Abstracts Book - IMRC 2018

• SE4-O008
ELECTROCHEMICAL STUDY OF THE EFFECT OF THE ADDITION OF
MOLYBDENUM (3% AND 5% WEIGHT) TO A POWDER-
METALLURGICAL STEEL AISI 316 COMPARED TO A
CONVENTIONAL STEEL
Luz Adriana Cañas Mendoza 1,2 , Yaneth Pineda Triana 1 , Enrique Vera Lopez 1
1 Universidad Pedagógica y Tecnológica de Colombia, Facultad de Ingeniería, Colombia.
2 Universidad Tecnológica de Pereira, Facultad de Tecnología, Colombia.
The present work leads to the formulation of an austenitic stainless steel AISI
316 with Molybdenum additions, by means of the powder metallurgical process.
The Molybdenum was selected because it is recognized like an alloy element
that influences the passivity and the chemical resistance of the stainless steels
when these are under the action of chlorides and acidic electrolytes. To confront
the results obtained with a standard sample, the following ones were used like
study materials: AISI 316 conventional steel, AISI 316 powder metallurgical steel,
and the same powder metallurgical steel, with 3 % and 5 % in weight of
Molybdenum, which generates four alloys in study. The three powder
metallurgical alloys were made by means of conventional process, which
consisted of the formulation and mixture, uniaxial compression and sintering in
tubular furnace in atmosphere of nitrogen; it was used zinc stearate as lubricant.
The raw materials, the green compact and the sintered samples were
characterized previously to the electrochemical essays. Later to this both, the
alloys obtained for powder metallurgical process and a sample of conventional
steel, they were submitted to potentiodynamic anodic polarization essays, by
means of the software Gamry Echem Analyst, using H 2 SO 4 (1N) with 250 ppm of
NaCl like electrolyte; in this way the resistance to the linear polarization, the
speed of corrosion, and the degree of passivation were determined. In a
complementary way, the samples were submitted to immersion essays as the
ASTM G-1 standard, which establishes a immersion time of 350 hours; with this
procedure the loss of mass was measured and chemical analysis was realized
to the remaining electrolyte by means of Fluorescence of X-rays for the
determination of the dissolved species.
The microstructural aspects were analyzed by means of optical microscopy and
scanning electron microscopy, and it was observed an effect in the nature of the