ABSTRACT
Ni alloys are used as the prominent industrial material for heat-resistance and corrosion-resistance. Out of them, Inconel has excellent properties for high-temperature heat-resistant equipment as an excellent material for equipment such as ultrahigh-temperature electric furnace and or boiler. However, Ni alloys used in various areas contain high-priced metals such as Ta, Nb, or Re and their use have been limited to industrial sector so far due to the price incompetence. In this study, the alloy Ni-28Cr-4Mo-2Ti was designed by electronic state calculation by replacing the expensive material of Ta and Nb in Inconel 625 with Ti. In order to compare the corrosion properties, they were intentionally corroded in a furnace at 500 °C for 3 months and potentiodynamic polarization method was used to check the corrosion rate. The validity of the results was also confirmed by using the values of atomic radius and electronegativity. As a result, it was confirmed that the newly designed alloy had superior corrosion resistance at higher temperature than Inconel 625.
ABSTRACT
In this work, we found the characteristics of an antibacterial TiAgN thin film coated on the pure titanium specimen via the physical vapor deposition process (PVD). TiAgN thin films were coated using TiAg alloy targets by arc ion plating method. Changing the process parameters, the surface analysis of TiAgN thin film was observed by FE-SEM and the force of adhesion was measured with Scratch Tester. The proliferation of human gingival fibroblast (HGF) cells was examined by XTT test assay and the antibacterial properties were investigated by culturing Streptococus Mutans (KCTC 3065) using paper disk techniques. At the result of experiment, cytotoxic effects were not found and the antibacterial effects against Streptococus Mutans were appeared over 5 wt% TiAgN specimens.
Subject(s)
Coated Materials, Biocompatible/pharmacology , Metal Nanoparticles/administration & dosage , Silver/chemistry , Silver/pharmacology , Streptococcus mutans/drug effects , Titanium/chemistry , Adsorption , Alloys/chemistry , Alloys/pharmacology , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/pharmacology , Cell Survival/drug effects , Cell Survival/physiology , Coated Materials, Biocompatible/chemical synthesis , Gases/chemistry , Materials Testing , Metal Nanoparticles/chemistry , Metal Nanoparticles/ultrastructure , Particle Size , Streptococcus mutans/physiology , Surface Properties , Titanium/pharmacologyABSTRACT
This study evaluated the antibacterial effect of a visible light reactive TiO2/Ag nanocomposite thin film on dental orthodontic wire (STS 304 wire). The growth of S. mutans and A. actinomycetemcomitans was suppressed on the specimens coated with TiO2/Ag compared to the uncoated specimens. The antibacterial effect of the TiO2/Ag nanocomposite thin film was improved under visible light irradiation.
Subject(s)
Anti-Bacterial Agents , Light , Nanocomposites , Orthodontic Appliances , Silver , Titanium , Microscopy, Electron, Scanning , Spectrophotometry, Ultraviolet , Spectroscopy, Near-Infrared , X-Ray DiffractionABSTRACT
The purpose of this study was to investigate the effects of heat treatment on the cystallinity of titanium nanotubes. The titanium nanotubes had diameters ranging from 90-95 nm, lengths between 400-500 nm, and thicknesses of 11 nm. After heat treatment at high temperatures, the diameter and length of the nanotubes decreased, whereas the thickness increased. The titanium nanotubes exhibited amorphous + anatase phases at 300 degrees C, anatase + rutile phases at 500 degrees C and a rutile phase at 800 degrees C.
