standardized and customized corrosion tests

Cetim-Cermat is able to respond to your questions relating to corrosion tests, whether in terms of a standardised service provision, in terms of choice of material(s) or coating(s), or in terms of technical support to define and implement specific tests.

Standardised corrosion tests:

These tests are perfectly defined through standards (ISO, AFNOR, ASTM and NACE) or specifications. The following can be mentioned:

  Atmospheric corrosion tests:

• Salt spray, Cass test,
• Kesternich test (SO2 atmosphere),
• Cyclical test (BS – T° - %HR): 3C, ECC1, etc.
• Immersion tests with measurement of weight losses, etc.

Pitting Test highlighting the non-passivated characteristic of a stainless steel tube

  Tests of resistance to a given form of corrosion:

• Corrosion under stress (MgCl2, NaCl, etc.)
• Intergranular corrosion (Huey, Monypenny Strauss, etc.)
• Corrosion by pitting,
• Selective corrosion (dezincification, etc.)
• Exfoliation corrosion, etc.

Electrochemical tests performed in a given environment:

These tests allow access to certain parameters characteristic of the various forms of corrosion :

• Polarisation curves and plot of TAFEL straight lines (generalised corrosion),
• Polarisation resistance measurements (corrosion speed),
• Corrosion potential, pitting and repassivation potential (corrosion by pitting),
• Galvanic coupling,
• The Electrochemical impedance is used to describe the behavior of coating (passivation layer, varnish, paint, metal coating ...), principally from the determination of resistance existing during the transfer of forces. 

Resistance Test to dezincification (brass) on coated samples

These measures can be used to monitor a complex test

Examples:
Determining which grade of stainless steel can withstand a waterborne paint
Checking the corrosion resistance of a new coating by electrical impedance

Analysis of special corrosion, custom testing

These tests are defined after considering the risk of corrosion (which form(s) of corrosion and in which area (s)?) related to conditions of use.
In this case, all conditions can be envisaged, whether it is the duration or the assembly.
We possess an autoclave made of Hastelloy C276, ready to test different materials in aggressive environments (see below the features of the device).

Help in defining the suitable tests

Whether it relies in the choice of materials or simply verifying the quality of your suppliers’ parts, we are here to help you determine which test, especially in terms of duration, is best suitable for you.

Examples:
Confined boiling test specially designed for a mixture of strong acids.
Resistance to corrosion test in deionised water of a thin cobalt based alloy tube

Specific materials used for the analysis and expertise of corrosion:

• 3 tanks of salt spray
• a SO2 chamber
• 4 potentiostats (including a portable one)
• 2 frequency response analyzers (including a portable one)
• 1Hastelloy C276 autoclave / lining EFF: 13 liters, 250 ° C, 200bars