Investigation of nanosized alumina‐binder feedstock rheology for ceramics injection molding (CIM) and survey spark plasma sintering of output green body to obtain transparent alumina

Abstract

The purpose of this work is to optimize the feed containing alumina-binder nanoparticles for ceramics injection molding to create transparent alumina parts.In this research, two Alumina with and without MgO as sintering aid fabricated via the spark plasma sintering method. Feed fluidity, fracture toughness, density, IR, and visible transmission of SPSed bodies of the sintered pieces were measured. Furthermore, a pin on the disc test was used on the disk to examine the alumina friction coefficient. The results of feed rheology showed that the sample prepared at 90 • C had the best conditions as a pseudoplastic fluid for the ceramic injection molding (CIM) method. The results showed that a combination of CIM and spark plasma sintering (SPS) methods cause more visible transmission than conventional SPS of alumina nanopowder. Also, the fracture toughness and hardness of as-obtained transparent alumina were in the range of 3.6 MPa m 0.5 and 20.1 MPa, respectively. The wear rate of the as-obtained transparent sample (4.5 × 10 −7 mm 3 /N m) was proportional to the alumina grain size (1-4 μm).

Gold–oxoborate nanocomposite‐coated orthodontic brackets gain antibacterial properties while remaining safe for eukaryotic cells

“…Thus, several antibacterial coatings have been proposed to reduce bacterial adherence on orthodontic appliances, such as titanium, silver, copper, zinc dioxides, or nanosilver and platinum 15–22 . Another approach is to replace steel with nanomaterial composites as bulk material for bracket manufacturing 23,24 . Although the antibacterial efficiency of the reported coatings is well documented, many present significant drawbacks, such as costly and complicated manufacturing processes or questionable biocompatibility, which heavily impede clinical application 22,25 .…”

“…[15][16][17][18][19][20][21][22] Another approach is to replace steel with nanomaterial composites as bulk material for bracket manufacturing. 23,24 Although the antibacterial efficiency of the reported coatings is well documented, many present significant drawbacks, such as costly and complicated manufacturing processes or questionable biocompatibility, which heavily impede clinical application. 22,25 Since gold nanoparticles (AuNPs) present excellent properties in the aspects mentioned above, they are a promising substrate for a medical-grade antibacterial coating.…”