guilminot e. electrolytic treatment in situ conserv. marine artefacts. 2010

8/7/2019 Guilminot E. Electrolytic Treatment in Situ Conserv. Marine Artefacts. 2010

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1/32 Leiden, January 2010

REMOTE MONITORING OF ELECTROLYTIC

TREATMENT: APPLICATION FOR THECONSERVATION OF MARINE ARTEFACTS

Elodie Guilminot

© DRASSM

© DRASSM

© DRASSM



Electrolysis of marine artifacts

Marine artifacts need

a dechlorination

Background Information

Destructive effect

of chlorides


Immersion

in alkaline solutions

Cathodic

polarisation

Advantages:

Facility to remove concretions

Preservation of the original surface

Difficulties:

Good electric contacts

Control of electrochemical parameters

© Arc’Antique




Background Information: Main parameters


Solution : 2% KOH or NaOH

Removal of concretions

Object’s Potential : -1.6V/ESS

Actions:

Bubbles of H2 on metallic surface

Extraction of chlorides

Embrittlement of concretions

AND

Dechlorination

Others (I or U) depend on the size of object

Monitoring:

Object’s potential

Concentration of chlorides

Risks:

Cracking of the object

Corrosion of the anode

Mechanical

action to remove

concretions





Solution : 1% KOH or NaOH

Dechlorination by

cathodic polarization


Actions:

No bubbles of H2

Extraction of chlorides

Dechlorination


Monitoring:


Concentration of chlorides

Risks:

Cracking of the object

Corrosion of the anode

Change of baths






Solution : distilled water

Rinsing under

polarization


Actions:

Protection of iron Extraction of KOH or NaOH


Monitoring:


Conductivity of the solution

Risks:

Corrosion of the object

Ohmic drop





In practice: Electric connections


Small objects Large objects

With agrinder tool

With a

drill

To verify the quality

of contacts

© Arc’Antique

© Arc’Antique

© Arc’Antique




In practice: Electric connections



To verify the

quality of contacts

With a

screw

clamp

With a

spring

© Arc’Antique

© Arc’Antique

© Arc’Antique

© Arc’Antique © Arc’Antique




In practice: Conception of the anode



Constructionof the anode

Blocks

© Arc’Antique

© Arc’Antique

© Arc’Antique

© Arc’Antique




In practice: Polarization and monitoring


© Arc’Antique

© Arc’Antique

© Arc’Antique




In practice: Interventions of the specialists


To remove the concretions

With a chisel

© Arc’Antique

© Arc’Antique

© Arc’Antique© Arc’Antique






To remove the concretions

With a drilling machine

Discovery of

cannonball, hemp cord

and gunpowder

© Arc’Antique

© Arc’Antique

© Arc’Antique






To change the solution

To turn over the objects

To fill the tank

© Arc’Antique

© Arc’Antique






Final restoration

Application of a protection

Cleaning with a sandblaster Application of the wax

© Arc’Antique

© Arc’Antique




Treatment Times


Size of objectsSmall objects Large objects

A few months to 1 year 3 to 6 years for a cast iron cannon ∼∼∼∼ 15 days of manual intervention for a 3 year treatment

Now 16 cannons and 2 anchor are treated

No more room in Arc’Antique

Waiting period for

new objects too long

© Arc’Antique



Remote monitoring of Electrolytic treatment


First delocalized treatments


Increasing interest in marine cultural heritage

Since 2005, development of an electrolytic system by remote monitoring

Delocalized Treatments

Possibility to promote these cultural heritage

Whishes of local authorities and museums to treat objects on site

So long waiting time to treat the new marine artefacts

Large objects

1997: Mayotte 1999: Biscarosse 2002: Saint Brieuc

The success of the treatment depends on local people

Sometimes, the treatment was finished in Arc’Antique





First delocalized treatments


Increasing interest in marine cultural heritage

Since 2005, development of an electrolytic system by remote monitoring

Delocalized Treatments

Possibility to promote these cultural heritage

Whishes of local authorities and museums to treat objects on site

So long waiting time to treat the new marine artefacts

Large objects

1997: Mayotte 1999: Biscarosse 2002: Saint Brieuc

The success of the treatment depends on local people

Sometimes, the treatment was finished in Arc’Antique





The project

Site of the treatment

Arc’Antique laboratory

Measurement of main parameters by

treatment system

Communication by internet or network

Monitoring and control in Arc’Antique

Remote PC





The first prototype

Serveur Arc’Antique

Programmable

stabilized

generatorPC card with

Windows XP

Acquisition system

The first prototype with commercial components

Modem

Faraway PC

Program under Labview

for Windows XP

Monitor

screen

Several access levels

0: Public1: local authorities

2: Arc’Antique





The Saint Malo Project: First Tests Cannons from Natière 1 (Saint-Malo, France)

Frigate

“La Dauphine”

XVIIIth

century

9 cast iron

cannons

Treatment on site since March 2006

but not too far from Arc’Antique laboratory

© DRASSM

© DRASSM





The Saint Malo Project: First TestsTreatments on site

Cathodic Polarization

in KOH

usual devices(with 2 electrodes):

5 and 2 cannons

Comparison

between usual andnew electrolytic

device

Treatment in 3 tanks :

2 usual devices and the new electrolytic system by remote monitoring

Prototype by

remote monitoring(with 3 electrodes):2 cannons

© Arc’Antique





The Saint Malo Project: First Tests

Control system on site

Training a local

operator to stir thesolution and take

samples of the solution

With this prototype

Potentiostatic

control in real timeMeasurement of the

potential value, the

current and the cell

voltage every second

Monitoring of thetreatment in

Arc’Antique

© Arc’Antique





The Saint Malo Project: First ResultsComparison between a usual device and the prototype by remote control

usual device

1 week to regulate the potential

3 years - 8 baths - 14,8kg of Cl

Potentiostatic control in real time accelerates the regulation

Prototype by remote control

33 hours to regulate the potential

3 years - 8 baths - 17,6kg of Cl>>

The treatment by remote control extracts chlorides faster

[Cl-]by remote control

= 2× [Cl-]classical





Limits of this first PrototypeTechnical problems

Power cuts, connection problems (low flow)

Defaults of communication

To avoid the use of Windows….

Problems with the reference electrode

SSE 2 months of life in alkaline solutions (SSE=0,6V/NHE)

Use of a metallic electrode (in W) but need for reference data

Hg/HgO adapted electrode in KOH (Hg/HgO=0,1V/NHE)To protect a commercial electrode with an extension

Instability to regulate the potential

Different objects (1 anchor and 2 cannons)

For the high power

To modify the program

Improvements Second system with industrial elements





The new system: Kraken

Conception

More reliable, more compact, more robust lighter system

Easily transportable box

Electronic

integrated card

Different connections: intranet or modem (phone line, wifi, adsl, GSM, GPRS)

Project since 2008 - Financial support by Oseo

© A3IP

© A3IP





The new system: KrakenCharacteristics

Equivalent with a numeric potentiostat adapted to the conservation treatment

Conditions of the use: -20/+55°C and <90%RH

Current range: 0-20A or 0-2A (precision: 10-1mA)

Cell voltage range: 0-20V or 0-20V

Power range: 0-150Watts or 0-40Watts

Precision of the potential object: about 1mV (Range potential: -5V/5V)

Possibility to connect 2 reference electrodes

Electric net: 110 or 120V / 50 or 60Hz (automatic detection)

Control and monitoring directly on the system or remote with web page

Possibility to stir the solution and to fill the tank automatically

Battery: Range of 30min to 1hour





The new system: KrakenThe software





The new system: KrakenIn practice

Tests in Arc’Antique

Use in Saint Malo: Rinse of 5 cannons

Use in Batz Isle: Treatment of 2 cannons

Dechlorination

Maximum power: Rinse

© Arc’Antique

© Arc’Antique





The new system: Kraken

Current developments

Development of the sensors to fill the tank

Improvement of the software:- Curves of measurements

- Management of several systems

Validation of European standard (CE)

Conclusions

Adapted tool to control and monitor the electrolytic treatment

Adapted tool to promote the cultural heritage for museums or local authoritiesPossible tool to teach electrochemical techniques to other laboratories

We can test this system during the experiment session

guilminot e. electrolytic treatment in situ conserv. marine artefacts. 2010

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