Evaluation of Corrosion Behavior and In Vitro of Strontium-Doped Calcium Phosphate Coating on Magnesium

This study investigated the biocompatibility of strontium-doped calcium phosphate (Sr-CaP) coatings on pure magnesium (Mg) surfaces for bone applications. Sr-CaP coated specimens were obtained by chemical immersion method on biodegradable magnesium. In this study, Sr-CaP coated magnesium was obtained by immersing pure magnesium in a solution containing Sr-CaP at 80 °C for 3 h. The corrosion resistance and biocompatibility of magnesium according to the content of Sr-CaP coated on the magnesium surface were evaluated. As a result, the corrosion resistance of Sr-CaP coated magnesium was improved compared to pure magnesium. In addition, it was confirmed that the biocompatibility of the group containing Sr was increased. Thus, the Ca-SrP coating with a reduced degradation and improved biocompatibility could be used in Mg-based orthopedic implant applications.

Influence of ultrasound on the synthesis of silver nanoparticles by galvanic replacement in sodium polyacrylate solutions

Sonogalvanic replacement and galvanic replacement synthesis of silver nanoparticles (AgNPs) by magnesium scrap in sodium polyacrylate solutions were studied. It was found that during these processes in NaPA solutions silver is practically not deposited on the magnesium surface. Sodium polyacrylate provides stabilization of AgNPs with the formation of yellow solutions with maximum absorption of ~415 nm. It is shown that sonogalvanic replacement synthesis of AgNPs occurs due to the simultaneous course of galvanic replacement by magnesium and sonoreduction of Ag (I) by radicals and reducing agents. The rate of sonogalvanic replacement synthesis of AgNPs is 20-30% higher compared to galvanic substitution by mechanical stirring.

Effect of Compressive Residual Stress on Film Formed by Mechanochemical Multifunction Cavitation Processing

Recently, mechanochemical multifunction cavitation (MC-MFC) was developed to improve the corrosion resistance of the magnesium surface. MFC is a technology that combines water jet peening and ultrasound cavitation. MC-MFC is a technology that adds phosphoric acid to water. It can improve the corrosion resistance by forming a phosphate film on the Mg surface. Conventional anodic oxidation, plating, and chemical vapor deposition can improve corrosion resistance by forming a film on the Mg surface, but it is difficult to improve characteristics such as compressive residual stress on the surface. MFC-treated surfaces have previously imparted various properties such as imparting compressive residual stress necessary to improve the fatigue strength to Al alloys and Cr-Mo steels. In this study, the effect of film formed on MC-MFC processed surface on compressive residual stress was investigated.

Decorative Concrete with the Addition of Highly Dispersed Organogenic Calcite (Chalk) in the Landscape Architecture of the Modern City

One of the main components of urban design and landscape architecture that shapes and emphasizes the urban environment are small architectural forms. These elements of landscape architecture are used outdoors, so the material is influenced by a variety of atmospheric phenomena (temperature fluctuations, insolation, etc.). The results of the experiments showed that increased water resistance rates reduce the degree of exposure of the aggressive liquid medium, in particular sulfate and magnesium surface and groundwater, and frost resistance create conditions for the operation of these samples outdoors. The whiteness of the obtained results indicates that the obtained composition of concrete can be used as decorative with the addition of colored pigments.