Home / Corrosion testing / Specimen preparation

Specimen preparation

Scratch tools to apply defined scratches on specimens for short-term and endurance corrosion tests.

 


It is a common method to prepare coated test panels for corrosion tests by applying various linear scratches in a vertical, horizontal or intersecting manner in such a way that the resistance of the coating system against rust formation under the coating can be tested. Beside the use of a test tip according to "van Laar" as scratch tool, frequently the use of a test tip according to "Clemen" (included in the scope of supply) is specified for this procedure. Sometimes a single test tip for cross hatch cutting tests may also be used. Depending on the requirements the user has to meet, these test tips used as scratch tools are appropriate tools to produce defined scratches on coating surfaces provided for accelerated corrosion tests, such as condensation water tests, gas corrosion tests, salt spray tests, continuous or alternate immersion tests and accelerated weathering tests etc..

Product Examples:

Scratching Tool acc. to van Laar, Model 426

The Sratching Tool acc. to van Laar is a handy universal tool: for producing accurately defined incisions on the surface of the coating in preparation of forced corrosion tests, such as salt spray, continuous or intermittent immersion, accelerated weathering, gas corrosion and humidtiy tests.

Scratch Stylus acc. to Sikkens, Model 463

The scratching stylus method is used to produce defined damages (cracks) on coated test panels to be used in corrosion tests, as, for instance, the Fog Spray Test acc. to DIN EN ISO 9227 with the ERICHSEN Corrosion Testing Apparatus, Models 606 and 608. This method provides a criterion for the evaluation of the extent or influence of corrosion underneath a coating and its effect on the adhesion. The length of the lateral damage underneath the coating serves as a measure of the corrosion protection factor.

SCRATCHMARKER 427

The SCRATCHMARKER 427 consists of a basic unit including scratch tool (diameter 0.5 mm, point radius 0.25 mm) made of tungsten carbide, a graduated dial (max. scratch depth approx. 500 microns, graduation 25 microns) and a ruler. In addition the necessary calibrating device for adjusting the depth of the scratch is supplied with the instrument. The compact construction of the SCRATCHMARKER as well as the practical ruler enable a fatigue-free operation of the instrument even if there is a lot of work to be done.