Studi Komparatif Degradasi Fisik-Kimia pada Enamel Coating 150 Micron Akibat Paparan Uap dan Perendaman Asam Sulfat

Riswan, Hendri (2026) Studi Komparatif Degradasi Fisik-Kimia pada Enamel Coating 150 Micron Akibat Paparan Uap dan Perendaman Asam Sulfat. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Korosi titik embun asam sulfat (H2SO4) pada komponen cold-end Air Preheater (APH) menurunkan keandalan pemanas udara di pembangkit listrik. Penelitian ini bertujuan menganalisis ketahanan kimia, kinetika kehilangan massa (weight loss), laju korosi (ASTM G31), dan mekanisme degradasi enamel coating nominal 150 µm pada baja JIS G3133 SPP. Karakterisasi awal fasa oksida enamel unexposed diuji menggunakan X-Ray Fluorescence (XRF), sedangkan simulasi korosi dilakukan melalui uji uap furnace (140°C, 1,7 mol/L H2SO4, 25 jam) dan uji perendaman akselerasi (1,9 mol/L; 5,6 mol/L; 9,4 mol/L, 60°C & $80°C, 24 jam). Hasil XRF menunjukkan enamel unexposed didominasi SiO2 (90,05% wt), dengan keberadaan oksida reaktif Fe2O3 (4,23% wt), Al2O3 (2,12% wt), dan K2O (1,23% wt). Pada uji uap furnace, enamel 150 µm menekan weight loss rata-rata hingga 64,29% (0,00033 g) dan menekan laju korosi dari 0,926 mm/year (baja polos) menjadi 0,104 mm/year (efisiensi 88,77%). Pada uji perendaman, konsentrasi 9,4 mol/L memicu pasivasi (0,23–0,42 mm/year), konsentrasi 5,6 mol/L menunjukkan leaching terkontrol (17,46–25,48 mm/year), sedangkan konsentrasi 1,9 mol/L pada 80°C mengalami kegagalan struktural akibat retak hidrasi (197,26 mm/year). Analisis SEM-EDS dan XRF mengonfirmasi bahwa pelarutan selektif oksida reaktif memicu pembentukan rongga mikro (microvoids) sebagai situs inisiasi retak, di mana ketebalan pelapis berperan membatasi perambatan retak (crack propagation) menuju substrat baja
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Sulfuric acid (H2SO4) dew-point corrosion on cold-end Air Preheater (APH) components impairs power plant reliability. This study investigates the chemical resistance, weight loss kinetics, corrosion rate (ASTM G31), and degradation mechanisms of nominal 150 µm porcelain enamel coatings on JIS G3133 SPP steel. Initial oxide compositions of unexposed enamel were determined via X-Ray Fluorescence (XRF), followed by corrosion simulations in a Horizontal Tube Furnace (140°C, 1,7 mol/L H2SO4, 25 hours) and accelerated immersion tests (1,9 mol/L; 5,6 mol/L; 9,4 mol/L, 60°C & $80°C, 24 hours). XRF analysis revealed that unexposed enamel is dominated by SiO2 (90,05% wt), alongside reactive oxides including Fe2O3 (4,23% wt), Al2O3 (2,12% wt), dan K2O (1,23% wt). Under furnace vapor testing, the 150 µm coating reduced average weight loss by 64,29% (0,00033 g) and suppressed the corrosion rate from 0,926 mm/year (bare steel) to 0,104 mm/year (88.77 efficiency). During immersion, 9,4 mol/L H2SO4 induced passivation (0,23–0,42 mm/year), 5,6 mol/L exhibited controlled leaching (17,46–25,48 mm/year), whereas 1,9 mol/L at 80°C caused structural breakdown via hydration stress cracking (197,26 mm/year). SEM-EDS and XRF analyses confirmed that selective acid leaching of reactive oxides generates microvoids as crack initiation sites, where coating thickness restricts crack propagation toward the underlying steel substrate

Item Type:	Thesis (Masters)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA462 Metal Corrosion and protection against corrosion T Technology > TA Engineering (General). Civil engineering (General) > TA491 Metal coating.
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User:	Hendri Riswan
Date Deposited:	04 Aug 2026 08:12
Last Modified:	04 Aug 2026 08:12
URI:	http://repository.its.ac.id/id/eprint/143577

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