Surface Morphology Characteristics and Improvements on Corrosion Resistance in Anodized Mg-Al Alloys as a Result of Sealing Treatments

2005 ◽  
Vol 486-487 ◽  
pp. 129-132 ◽  
Author(s):  
Seong Jong Kim ◽  
Jeong Il Kim ◽  
Masazumi Okido

The effects of sealing solutions on the corrosion resistance of anodized Mg-Al alloys were investigated. As the proportion of Mg(OH)2 increases with the increase in the NaOH concentration, the corrosion potential improves. The sealing effects were further improved by increasing the temperature of distilled water, the pH of solutions, and the proportion of Mg(OH)2 present in the anodic film.

2005 ◽  
Vol 486-487 ◽  
pp. 125-128 ◽  
Author(s):  
Seong Jong Kim ◽  
Seok Ki Jang ◽  
Jeong Il Kim

The effects of the duration of potentiostatic anodizing on the corrosion resistance and surface morphology of anodic oxide films formed on Mg-Al alloy (AZ91) in 1 M NaOH were investigated. With the formation of an anodic film, the current density decreased gradually, started to stabilize at 300 s, and was relatively constant at 600 s. These results may be related to the increased time for catalysis of the active dissolution reaction, which not only enlarges the area covered by the anodic film, but also produces a more coherent, thicker film. The reference corrosion potentials of the anodic oxide film for AZ91 shifted in the noble direction with time. In general, the corrosion resistance characteristics were improved with anodizing time.


2017 ◽  
Vol 68 (9) ◽  
pp. 1974-1977
Author(s):  
Silvia Izabella Pop ◽  
Dana Cristina Bratu ◽  
Violeta Valentina Merie ◽  
Mariana Pacurar ◽  
Catalin Petru Simon ◽  
...  

The objective of this study was to analyse morphological and surface topography variations of two types of mini-implants after using different chemical and physical cleaning methods and autoclaved sterilization. One hundred mini-implants from two different manufacturers were used in this study. The mini-implants from each manufacturer were divided in five groups, each consisting of ten samples: G0 new, unused, G1 ultrasonically cleaned, G2 chemically cleaned, G3 sandblasted, G4 cleaned with distilled water. SEM analyses of the mini-implants were performed. Only procedures used in samples from group G2 and G3 removed the tissue remains from the mini-implants surface.


2018 ◽  
Vol 25 (02) ◽  
pp. 1850052 ◽  
Author(s):  
GAO PINGPING ◽  
OUYANG CHUN ◽  
XIE ZHIYONG ◽  
TAO TAO

The Ni-P/TiN coating was used as bipolar plate by electroless plating on Ti. Surface morphology and phase structure of the coatings were characterized by SEM and XRD, respectively. Corrosion resistance of Ni-P and Ni-P/TiN coating was measured in the simulated solution of Proton exchange membrane fuel cells (PEMFCs). The interfacial contact resistance (ICR) was conducted by applied different forces. SEM images indicated that the particles of core–shell structure were formed on the surface of coating on Ti substrate. The core–shell structure was composed of TiN core and Ni-P electroless plating shell. Compared with Ni-P coatings, the Ni-P/TiN coating showed better corrosion resistance behaviors and low ICR (below 10[Formula: see text]m[Formula: see text][Formula: see text] cm[Formula: see text] under pressure of 200 N/cm[Formula: see text]. TiN particles and distribution of core–shell were in favor of the formation of coating and compact surface morphology. The good conductivity was attributed to the compact surface morphology of coating. The Ni-P/TiN coating showed excellent interfacial conductivity and good corrosion resistance at applied high potential in simulated solution of PEMFCs.


2012 ◽  
Vol 548 ◽  
pp. 101-104 ◽  
Author(s):  
W. Shao ◽  
D. Nabb ◽  
N. Renevier ◽  
I. Sherrington ◽  
J.K. Luo

Ni-carbon nanotubes nanocomposite coatings were obtained from a Watts bath containing uniformly dispersed carbon nanotubes (CNTs). The surface morphology was investigated by the SEM images of coatings. The mechanical property and corrosion resistance of the nanocomposite coatings were investigated. This study revealed these CNTs reinforced Ni nanocoatings have improved mechanical and corrosion property.


Author(s):  
SANDEEP MALIK ◽  
VINEET KUMAR

In this work, the experimental investigation of the surface integrity and biomechanical properties of the superficial layer obtained by wire electrical discharge machining (W-EDM) of Ti-6Al-4V alloy for biomedical application has been carried out. The surface morphology and elemental composition of the superficial layer have been investigated by field-emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) techniques. The micro-mechanical behavior in terms of compressive strength and surface hardness was studied using the micro-pillar and nano-indentation technique. The corrosion resistance and in vitro bioactivity have been investigated using electrochemical and immersion test. Morphological analysis showed that surface morphology and superficial layer thickness were affected by peak current, pulse-duration and pulse-interval. The niobium (Nb)-rich layer was developed in superficial layer zone. The low peak current (3–6[Formula: see text]A), low pulse-duration (5–10[Formula: see text][Formula: see text]s) and high pulse-interval ([Formula: see text]s) have been recommended for better surface morphology and thin superficial layer (ranging from 4–6[Formula: see text][Formula: see text]m) free from surface defects. The micro-pillar and nano-indentation results showed that the superficial layer comprised of a brittle structure that improved the mechanical properties of the layer and the compressive strength was measured to be 1198 MPa. The corrosion resistance analysis revealed that the Nb-rich layer in the superficial layer improved the corrosion resistance and bioactivity. Excellent apatite growth has been found in the W-EDM-processed zone. The W-EDM can be used for the biomedical industry as a potential surface engineering technique.


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