Determination of coating, adhesive and bonding strength by means of an innovative centrifuge technology
Bonding is used in a wide field of industries for various purposes. There are manifold reasons for applying joining technology like the ability to connect different material classes, a load distribution over the entire joining area or the combination with other objectives, like electric conductivity or sealing purpose. The wide usage of coating and bonding in many industrial sectors causes a great need for testing their mechanical properties. The surface preparation and optimisation of the assembly components is of great interest too.
Another major subject is the determination of adhesive strength of coated sample systems. Nearly all surfaces of modern industrial and customer products are coated. Nowadays there is an increasing demand for composite materials like CFC and CFRC used for light-weight construction, e.g. rotors of wind energy plants. Beside other properties the coating strength is of essential interest.
The quality and durability of bonded joints, coated systems (paint, varnishes) and composites depend on various factors. Therefore effective quantitative tests to determine adhesive, bonding or coating strength are of great need for R&D and QC. The only testing method to obtain quantitative results in terms of force per area is the “plot” or “pull-off” test. As a currently used technique to quantify strength tensile testing machines are used. This approach can analyze samples only one by one, especially the sample preparation by clamping consumes time and geometrical restrictions have to be found.
In this talk we present a new measuring principle, which employs an always radially directed centrifugal force to generate the load and describe the multi-sample centrifuge technology in detail including a reproducible method for sample preparation, surface pre-treatment procedures, measuring protocol and result analysis. After presenting some basic results, we focus especially on polymer layers on polymer substrates, polyurethane layers on metal substrates as well as thick adhesive layers and rubber-textile-composite with considerable strain rates.