Bioactive glasses (BG) possess significant bone-bonding and osteogenic properties that support their use for bone defects repair in orthopaedic and dental procedures. Recent advancement enables the manufacturing of BG-based scaffolds providing structural support during bone regeneration. Despite the wide number of studies on BG and BG-based materials, little information on their aging mechanisms and shelf life is available in the literature. In this study, the evolution of chemical species on BG-based foams was investigated via accelerated tests in the presence of CO₂ and humidity. The aging process led to the formation of carbonates (Na₂CO₃ and CaCO₃) and hydrocarbonates (NaHCO₃). The amount and composition of nucleated species evolved with time, affecting the structure, properties, and bioactivity of the scaffolds. This study provides a first structured report of aging effects on the structure and chemico-physical properties of bioactive glass-based scaffolds, offering an insight about the importance of their storage and packaging.

Characterizing powder feedstock is crucial for ensuring the quality and reliability of parts produced through metal additive manufacturing (AM). The morphology of particles impacts the flowability, packing density, and spreadability of powders, affecting productivity and part quality. A new methodology has been developed to classify particle morphological features in AM powder feedstocks, such as spherical or elongated shapes, and the presence of satellites and facets. This approach uses multiple descriptors for quantitative evaluation. The results from shape descriptors can vary based on image resolution, gray/color thresholding, and software algorithms. There are various commercial systems available for characterizing particle shape, some of which use images taken of static particles, while others use images of particles in motion. This diversity can lead to differences in powder characterization across laboratories with different equipment and methods. This paper compares results from a particle classification approach using two software programs that work with metallographic images with those from an automated static particle analyzer. While traditional methods offer higher resolution and precision, this study shows that automated systems can achieve similar particle shape classification using different shape descriptors and thresholds.

Bioactive glasses have been used for many years as bone graft substitutes in orthopedic and dental applications as well as an additive in toothpastes, cosmetics, and cosmeceutical products. The interest of using bioactive glass comes from its ability to dissolve and release dissolution products that stimulate bone regeneration. Porous bioactive glass scaffolds that can provide structural support while bone is growing into the structure have generated interest. However, little data is available in the literature on the effect of environmental conditions or sterilization treatments on the structure and properties of these materials. This study presents the evolution of the structure and microstructure of bioactive foams exposed to different accelerated and real‐time aging conditions and sterilization treatments. The results indicate that the material is relatively stable. For example, different sterilization methods (steam, ethylene oxide, hydrogen peroxide, gamma‐rays) have limited effect on the structure and properties of the foams. However, carbonate species may form on the surface of the material when exposed to CO₂ and humidity. Some carbonates dissolve rapidly in water and may impact the pH of the solution. Adequate packaging should limit the reaction of the bioactive glass with CO₂ and humidity and the formation of carbonate.

As cold spray additive manufacturing matures, significant efforts are being made to develop spray conditions for more challenging materials, thereby expanding the technology’s range of applications. One main challenge while using commercially available equipment is that, even under optimized conditions, deposition efficiency remains low for some materials. Powder particles that do not adhere are wasted, which can severely affect the process economics, especially in a mass production context and/or when expensive feedstocks are used. Powder recovery and reuse is a logical solution to mitigate this problem, yet few studies evaluate its feasibility and its impact on powder characteristics and ultimately coating performance. In this work, powder recovery was investigated for two cases: a Ni powder and a NdFeB-Al powder mix, used respectively for repair applications and for the fabrication of permanent magnets. A prototype recovery system was built, achieving a recovery efficiency of up to 75%. The powders were recovered after up to four spray runs, and their morphology and size distribution were characterized. The magnetic properties of both powders and coatings were evaluated using hysteresis measurements. Although the process affects the particle size distribution and their magnetic properties, powders remain suitable for re-deposition for both materials. In particular, it was shown that NdFeB-Al mix maintains 97% of its initial magnetic performance under industrial operating conditions.