Ekstrak ubi ungu dikembangkan sebagai inhibitor organik untuk mengurangi laju korosi pada baja karbon rendah di lingkungan NaCl 3,5%. Penelitian telah dilakukan dengan perbedaan waktu perendaman (3,6,9,dan 12 hari) menggunakan metode kehilangan berat. Konsentrasi inhibitor ekstrak ubi ungu yang digunakan pada semua waktu perendaman sebesar 6 ml. Ekstrak ubi ungu memiliki zat antosianin yang berfungsi sebagai antioksidan untuk menghambat laju korosi. Ekstrak ubi ungu kurang efektif sebagai inhibitor organik pada lingkungan NaCl 3,5% dengan efisiensi 37,63%-43,42% selama waktu uji 3-12 hari dengan efisiensi maksimum pada waktu perendaman 9 hari.

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Purple sweet potato extract was developed as an organic inhibitor to reduce the rate of corrosion in low carbon steel in NaCl 3.5% environment. Research has been conducted with different immersion time (3,6,9, and 12 days) using weight loss methode. Concentration of inhibitor purple sweet potato as much as 6 ml for all immersion time. Purple sweet potato extract is a substance that anthocyanins act as antioxidants to inhibit the rate of corrosion. Purple sweet potato extract is less effective as an organic inhibitor in NaCl 3.5% environment with efficiency of 37.63%-43.42% during the test period 3-12 days with maximum efficiency in 9 days.