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All Journal Makara Journal of Science Indonesian Journal of Aerospace
Juwono, Ariadne Laksmidevi
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Aerospace Engineering Astronomy

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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

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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.
Mass Optimization of Rocket Nozzles Using Ablative Materials: A Case Study on Indonesian Sounding Rockets Abrizal, Haryadi; Juwono, Ariadne Laksmidevi; Jihad, Bagus Hayatul
Indonesian Journal of Aerospace Vol. 23 No. 1 (2025): Indonesian Journal Of Aerospace
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/ijoa.2025.11394

Abstract

This study presents a comprehensive redesign of the RX450 sounding rocket nozzleaimed at reducing mass while maintaining thermal and structural integrity. The baselinedesign, characterized by heavy steel casing and monolithic graphite liners, imposes significantlimitations on payload capacity and flight performance due to its weight and thermalmanagement challenges. The proposed design replaces the divergent section’s steel casingwith a combination of ablative silica-phenolic composite liners and aluminum 6061 structuralsupport, achieving a substantial mass reduction from approximately 59 kg to 14.5 kgin this critical region. Thermal simulations demonstrate that the addition of a glass-phenolicinsulation layer effectively limits heat transfer to the metallic casing, allowing for thinnerstructural components without compromising safety. Structural analyses confirm thatboth steel and aluminum sections maintain high safety factors under operational loads.Comparative evaluations of alternative configurations further highlight the benefits of advancedcomposite materials and innovative structural concepts, with the lightest modelreducing total nozzle mass by around 40% compared to the baseline. While these resultsare based on literature-derived properties and simplified assumptions, they underscore thepotential of integrating ablative composites and lightweight metals to enhance rocket nozzleperformance. Future work will focus on detailed thermochemical modeling, experimentalvalidation, and full-scale testing to confirm thermal-structural behavior and erosionrates. Overall, this study supports Indonesia’s strategic objective of advancing indigenousrocket technology through accessible, high-performance materials and design innovations.
Co-Authors Abrizal, Haryadi Anawati, Anawati Jihad, Bagus Hayatul Manogari Sianturi