A unique Corrosion Mapping Microscope
  and Profilometer from CMC Ltd

CorMap is a computer-controlled scanning corrosion microscope
the principle of a scanning reference electrode. An electrochemical probe
(typically 100
m m diameter) is automatically scanned across the specimen,
producing a corrosion sites map. Both potential and current maps are
produced. BOTH vertical and horizontal components of potential and current
are collected, unlike the SVET instrument which gives only the vertical current,
and no potential data. The unit assesses unpainted alloy or painted metal
performance in specific environments.
Monitors performance of ferrous and non-ferrous metals, homogeneous and
heterogeneous alloys, composites with metallic phases, cermets.
Suitable for research and for materials selection for the following industries:
oil, process, chemical, water treatment, paint and other coatings, construction
and marine.

A unique feature
is an automatic height sensor ensuring proximity while
allowing a non-flat surface to be scanned (e.g. a weld bead). This feature
also eliminates any need for leveling the specimen before scanning and gives
ease of use - results are not operator-dependent.
The instrument is computer-controlled and high resolution corrosion data
from a specified precise area of a specimen immersed in an electrolyte is

A real-time two-dimensional coloured electrochemical potential plot is produced on the monitor screen during the scan, to follow progress.

Profilometer mode: A simultaneous (or separate) profile scan can be performed.

Scan area: Up to 40x40 mm. The (operator selectable) x or y movement is 1.25 microns minimum and the maximum is 40 mm. A larger scan area can be provided on request (please enquire about additional costs). Step resolution is 1.25 microns (enquire for smaller resolutions).

Multiple scans: Up to 9 scans can be performed fully automatically at different operator-preset times, on the same precise specimen location. The probe is automatically held away from the scanned zone during any waiting periods.
The data is automatically logged into the computer.

The scanning reference electrode corrosion microscope is versatile and easy-to- use. The electrode arrangement used is highly sensitive and also gives high resolution, as seen from example pictures supplied on a CD. The background noise level is well below 1 microvolt (see examples on CD). 

The unit can be used alongside a factory production line for paint quality control, as well as in the laboratory.

There are two modes of use:

Flatscan: this is the classic mode, successfully used for level specimens. It is faster than the fully automatic mode (described below) as there is no time taken in adjusting the probe height. The scan height can be pre-set.
A one-thousand-point scan of a 4 mm by 2 mm area takes less than 20 minutes.

Automatic mode: this is fully automatic and once started, the system runs without any attention being needed. This mode has a sensitive sensor, which lifts the probe up and down over a weld or a paint blister, while taking readings.

Operation: Precision micrometer-driven baseplate with specimen tray for electrolyte (e.g. NaCl solution), controlled by PC computer to any ordinate on the x,y,z axes. x, y, z coordinates are listed on the screen along with the corrosion map in real-time during the run. Scan steps can be pre-set to any size down to 1.25 microns (enquire for smaller resolutions).

Graphics output:

Several data file formats are automatically and simultaneously produced, giving a choice of plotting programmes for the user.
Data files (in ASCII) in formats which
can be plotted using: 

q   Axum, or any commercial plotting programme (Axum programme not supplied, available from Trimetrix)
Excel (Excel programme not supplied - routinely available from Microsoft)
CMC Advanced Graphics programme (2D and 3D) (this programme is supplied)
(example output is shown in other pages of this website): 
Colour 2D plots allow the cursor to be moved anywhere to display the x,y and mV values for any data-point on the screen at the cursor's position.
q  Colour 3D plots, and combined coloured 2D and 3D on the same plot can be obtained. 
q 3D plots can be rotated, and also tipped, (in one-degree steps) in real-time, to give unobstructed 3D views.

All of these plot formats are also supplied for the CURRENT mode and the PROFILOMETER mode output

Advantages of CorMap over SVET vibrating electrode equipment :

(1) The equipment has a fully automatic height-adjusting probe, contouring over non-flat specimens and thus requires no pre-run levelling. Thus results are not operator-dependent.
(2) The probe tip is only about 3 microns from the specimen
(3) There is no probe vibration and so no stirring away of fine peak detail. SVET peaks seem slightly fuzzy, with less fine detail, and shorter peaks than from a non-vibrating scanner, which may be due to stirring by the vibrating tip. The effect of the vibration of a SVET probe tip has been demonstrated by Worsley, Williams & McMurray (Scanning probe techniques in corrosion research, Conf. Jan 2004, Sheffield Hallam University, UK).
(4) Jitter occurs on SVET electromechanical vibrators, which means antinodal positions are not precisely the same on successive oscillations, causing spurious signal variations.
(5) The electrode design is quite different from other early manufactured versions of the non-vibrating electrode (which have been discontinued by their manufacturers due to lack of sensitivity), and it has much higher sensitivity. Other electrodes can also be used in the electrode holder, including custom designed electrodes.
(6) If a SVET electrode touches the specimen surface, it is destroyed, but a CorMap electrode is not damaged.
In the unlikely event of a component failure, all our CorMap components are industry-standard items which can be locally obtained and fitted by a technician, which is an attractive/reassuring feature for buyers: No special replacement parts are required from CMC (such as SVET vibrating electrodes). Even the CorMap electrodes can be repaired or made by a competent glassblower.

CorMap Package:
q   Precision micrometer-driven moving horizontal baseplate with specimen tray for electrolyte (e.g. NaCl solution), controlled by PC computer to any ordinate on the x,y,z axes.
x, y, z coordinates are listed on the screen along with the corrosion map in real-time during the run.
Scan steps can be pre-set to any size down to 1.25 microns (enquire for smaller resolutions).
Standard scanned area can be up to 40x40 mm (equipment for larger areas can be supplied, please enquire cost).
An automatic sensing device to enable close and fixed proximity of the reference electrode to the sample.
Sensitive micro-reference electrode for high-resolution potential mapping.
Current mapping.
Profilometer mode.
Software to allow positioning of scanning probe as well as capability for fine and coarse scanning.
Fully automatic scanning over non-flat surfaces such as weld beads.

q Manual.
Please enquire:

(Note: CMC reserves the right to change prices without notice, unless specifically quoted).

Payment structure:
To be negotiated, depending on location of buyer.
Goods are ready for despatch 4-6 weeks from placement of order.

CMC Ltd is a long standing company (established 1987). We pride ourselves on the excellent support and services we give to our clients.

Terms and conditions:

The hardware and software are guaranteed for one year. No guarantee is given for misuse or for spillages, or for moving parts due to excessive wear due to over-weight objects being placed on the moving tray (maximum weights will be specified).

After the guarantee period, the unit is designed to allow the user to repair the unit locally, as construction is modular and the use throughout of industry-standard components facilitates easy replacement of parts if needed. Or CMC can carry out any necessary repairs but will charge for costs of parts plus labour and carriage. CMC has many years of experience in scanning electrode techniques, our first publication on this topic being in 1991. We have 15 years' experience with scanning reference electrodes and CMC Ltd supply advanced equipment which produces the example pictures on this website, including the powerful CMC graphics programme (used for most of the pictures), rotatable in two axes in 1-degree steps.

Repairs by CMC would be carried out at CMC's premises.
Clients are responsible for adequately packing and for the cost of shipping the equipment to CMC.
Return shipment will be paid for by CMC Ltd during the guarantee period.

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