In this study, Fe-Ag and Fe-Au composites were fabricated by powder metallurgy using spark plasma sintering. Their microstructures, mechanical properties, and biocorrosion behavior were investigated by using optical microscopy, X-ray diffraction, environment scanning electronic microscopy, compressive test, electrochemical measurements, and immersion tests. Microstructure characterization indicated that the as-sintered iron-based materials obtained much finer grains than that of as-cast pure iron. Phase analysis showed that the Fe-Ag composites were composed of α-Fe and pure Ag phases, and Fe-Au composites consisted of α-Fe and Au phases. Compressive test showed that the improved mechanical strengths were obtained in as-sintered iron-based materials, among which the Fe-5 wt %Ag exhibited the best mechanical properties. The electrochemical and immersion tests revealed that the addition of Ag and Au could increase the corrosion rate of the iron matrix and change the corrosion mode into more uniform one. Based on the results of cytotoxicity evaluation, it was found that all the experimental material extracts performed no significant toxicity on the L-929 cells and EA. hy-926 cells, whereas a considerable inhibition on the proliferation of vascular smooth muscle cells was observed. The hemocompatibility tests showed that the hemolysis of all the experimental materials was within the range of 5%, which is the criteria value of biomaterials with good hemocomaptibility. The amount of platelet adhered on the surface of as-sintered iron-based materials was lower than that of as-cast pure iron, and the morphology of platelets kept smoothly spherical on the surface of all the experimental materials.

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Designing novel phase change materials (PCMs) is of vital importance in achieving the sustainable development of energy. Here, we facilely prepare a series of novel multiple solid–solid PCMs (SSPCMs, EPPa‑X systems) by blending paraffin, epoxy resin with crystalline side chains (D18), and poly­(propylene oxide)­diamine together followed by a one-pot curing process. Strong intermolecular forces between paraffin and D18 (based on their good compatibility) and a reliable three-dimensional (3-D) cross-linking network of epoxy resin form a unique encapsulation mechanism, which provides the EPPa‑X SSPCMs with excellent shape-stable properties and superior thermal stability (remain stable below 180 °C) without sacrificing too much latent heat of paraffin (only 1.6% latent heat loss). Due to the combination of two melting processes at 36 and 60 °C derived from D18 and paraffin, respectively, the latent heat of the EPPa‑50 system is high, up to 152.6 J/g. Besides, the supercooling extent of D18 decreased from 13.6 to 10.5 °C with the addition of paraffin due to the heterogeneous nucleation effect. The novel EPPa‑X SSPCMs possess tremendous potential for a wide range of applications due to their facile preparation, low cost, high reliability, and excellent phase change properties, while the unique encapsulation mechanism may open a new door for preparing other novel types of PCMs.