The Borobudur Conservation Center in Magelang, Central Java, Indonesia has received underwater cannonballs from a shipwreck in the sea near Batavia, Jakarta, Indonesia. This artifact is a shipment from the Directorate for the Preservation of Cultural Heritage and the Indonesian Ministry of Education and Culture. This study aims to conserve the underwater cannonball before it is stored in a museum. The removal of the protective crust of iron artifacts without the correct and proper method can cause rapid corrosion. To prevent damage, artifacts must be conserved in the right solution. This research aims to stop the process of corrosion and conserve iron objects in aqueous alkali solutions, and the potential corrosion was measured. Conservation was conducted in four stages during this research project. The first stage is the identification of weathering, and the second stage is the analysis and characterization of the corroded surface using a microscope, XRD (X-ray diffraction), XRF (X-ray fluorescence), and SEM (scanning electron microscopy). The third stage is the passivation/deactivation process, which was achieved using sodium hydroxide, soapy water and kaffir lime water. The fourth stage is stabilizing/coating the iron cannonball underwater heritage materials as soon as possible using microcrystalline wax to prevent further corrosion, so this stage should solve the conservation problems associated with the object so that the objects can last for a long time. Dry and wet activated corrosion was characterized by applying XRD to the obtained mineral akageneite. The akageneite minerals were actively corroded and contained high concentrations of Cl atoms revealing dry and wet activated corrosion of 66.603% and 64.963%, respectively. After being conserved with several steps and NaOH, soapy water and kaffir lime water, inactive corrosion was observed. Based on the results of the analysis performed with XRF, the cannonball does not contain Cl, and the Fe content is 98.99%. The conservation method used in this research is excellent and appropriate to conserve cultural heritage materials, including underwater iron cannonballs.

This study aims to conserve the underwater cannonball before storing it in a museum. Removing the protective crust of iron artifacts without the correct and proper method can cause rapid corrosion. To prevent damage, artifacts must be conserved in the right solution. Conservation was conducted in four stages during this research project. The first stage is the identification of weathering, and the second stage is the analysis and characterization of the corroded surface using a microscope, XRD (X-ray diffraction), XRF (X-ray fluorescence), and SEM (scanning electron microscopy). The third stage is the passivation/deactivation process, achieved using sodium hydroxide, soapy water and kaffir lime water. The fourth stage is stabilizing/coating the iron cannonball underwater heritage materials as soon as possible using microcrystalline wax to prevent further corrosion. This stage should solve the conservation problems associated with the object so that the object can last for a long time. Dry and wet-activated corrosion was characterized by applying XRD to the obtained mineral akageneite. The akageneite minerals were actively corroded and contained high concentrations of Cl atoms revealing dry and wet activated corrosion of 66.60% and 64.96%, respectively. After being conserved with several steps and NaOH, soapy water and kaffir lime water, inactive corrosion was observed. Based on the results of the analysis performed with XRF, the cannonball does not contain Cl, and the Fe content is 98.99%. The conservation method used in this research is excellent and appropriate for conserving cultural heritage materials, including underwater iron cannonballs.

Borobudur Conservation Center Magelang, Central Java Indonesia, has received underwater cannonball heritage in the shipwreck from the sea Batavia Jakarta Indonesia. This heritage is a shipment from the Directorate for the Preservation of Cultural Heritage and the Destruction of the Indonesian Ministry of Education and Culture. This study aims to the conservation of underwater cannonball before being stored in a museum. Removal of the protective cover crust of iron artifacts without the correct and proper method can cause the more quickly the process of corrosion. To prevent this more damaging, the conservation of artifacts in the right solution is necessary. This research aims to stop the process of corrosion and conserve objects of iron in aqueous alkali corrosion potential measurement through there. Conservation of this research was conduct in four stages. The first stage is the identification of weathering, and the second stage is the analysis and characterization of surface corrosion object using the handy microscope, XRD (x-ray Diffraction), XRF (x-ray Fluorescence), and SEM (Scanning Electron Microscopy). The third stage is the passivation/deactivation process of corrosion using sodium hydroxide, soap water and kaffir lime water. The fourth stage is stabilization/coating of materials iron cannonball underwater heritage as soon as possible using microcrystalline wax so as not further corrosion process going so that this stage should be able to complete the conservation problems of the object until they can last for the long term. Characterization of dry and wet activated corrosion using XRD obtained mineral akaganeite. Akaganeite minerals showed active corrosion containing high concentrations of Cl atoms for dry and wet activated corrosion 66.603% and 64.963%, respectively. After being conserved with several steps and using NaOH, soap water and kaffir lime water show inactive corrosion. Based on the results of analysis with XRF cannonball does not contain Cl and Fe content reaches 98.99%. The conservation method used in this research is excellent and appropriate to conserve the objects of cultural heritage cannonball material underwater iron heritage.