.3,
April
28,
2014
ABSTRACT: Surfactants used for
formulation metal working fluids. In the present paper, the inhibitive effect
of synthesized anionic surfactant P-decyloxy p-sodium sulphonateazobenzene with
chemical structure H21C10O-Ph-N=N-Ph-SO3Na and
1-ethyl-1-dodecyl-2-sulphonate-4-(hydroxyl ethyl)-piprazine on the corrosion of
carbon steel in sulphuric acid solution is measured by the weight loss method.
The relationships between the concentrations of these inhibitors and their
surface properties, thermodynamic
properties, surface coverage and inhibiting efficiency, have been investigated.
The results indicate that P-decyloxy p-sodium sulphonate azobenzene is
superior to 1-ethyl-1-dodecyl-2-sulphonate-4-(hydroxyl ethyl)-piprazine at
high acid concentration. These inhibitors blend with coupling agent to produce
water miscible cutting fluid. Values of surface tension of these additives
were measured in water phase and consequently CMC was determined for all
inhibitors. The efficiency of these inhibitors depends on their chemical
structure and the presence of hydrophilic group to association of the
surfactant with metal surface, hence very good wetting properties. The
anti-corrosion characteristic of surfactants increases with increasing polar
linkages in the aromatic moieties forming chelated and coordinated layer. This
is due to the increase in number of sites to chemisorption on the metal
surface. These studies have led to much clear evidence of the intimate
relationship between the chemical structure of the surfactants and their
efficiency. More confirmation for suggested mechanism was investigated by
measuring the area occupied per molecule of the surfactant at aqueous phase.
The results indicate that the amphoteric surfactant more efficient than anionic
surfactant. The antioxidants activities of different dosages of inhibitors were
evaluated and suggested mechanism according to their thermodynamics parameters.
The oxidation of the oil has been carried for different time intervals. The
degradation of the oil has been monitored by total acid formation.