Abstracts Book - IMRC 2018

• SF2-P018
EFFECT OF TIME AND BALL-MILLING SPEED ON THE STRUCTURE
AND ELECTRICAL PROPERTIES OF (CO, DY, TA)-DOPED SNO2
VARISTORS
Martin Itzcoatl Miranda Lopez 1 , Marla B. Hernandez 1 , Patricia Zambrano Robledo 1 , Laura
García Ortiz 1 , Cristian Gómez Rodríguez 1 , Sergio Garcia Villarreal 2 , Josue A. Aguilar Martinez 1
1 Universidad Autónoma de Nuevo León, Centro de Investigación e Innovación en Ingeniería
Aeronáutica, Mexico. 2 Universidad Autónoma de Coahuila, Facultad de Metalurgia, Mexico.
In this work, the effect of different milling parameters (speed and time)
on repeatability of structure and electrical properties of ceramic varistors was
evaluated. High-energy ball milling was the method used to obtain SnO 2
varistors doped with Co 3 O 4 , Dy 2 O 3 and Ta 2 O 5 . Processing conditions of 100, 300,
and 600 rpm and 20, 60 and 180 min were used as speed and time ball-milling
parameters, respectively. Microstructure of the samples was characterized by
scanning electron microscopy (SEM) as well as X-ray diffraction
(XRD). Repeatability of the electrical properties was measured by statistical
analysis using standard deviation. A wide range of values for breakdown electric
field (946.45 to 4313.46 V/cm) and nonlinear coefficient (3.02 to 8.58 units) were
obtained. The lowest values of standard deviation were achieved with time and
ball-milling speed of 60 min and 300 rpm respectively. According to results, the
existence of an equilibrium between speed and time that yielded good
homogenization of the dopants over the SnO 2 matrix is discussed. This study
proffers valuable information for optimizing the ball-milling process.
Acknowledgment:
A sincere acknowledgment to the National Science and Technology Council of
Mexico (CONACYT) for the economic support.
Keywords: Varistors, High-energy milling, tin dioxide
Presenting authors email: martin.fcfm@gmail.com