Effects of zirconium source and content on zirconia crystal form, microstructure and mechanical properties of ZTM ceramics

Influence of zirconia on the sintering behaviour and mechanical properties of reaction-sintered mullite-based composite ceramics

“…The significant increase about bulk density after sintering at 1560℃ is attributed to the dense structure formed by the interleaving of rod-like mullite and the increasing amount of liquid phase filled the pores. Also, the slight reduction in bulk density at https://doi.org/10.1180/clm.2022.25 Published online by Cambridge University Press 1500-1540 °C is related to the expansion of secondary mullite formation and the phase transition of zirconia, i.e., t-ZrO2 to m-ZrO2 during cooling (Cui et al, 2020;Lian et al, 2021b). This phase transition results in volumetric expansion and decreases the bulk density.…”

Mechanical properties of in situ synthesized mullite‐based composite ceramics with three‐dimensional network structure

“…The samples have a dimension of 36 mm × 4 mm × 3 mm. The calculation formula is given as follows 37 : $$\begin{equation}{\sigma _f} = \frac{{3FL}}{{2b{h^2}}}\end{equation}$$where $${\sigma _f}$$ refers to the flexural strength (MPa), $$F$$ is the largest load (N), $$L$$ is the span length of the supporting points, $$b$$ is the width (mm), and $$h$$ is the height (mm) of the sample.…”

“…Five samples were tested to obtain an average value. The following equation calculated the fracture toughness 37 : $$\begin{equation}{K_{IC}} = {\rm{\;}}\sigma Y{\rm{\;}}\sqrt a = \frac{{FL}}{{a{b^{3/2}}}}{\rm{\;}}f{\rm{\;}}\left( {c/b} \right)\end{equation}$$ $$\begin{eqnarray} f{\rm{\;}}\left( {c/b} \right) &=& 2.9{\rm{\;}}{\left( {c/b} \right)^{1/2}} - 4.6{\left( {c/b} \right)^{3/2}} + 21.8{\left( {c/b} \right)^{5/2}}\nonumber \\ && -\, 37.6{\left( {c/Wb} \right)^{7/2}} + 38.7{\rm{\;}}{\left( {c/b} \right)^{9/2}}\end{eqnarray}$$where L is the span (32 mm), a is the thickness (mm), b is the width of the sample, and $$c$$ is the depth of the incision. The rest symbols and meanings are the same as those in the flexural strength formula.…”

“…The samples have a dimension of 36 mm × 4 mm × 3 mm. The calculation formula is given as follows 37 :…”

“…Five samples were tested to obtain an average value. The following equation calculated the fracture toughness 37 :…”