One of the main problems encountered by curators and conservators in charge of metallic collections from Historical Heritage is related to their long-term conservation, since metallic artifacts undergo corrosion phenomena, which are the result of the interaction between the metal and its environment. The use of rust converters and microcrystalline waxes can be an ecological alternative to the traditional and more aggressive conservation techniques. Although the mechanism of action of these compounds is not clear, it is assumed that they react with iron oxides and generate new compounds that may have a passivation effect on the metallic surface. This paper proposes to show how simple electrochemical techniques can be used as an efficient tool to contribute to the diagnosis of the conservation state of cannon balls and to monitor the restoration treatment. The objective of the present work is to evaluate the effectiveness of a rust converter based on tannins and phosphoric acid, and one microcrystalline wax applied on cannon balls samples exposed to a marine atmosphere. The protection properties of the oxide or conversion layer are evaluated by electrochemical impedance spectroscopy (EIS) technique. The results obtained suggest that the use of the rust converter and microcrystalline wax protects the cannon balls, even though its effect is less evident when the deterioration degree is larger.

The Bastion of San Pedro is part of the defensive infrastructure projected by Spanish colonizers in San Francisco de Campeche City, in order to protect the city and their inhabitants from pirates who ravaged the region during the XVIth and XIXth centuries. The bastion is a masonry structure built by using calcareous materials according the Spanish procedures from the edge. Since its construction, it has been under the synergetic interaction of natural and anthropogenic factors that promote degradation. In this study optical microscopy (MO) and scanning electron microscopy coupled to a dispersive analysis system (SEM/EDS) were used in order to analyze the stratigraphic profile of mortar weathered samples collected from walls of the Bastion of San Pedro. According the results, the samples were formed by three substrata: an upper external layer in contact with the environment (100 to 300 µm), the other one is an inner layer with thickness around 100 to 400 µm. The last substrate was formed by the mortar matrix composed by elements such as C, O, Ca, Si and Al, that indicate their mineral origin. By the other hand, it is important to note that the upper layer contained higher proportion of C respect to the other layers. It is probably major consequence of biomass encrustation rather that atmospheric pollution according to the particular environmental conditions surrounding the building.

Chemical and biological deterioration of surfaces of historic constructions is one of the main causes of destruction of cultural heritage buildings. Effective techniques are searched in order to control the biofilm development of cultural heritage without damaging the environment. Nanotechnology is an emerging option with several applications, including those for improving stability and corrosion resistance in surfaces. Production of nanomaterials from organic nature or green synthesis offers ecological advantages such as low environmental impact. This paper proposes the use of silver nanoparticles of biological synthesis as an alternative for control of microorganisms that cause biodeterioration. The present study highlights the effect of these nanoparticles in the inhibition of bacterial growth. These particles were produced by biological synthesis with Tecoma stans L. extracts. Their characterization included analysis UV / Vis spectroscopy, scanning electron microscopy (SEM) and particle size distribution.

Recent discoveries have shown the presence of several shipwrecks and historical pieces submerged in the seacoast of the Yucatan Peninsula of Mexico. Within these remains, it is common to found objects manufactured in copper alloys that were part of the construction system of the vessel. For the present study, different surface analysis techniques were applied to tubular copper alloy objects collected in the wreck “El Tejas”. The metallographic study allowed us to know not only the microstructure but also features over its manufacturing technique, as an example of nineteenth-century handmade production. SEM, EDX and XRF techniques allowed us know the elemental composition and establish the mechanisms of degradation of the different copper alloys in the seabed and evaluated a preservation method that consist on removing chlorine compounds by cleaning with pressure steam of distilled water.

Five historical full-size wood structural beams of Picea abies were tested with ultrasound. The speed of ultrasound, the modulus of elasticity, the moisture content and the wood density were measured for each specimen. The speed of the ultrasound waves in the radial, tangential and longitudinal directions was 1,769 m/s, 1,599 and 5,713 m/s respectively. The modulus of elasticity in the radial, tangential and longitudinal directions was 1,353 MPa, 1,069 MPa and 13,863 MPa respectively. The moisture content was on average 11.92% and the density was on average 422 kg/m3. Wood parameters such as density and orthotropic directions had influence in ultrasound measurements. In spite of local weakness in the beams, they had enough strength to be considered full structural members.

The historical monuments such as cathedrals, public buildings and so on, are a fundamental part of artistic heritage of a country. They reflect, ultimately, much of its culture and history. For several decades, their aspect has been seriously changed by graffiti, which clearly endangers their preservation state and causes loss of their esthetic appearance and historic value. This damages seriously the self-esteem of residents who witness the continued and strong degradation of their cultural heritage. The aim of this work is to study the removal of graffiti from a characteristic stone which is used in Morelia (México) as the raw material for architectural monuments, using a high power diode laser treatment. We concluded that continuous wave regime leads to better results than modulated wave regime; additionally, a two laser passes process demonstrated a high performance.