Article Per Year (5 Year)
p-Index From 2020 - 2025
0.659
P-Index
This Author published in this journals
All Journal Makara Journal of Science
Anawati, Anawati
Unknown Affiliation

Published : 3 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 3 Documents
Search

 1 
Improving the Surface Corrosion Resistance of AMX601 Magnesium Alloy by Acid–Alkaline Treatment Anawati, Anawati; Asoh, Hidetaka; Ono, Sachiko
Makara Journal of Science Vol. 24, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

A drawback of acid cleaning as surface finishing of magnesium (Mg) surface is the absence of a protective oxide film on its surface. Acid–alkaline treatment is proposed to enhance the surface corrosion resistance of AMX601 Mg alloy. Acid–alkaline treatment was conducted by first dipping the alloy in HNO3–H3PO4 solution and then immersing the al-loy in NaOH solution. The potentiodynamic polarization test in 0.9% NaCl solution at 37 °C revealed a nobler corro-sion potential of −1.36 VAg/AgCl and a lower corrosion current density of 36.0 µA•cm−2 of the acid–alkaline-treated spec-imen than the acid-treated (−1.44 VAg/AgCl, 89.7 µA•cm−2) and untreated (−1.52 VAg/AgCl, 40.0 µA•cm−2) specimens. Acid treatment induced a significantly higher surface roughness (20 µm) than acid–alkaline (10 µm) and grinding (0.5 µm) treatments because of the selective dissolution of the Mg matrix and the accumulation of intermetallic precipitates. The film formed on the acid–alkaline-treated specimen was thick and free of cracks, whereas that formed on the acid-treated specimen was thin and cleaved. The formation of a protective oxide film and the enrichment of cathodic intermetallic particles on the acid–alkaline-treated specimen enhanced the corrosion resistance of the surface.
Carbon dioxide-Induced Corrosion of AISI 4140 Steel in Acidified Artificial Geothermal Brine Anawati, Anawati; Izzat, Rayhan; Pragitta, Riene Kaelamanda; Hernandi, Rafli Ihsan
Makara Journal of Science Vol. 27, No. 1
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Carbon dioxide (CO2)-induced corrosion often occurs in the structural materials of geothermal industry. The presence of CO2 influences the formation of various corrosion products. This research investigates the effect of dissolved CO2 in acidic brines on the corrosion behavior of AISI 4140 steel at atmospheric pressure. The brines were the standard brine, Ca-free brine, and high-salinity brine. The corrosion behavior was studied using electrochemical and immersion tests. A cyclic polarization test showed that the corrosion rate was higher in dissolved CO2 brine than in non-CO2 brine, and an immersion test demonstrated a similar result. In the absence of CO2, the presence of Ca ions in the brine reduced the corrosion rate of the alloy from 26.8 to 24.6 mmpy and further to 20.7 mmpy in the high-salinity brine. A similar trend was demonstrated during immersion in the CO2-containing brine, with higher rates of 37.1, 30.9, and 24.9 mmpy for the Ca-free, standard, and high-salinity brines, respectively. However, the Ca ions and high-salinity brines induced a more localized corrosion as pit and filiform. A surface analysis using an optical microscope revealed that immersion in CO2 brines generated 4–10-fold higher surface roughness than the non-CO2 brines. In all specimens, a protective layer was not established during the tests. No new phase was detected using X-Ray diffractometer after the immersion test. Moreover, no tendency of passivation was observed in the reverse scan of the cyclic polarization test.
Enhanced Crack Resistance of Porous Anodic Aluminum Oxide Grown on a Tubular Substrate with the Additive Ethylene Glycol Sianturi, Manogari; Juwono, Ariadne Laksmidevi; Anawati, Anawati
Makara Journal of Science Vol. 29, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The growth of a porous anodic aluminum oxide (PAAO) layer with fewer cracks on a tubular substrate is quite challenging. The PAAO layer on a curved surface grows slower than that on a flat surface and is susceptible to cracking. This study aims to improve the crack resistance of the PAAO layer grown on a tubular aluminum substrate by adding ethylene glycol (EG). Each bath contained additive concentrations of 0, 5, 10, and 15 vol% EG. Anodization proceeded for 4 h at a temperature of 10 ℃ using the potentiostatic mode at 25 V in a sulfuric acid bath and 40 V in an oxalic acid bath. The crack and pore structure were investigated using a field emission scanning electron microscope (FE-SEM). The kinetic curve and FE-SEM investigation indicated that the addition of EG in the bath slowed the growth rate of the PAAO layer in both anodization baths. The lower oxidation rate drastically improved the crack resistance, as revealed by the significant reduction in the crack population and narrower crack width. The additive EG presumably enhanced the electrolyte viscosity and reduced the heating effect released during oxide growth. Consequently, the layer thickness and pore size decreased with the increase in the EG concentration.
Co-Authors Asoh, Hidetaka Hernandi, Rafli Ihsan Izzat, Rayhan Juwono, Ariadne Laksmidevi Manogari Sianturi Ono, Sachiko Pragitta, Riene Kaelamanda