Undetermined - Fe Alloy - Early medieval times

Undetermined - Fe Alloy - Early medieval times

Undetermined

Moreau. Caroline (Laboratoire MATERIA VIVA, Toulouse, Midi-Pyrénées, France) & TOUZEAU. Julie (Laboratoire MATERIA VIVA, Toulouse, Midi-Pyrénées, France)

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Credit Materia Viva, C.Moreau.

Fig. 1: Artefact (component of a furniture?) with soil and corrosion products (side view),

Credit Materia Viva, C.Moreau.

Fig. 2: Lateral view of the object,

Credit Materia Viva, C.Moreau.

Fig. 3: Artefact after restoration, the blue square indicates the detail of Fig.4,

Credit Materia Viva, C.Moreau.

Fig. 4: Detail of the cleaned surface showing shiny grey/blue surface and red/brown spots,

Metal piece probably coming from a wooden box forming a "L" shape, coverered with iron corrosion products. Dimensions: L around 10cm and W around 5cm.

Furniture element

Las Cravieros, Fanjeaux, France

2022

Early medieval times

Soil

Las Cravieros, Fanjeaux (Favennec Benoît), Languedoc-Roussillon

None

FS665 US10011

Mechanical removal of the corrosion products and protection with resin paraloid B72 in acetone.

Complementary information

The artefact might have been exposed to high temperatures because it was found around a forging work area.

Credit Materia Viva, C.Moreau.

Fig. 5: The blue square indicates the location of the analysed area by binocular observation,

The schematic representation below gives an overview of the corrosion structure(s) encountered on the object from a first visual macroscopic observation. 

 

S1 Sediment powdery and non adherent
CP1 Corrosion product bright orange corrosion product or soil orange-coloured by corrosion products
CP2 Corrosion product brown layer of corrosion products with silica grains
CP3 Corrosion product very thin discontinuous layer of a red corrosion product without silica grains
CP4 Corrosion product grey/blue continuous layer
SV1 Structural void  
M1 Metal compact metal. Observation of stretched metal around the structural voids


Table 1: Description of the principal characteristics of the strata as observed under binocular and described according to Bertholon's method.

Credit Materia Viva, C.Moreau.

Fig. 6: Stratigraphic representation of the corrosion structure of the object by macroscopic and binocular observation with indication of the corrosion structure used to build the MiCorr stratigraphy of Fig. 7 (blue rectangle),

Fig. 7: Stratigraphic representation of the corrosion structure of the object observed macroscopically under binocular microscope using the MiCorr application with reference to Fig. 6. The characteristics of the strata are only accessible by clicking on the drawing that redirects you to the search tool by stratigraphy representation, credit Materia Viva, C.Moreau.

None.

Fe Alloy

None

None

None

none

Complementary information

None.

None.

None.

The presence of only iron corrosion products allows us to propose an iron base metal.

None

Fe

Complementary information

None.

Corrosion products are typical of those of iron-based alloys.

None

None

Complementary information

None.

None.

This ferrous alloy object that may have belonged to a wooden box was found near a forge area. Among the observed corrosion strata and characteristic of the corrosion process of ferrous metals, two corrosion layers CP3 and CP4 appear atypical compared to other corrosion profiles of similar metals (cf MiCorr | Knife with a groove on both sides DEV 995/814 PR - Fe Alloy - Early medieval times - Switzerland). They could be related to high temperature exposure due to the proximity of a forging zone.

The limit of the original surface is probably between CP2/CP3 and CP3/CP4. Layer CP3 (in red) shows no more silica grain coming from the burial environnement. CP3 can be removed, but this will eliminate certain elements relating to the history of the artefact.

References on object and sample

1. Raffel, P., (2004) Etudes sur la corrosion-conservation de fers archéologiques incinérés, sous la dir. de Monique Drieux et Francis Dabosi, internship report DESS, Toulouse, Université Paul Sabatier.

2. Knife with a groove on both sides DEV 995/814 PR