Coating thickness by Calotest

CalotestThe Calotest provides quick, simple and inexpensive determination of coating thicknesses. A rotating sphere, with a known diameter (Ø ball) is pressed on the coating surface with a preselected load. Both the position of the sphere relative to the sample and the contact load are constant. Upon adding abrasive slurry to the contact zone, a depression with the shape of a spherical cap is abraded into both the coating and the substrate.

Optical inspection of the depression reveals the projected surfaces of the abraded coating and substrate sections. By measuring the parameters X and Y, the thickness of the coating D can be calcuted by a simple geometrical equation.

The Calowear system extends the Calotest principle by incorprating a force sensor, a revolution counter and an automated slurry dispenser. A steel ball rolls on the test sample and a slurry composed of water and SiC particles falls continuously onto the ball at the contact region. The slurry wears the substrate in a controlled manner and thus assures highly reproducible results.

The normal force between the sphere and the specimen is measured. The rotational motion of the sphere is also measured. The rotation of the sphere against the specimen in the presence of the abrasive slurry generates a wear crater. By comparing the geometry of the crater for different periods of wear time, the thickness of the coating and the wear rate of the coating and the substrate can be determined precisely.



 //// Features

> Spherical abrasion test method                                                      
> Determination of coating thickness
> Applicable to a wide variety of mterials
> Fine and extra fine polishing slurries
> Available in Compatct or Industrial configurations              



 //// Options

> Optical measuring system with automatic thickness calculation


csm title Related documents

Application Bulletin n°37

Physical characterization of coated surfaces - Part I : Instrumented Indentation

Application Bulletin n°09

- MST Swinging Module for variable frequency scratch testing
- Combined NHT/SFM for investigation the mechanical properties of Cr2O3 thin films
- New Industrial Calotest allows greater fl exibility for measuring over/undersized samples

Application Bulletin n°08

- New Industrial Calotest for improved coating thickness determination
- Micro Hardness Tester (MHT) for fracture toughness determination of brittle materials
- New Tribometer option for reciprocating wear testing of plasticised tickets
- Low-load Micro Scratch Tester (MST) for characterization of thin polymer films

Application Bulletin n°05

- Finer particle size allows better coating characterization with the Calotest
- Combined NHT/SFM for characterization of coated systems

Application Bulletin n°03

- New integrated SFM objective for better characterization of NHT indentations
- Modified Micro Scratch Tester (MST) for im­proved force resolution at low loads
- Hard coating characterisation with the CSM Tribometer