THE EFFECT OF ANNEALING ON MICROSTRUCTURE OF STEEL NITRONIC 60
Nitronic 60 (UNS S21800) is a highly alloyed austenitic stainless steel with the increased content of manganese and silicon which has good mechanical and corrosion properties at high temperatures and loads. This paper presents the results of investigations of the influence of annealing process on the microstructure of steel Nitronic 60. Heat treatment consisted of annealing from 400 to 850 0 C for four hours followed by cooling in the water. The light and scanning electron microscope (with EDS analysis) were used for microstructure analysis. Analysis showed presence of sigma phase at higher temperatures. The sigma phase was precipited mainly at the austenite grain boundaries, δ/γ interface boundary and δ ferrite phase. Hardness testing showed increasing of hardness with precipitation of sigma phase.
Overview of Intermetallic Sigma () Phase Precipitation in Stainless Steels
The 𝜎 phase which exists in various series of stainless steels is a significant subject in steels science and engineering. The precipitation of the 𝜎 phase is also a widely discussed aspect of the science and technology of stainless steels. The microstructural variation, precipitation mechanism, prediction method, and effects of properties of 𝜎 phase are also of importance in academic discussions. In the first section, a brief introduction to the development and the precipitation characteristics (including morphologies and precipitation sites) of 𝜎 phase in stainless steels is presented. In the second section, the properties effect, prediction method, processing effect, elemental addition, retardation method and Thermo-Calc simulation of the 𝜎 phase in stainless steels are highlighted.
Analysis of molecular interactions in solid dosage forms; challenge to molecular pharmaceutics.
The molecular states of active pharmaceutical ingredients (APIs) in pharmaceutical dosage forms strongly affect the properties and quality of a drug. Various important fundamental physicochemical studies were reviewed from the standpoint of molecular pharmaceutics. Mechanochemical effects were evaluated in mixtures of APIs and pharmaceutical additives. Amorphization, complex formation and nanoparticle formation are observed after grinding process depending on the combination of APIs and pharmaceutical additives. Sealed-heating method and mesoporous materials have been used to investigate drug molecular interactions in dosage forms. Molecular states have been investigated using powder X-ray diffraction, thermal analysis, IR, solid state fluorometry, and NMR.