"
ABSTRAKPenelitian ini dilakukan untuk menganalisa pengaruh inhibisi ekstrak cair daun
Beluntas (Pluchea Indica Less.) terhadap korosi pada baja karbon rendah di
lingkungan 3,5% NaCl. Penelitian dilakukan menggunakan pengujian weight loss,
polarisasi, dan Fourier transform infrared spectroscopy (FTIR). Pengujian weight
loss menunjukkan bahwa perendaman selama 9 hari dengan penambahan ekstrak
sebanyak 3 mL memberikan nilai rata-rata efisiensi paling maksimum sebesar
75,97% dengan rata-rata laju korosi paling minimum sebesar 0,89 mpy. Pengujian
polarisasi menunjukkan terjadi pergeseran kurva ke arah anodik pada penambahan
ekstrak sebanyak 1,2,3 mL, dan bergeser ke arah katodik pada penambahan
sebanyak 4 mL. Penambahan ekstrak berpengaruh terhadap penurunan laju korosi
yaitu dari 24,8 µA.cm-2 menjadi 5,04 µA.cm-2
, sehingga memperkuat hasil
pengujian weight loss bahwa ekstrak daun Beluntas dapat menghambat korosi
baja karbon rendah di larutan 3,5% NaCl. Pengujian polarisasi menunjukkan
bahwa ekstrak daun Beluntas memiliki tipe inhibisi campuran (mixed) dengan
kecenderungan lebih dominan kearah anodik berdasarkan nilai potensial korosi
yang berubah secara acak. Pengujian FTIR menunjukkan bahwa estrak daun
Beluntas teradsorpsi pada permukaan baja karbon rendah dan proses adsorpsinya
terjadi melalui gugus fungsi yang dimiliki ekstrak. Mekanisme adsorpsi ekstrak
daun Beluntas sesuai dengan Langmuir adsorption isotherm yang menunjukkan
bahwa telah terjadi pembentukan lapisan monolayer di permukaan baja karbon
rendah.
ABSTRACTThe study was conducted to analyze the inhibition effect of Beluntas (Pluchea
indica Less.) leaves extract on the corrosion of low carbon steel in 3.5% NaCl
environment. The study was invetigated by weight loss, polarization, and Fourier
transform infrared spectroscopy (FTIR) methods. Weight loss showed that soaking
for 9 days with the addition of 3 mL of the extract gave an average value of the
maximum efficiency of 75.97% with an average of the minimum corrosion rate of
0.89 mpy. Polarization shows the polarization curve shifts to the anodic direction
in addition of 1,2,3 mL extract, and shifted toward the cathodic curve to the
addition of 4 mL. The presence of inhibitor causes decrease in the corrosion rate
from 24.8 to 5.04 μA.cm-2, thus confirm the results of weight loss that Beluntas
leaves extract can inhibit the corrosion of low carbon steel in 3.5% NaCl solution .
The polarization showed that the Beluntas leaves extract acts through mixed mode
of inhibition, as evident from the values of Ecorr, which do not increase or decrease
in a regular manner from the blank value. FTIR showed that the Beluntas leaves
extract adsorbed on the surface of low carbon steel and the process of adsorption
occurs through a functional group extract. Beluntas leaves extract shows
Langmuir adsorptions isotherm that indicated the monolayer formation on the low
carbon steel surface."
