Porous Hydroxyapatite Bioceramics Prepared by Polymeric Sponge Impregnation Process

Abstract

Porous hydroxyapatite bioceramics were obtained by impregnating the polyurethane sponge with rheologically optimized slurry. 6wt% bioglass was doped into hydroxyapatite to act as a sintering additive. Thermal analysis was used to study the pyrolysis process of the polyurethane sponge. Phase component and surface morphology were characterized by X-ray diffraction and scanning electron microscopy, respectively. It was found that hydroxyapatite was the main phase composition of the porous ceramics sintered at 1250°C. The porous bodies prepared had an open, uniform and interconnected structure with pore size of 200-400μm. The porous ceramics possessed high porosity of 70-80% and compressive strength of 2.3MPa. The precipitates formed on the surface of the porous ceramics might be bone-like apatite after immersion in a simulated body fluid for various periods.

3D Printing of cement composites

“…In order to address this, a number of researchers have tried to incorporate macroporosity into HA structures. 6 Bone grows into the pore structure, adding toughness to the implant, and eventually the HA implant material becomes completely integrated into the new bone structure. These 'scaffolds' can be made by a variety of approaches (e.g.…”

Survey of Reliability Research on 3D Packaged Memory

“…Qiang [141] used a finite element simulation to analyze the equivalent stress and equivalent plastic strain of 3D-Plus memory PCB components under random vibrations and temperature cycling. The results show that the design of the PCB screw fixation points was vital to the reliability of 3D-Plus memory PCB-level assembly.…”

“…In [53,[141][142][143][144], the reliability research of PiP packaging is mainly carried out via a combination of finite element simulation and test verification, but the number of research topics classified as thermal stress and hygrothermal stress is relatively lower than those classified as PoP and CoC packaging. In addition, due to the internal encapsulation structure of PiP packaging devices and the absence of movable components, reliability research on mechanical stress is only carried out after assembly at board level.…”

“…In addition, due to the internal encapsulation structure of PiP packaging devices and the absence of movable components, reliability research on mechanical stress is only carried out after assembly at board level. Such studies include analyzing the equivalent stress and plastic strain of printed board components of 3D-Plus memory under random vibrations and temperature cycling [141]. In terms of the reliability of solder joints subjected to thermal stress loads, the results of [142] show that there is a significant periodic change in the stress and plastic strain of solder joints, and the reliability of lead-free solder is greater than that of lead-based solder.…”

Effect of pressure on pore structure of porous FeAl intermetallics

“…For porous materials whose pore formation mechanism involves putting off the pore formation reagent, controlling the pore structure by pressure is difficult and may easily lead to environmental pollution [14][15][16]. Considering the Kirkendall effect [17][18][19][20], which is caused by the large diffusion discrepancy between Fe and Al elements in intermediate phases, numerous pores are produced along the diffusion direction of Al element because Al atoms diffuse faster than Fe atoms.…”