A SYSTEMATIC PROCEDURE TO STUDY HOT PRESSING AND SPARK PLASMA SINTERING KINETICS

Year 2017, Volume: 18 Issue: 2, 419 - 428, 30.06.2017

İsmail Özgür Özer , Çetin Meriç Güvenç

https://doi.org/10.18038/aubtda.305182

Abstract

A procedure for data collection and
processing was developed to conduct accurate kinetic analysis in pressure
assisted sintering techniques, such as hot pressing (HP) and spark plasma sintering
(SPS). Densification of MgAl₂O₄ by SPS was chosen as a
model system, where the kinetics were analyzed by utilizing the modified creep
equation. Displacement data used in the equation was gathered by path
measurement system (PMS) of the SPS equipment. Effects of temperature control
accuracy, load cell accuracy and resolution of the PMS on the reliability of
collected displacement data were evaluated. Dilution of the data in order to reduce
the noise in strain rate values caused by the low resolution of the PMS system,
which is only 10 μm, was observed to affect calculated stress exponents (n),
significantly. Different n values in the range of 1.7-2.8 in a narrow interval
of 83-86 % relative densities were found as a function of dilution degree. On
the other hand, differentiating the strain with respect to the time interval of
every single 10 μm displacement was shown to provide more consistent results. n
values of ≈2.2 with a standard deviation of 0.15 were calculated for the same
density intervals. 

Keywords

Formal sintering analysis, Modified creep equation

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