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K. L. Meena and T. S. Srivatsan
increases the tetragonal phase. This also aids in contributing to the observed improvement in fracture toughness of the sintered samples. However, the indentation load
used was essentially the same for the composite samples developed using the techniques of conventional sintering and microwave sintering. The fracture toughness
value obtained using the macro-Vickers indenter for the ATZ composites that were
synthesized using the technique of conventional sintering was 4.9 ± 0.12 MPam
1/2
and the microwave sintering technique was 5.2 ± 0.15 MPam
1/2 , for an applied
indenter load of 98 N, and a dwell time of 15 s. This is shown in Fig. 6c. The
microwave (MW) sintering facilitates rapid heating that contributes to suppressing
grain growth resulting in a smaller grain size when compared to the sample obtained
by conventional sintering (CS). This increase in fracture toughness of the microwave
(MW) sintered ATZ sample can be safely attributed to the conjoint and mutually
competitive influences of higher densification and a suppression of grain growth.
Thermal Conductivity
The property of thermal conductivity refers to an ability to transmit heat through a
material. The ability for thermal conduction is made possible in materials due to the
movement of electrons coupled with vibrations of the lattice occurring at the fine
microscopic level. The hot disk sample holder and sensor thermal analyzer set up
are shown in Fig. 7a Thermal conductivity of the developed ATZ composite based
on the use of alumina (Al 2 O 3 ) to reinforce the YSZ matrix is shown in Fig. 7b.
Thermal conductivity is affected by the following three governing factors:
(a) Presence of grain boundaries,
(b) Internal porosity, and
(c) Presence and distribution of the impurities in the ceramic sample.
These factors can be carefully controlled and the level of thermal conductivity
achieved in the ceramic composite materials. The property of thermal conductivity
Fig. 7 a Hot disk sample holder and sensor thermal constant analyzer b Thermal conductivity of
the conventional sintered (CS) sample and microwave (MW) sintered sample. (Color figure online)
K. L. Meena and T. S. Srivatsan
increases the tetragonal phase. This also aids in contributing to the observed improvement in fracture toughness of the sintered samples. However, the indentation load
used was essentially the same for the composite samples developed using the techniques of conventional sintering and microwave sintering. The fracture toughness
value obtained using the macro-Vickers indenter for the ATZ composites that were
synthesized using the technique of conventional sintering was 4.9 ± 0.12 MPam
1/2
and the microwave sintering technique was 5.2 ± 0.15 MPam
1/2 , for an applied
indenter load of 98 N, and a dwell time of 15 s. This is shown in Fig. 6c. The
microwave (MW) sintering facilitates rapid heating that contributes to suppressing
grain growth resulting in a smaller grain size when compared to the sample obtained
by conventional sintering (CS). This increase in fracture toughness of the microwave
(MW) sintered ATZ sample can be safely attributed to the conjoint and mutually
competitive influences of higher densification and a suppression of grain growth.
Thermal Conductivity
The property of thermal conductivity refers to an ability to transmit heat through a
material. The ability for thermal conduction is made possible in materials due to the
movement of electrons coupled with vibrations of the lattice occurring at the fine
microscopic level. The hot disk sample holder and sensor thermal analyzer set up
are shown in Fig. 7a Thermal conductivity of the developed ATZ composite based
on the use of alumina (Al 2 O 3 ) to reinforce the YSZ matrix is shown in Fig. 7b.
Thermal conductivity is affected by the following three governing factors:
(a) Presence of grain boundaries,
(b) Internal porosity, and
(c) Presence and distribution of the impurities in the ceramic sample.
These factors can be carefully controlled and the level of thermal conductivity
achieved in the ceramic composite materials. The property of thermal conductivity
Fig. 7 a Hot disk sample holder and sensor thermal constant analyzer b Thermal conductivity of
the conventional sintered (CS) sample and microwave (MW) sintered sample. (Color figure online)