Shell isolated nanoparticle enhanced Raman spectroscopy (SHINERS) studies of steel surface corrosion

Evaluation of N and S Codoped Carbon Dots as an Environment Friendly and High-Efficiency Inhibitor for X65 Steel in an Acidic Medium

The high content of nitrogen and sulfur-doped carbon dots (N, S-CDs) was designed to prevent the corrosion of X65 steel in an acidic medium. The corrosion-inhibiting abilities of related nanomaterials for X65 steel were acquired by electrochemical experiments, and the corroded products were investigated by FT-IR, XPS, and Raman analysis. The conclusions confirm that the N, S-CDs are a high-efficiency inhibitor. When the concentration is 200 mg/L, the inhibitive efficiency of X65 steel can reach up to 99.1% and it interacts with X65 steel through chemical and physical adsorption. Additionally, results from the spectroscopic studies show that the S-group is the main contributor to the chemical adsorption process.

Long-Life and pH-Stable SnO2-Coated Au Nanoparticles for SHINERS

Shell-isolated nanoparticles (SHINs) with a 37 nm gold core and an 11 nm tin dioxide (SnO₂) coating exhibited long-life Raman enhancement for 3 months and a wide pH stability of pH 2-13 in comparison with conventional SiO₂-coated SHINs. Herein, Au-SnO₂ is demonstrated as a more durable SHIN for use in the technique Shell-Isolated Nanoparticles for Enhanced Raman Spectroscopy (SHINERS).

Structural and Micromechanical Properties of Nd:YAG Laser Marking Stainless Steel (AISI 304 and AISI 316)

The purpose of this study is to examine the microstructure and micromechanical properties of pulsed-laser irradiated stainless steel. The laser marking was conducted for AISI 304 and AISI 316 stainless steel samples through a Nd:YAG (1064 nm) laser. The influence of process parameters such as the pulse repetition rate and scanning speed have been considered. The microstructures of obtained samples were analyzed using confocal optical microscopy (COM). The continuous stiffness measurements (CSM) technique was applied for nanoindentional hardness and elastic modulus determination. The phase compositions of obtained specimens were characterized by X-ray diffraction (XRD) and confirmed by Raman spectroscopy. The results revealed that surface roughness is directly related to overlapping distance and the energy provided by a single pulse. The hardness of irradiated samples changes significantly with the indentation depth. The instrumental hardness H_IT and elastic modulus E_IT drop sharply with the rise of the indentation depth. Thus, the hardness enhancement can be observed as the indentation depth varies between 100–1000 nm for all exanimated samples. The maximum values of H_IT and E_IT were evaluated for the region of small depths (100–200 nm). The XRD results reveal the presence of iron and chromium oxides due to irradiation, which indicates a surface hardening effect.