Sintering Behavior and Mechanical Properties of Mullite Fibers/Hydroxyapatite Ceramic

Abstract

The effect of fiber content and sintering temperature on sintering behavior and mechanical properties of mullite fibers/hydroxyapatite composites was studied. The composites were fabricated by hydrothermal synthesis and pressureless sintering. The amount of fibers was varied from 5 wt % to 15 wt % through hydrothermal synthesis, mullite fibers and hydroxyapatite composite powders were subsequently sintered at temperatures of 1150, 1250, and 1350 °C. The composites presented a more perturbed structure by increasing fiber content. Moreover, the composites experienced pore coalescence and exhibited a dense microstructure at elevated temperature. X-ray diffraction indicated that the composites underwent various chemical reactions and generated silicate glasses. The generation of silicate glasses increased the driving force of particle rearrangement and decreased the number of pores, which promoted densification of the composites. Densification typically leads to increased hardness and bending strength. The study proposes a densification mechanism and opens new insights into the sintering properties of these materials.

Effect of zirconia-mullite incorporated biphasic calcium phosphate/biopolymer composite scaffolds for bone tissue engineering

“…The adsorption band at 1075 and 791 cm −1 is due to the bending vibration of Si-O-Si while the band at 960 cm −1 is due to the Si-O vibration in the SiO 2 [36,43,44]. The peaks at 542 cm −1 is associated with the Si-O-Al vibration [24,44]. The band in 400-600 cm −1 region is due to the vibration of the blending of the silico-and alumino-silico oxygen bridges [24,44].…”

“…The peaks at 542 cm −1 is associated with the Si-O-Al vibration [24,44]. The band in 400-600 cm −1 region is due to the vibration of the blending of the silico-and alumino-silico oxygen bridges [24,44]. The FT-IR spectrums for the as-synthesized BCPZAS25, BCPZAS50 and BCPZAS75 composites with Chi/Alg-PCL polymer matrix exhibit the typical absorption bands of BCP (500-1100 cm −1 ), ZAS (400-600 cm −1 ) and of the organic groups in the polymers species.…”

“…ZAS are generally biologically inert, remain stable after being implanted in human body and do not cause any rejection [21][22][23][24][25]. They have been considered as some of the most hopeful candidate materials for reinforcing ceramic materials.…”

Microstructure and Mechanical Properties of Titanium–Equine Bone Biocomposites

“…For accuracy, the mean average values of the elastic modulus were calculated from ultrasonication method and nanoindentation curves. The increase in Vickers hardness by means of EB contents is because the hardness of hydroxyapatite contained in EB (nanohardness of 5-6 GPa and Vickers hardness of 460-480 HV) is higher than that of the Ti matrix (nanohardness of ~2 GPa and Vickers hardness of 350-400 HV) [41][42][43][44]. In addition, nanoscale hydroxyapatite was uniformly dispersed in the Ti6Al4V matrix, thereby strengthening particle effects on the hardness increment.…”

Effect of Urchin-Like Mullite Whiskers on the High-Temperature Performance of Porous SiO2-Based Ceramic Molds

“…In fact, many methods, including mineralizer addition [8], high solid loading [4], infiltration strengthening [9], as well as fiber or whisker addition [10,11,12], have been used to improve the high-temperature strength of SiO 2 -based ceramic molds in much research. Mullite whisker reinforcement is one of the most effective high-temperature strengthening methods due to its numerous advantages, including high melting point, chemical inertness, and excellent comprehensive mechanical properties [13,14,15] . Mullite whiskers can be either added to or synthesized in SiO 2 -based ceramic.…”