DIN - DVS 2310-1
Guide to the production of microsections and the evaluation of thermally sprayed coatings
|Publication Date:||1 July 2013|
|ICS Code (Surface treatment):||25.220.20|
The Leaflet DVS 2310-1, 1984 issue, had to be revised because the results of a round robin test showed that the recommended preparation method for bonded systems with a ceramic layer did not produce a satisfactory result. The layers are therefore not prepared.
Another reason was due to the fact that the once preferred method of manual microsection preparation must be regarded as being qualitatively inadequate. Grinding and polishing processes must be carried out automatically or using suitable mechanised systems in order to be able to keep the preparation parameters contact pressure, speed and lubricant dosage constant and reproducible.
After completion of the round robin test, where the preparation for grinding was primarily based on the use of SiC paper, new grinding methods have been introduced recently under the consideration of newly designed diamond-tipped grinding discs with a different grain size, which are taken into account in this revised version in order to meet the state of the art requirements.
With regard to the requirements of the layers and its evaluation, there may be significant differences in the quality requirements since they are being used in different industries. The permissible irregularities determined during the materialographic examination for the respective application must be defined by the contracting parties with reference to the components.
With certain applications, roughness and macro-hardness measurements can be of help especially for comparative nominal-actual statements during the materialographic examination.
Thermally sprayed coatings can be metallic or ceramic or a combination of metallic and ceramic parts or plastic parts [1; 3; 4]. In practice, quality control is only possible to a limited extent using non-destructive test methods [2; 6]. Materialographic examinations can however be used to evaluate the characteristic features of a sprayed coating such as thickness, structural texture (structure, porosity), bond to base material and hardness (e.g. of individual phases).
The combination of hard and soft, brittle and ductile, wear-resistant and non wear-resistant materials or microstructure constituents (phases) in the sprayed coating/base material compound and/or within the layer requires some special characteristics to be observed during the materialographic production of microsections [8; 16; 17; 19; 20; 21].
The following work steps which describe the production of microsections, give full details of the correct removal and microsection preparation of specimens with thermally sprayed coatings.