Fracture evaluation of thermally sprayed coatings in dependence on cohesive strength

6th International Conference on Fracture Fatigue and Wear

Schubert, J.^1 ; esánek, Z.^1

Výzkumný A Zkuební Ústav Plze, Pilsen, Czech Republic^1

关键词: Coating characteristics;    Cohesion strength;    Cohesive strength;    Commercial sector;    Customer demands;    Fracture evaluation;    Scratch test method;    Thermally sprayed coatings;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/843/1/012007/pdf
DOI  :  10.1088/1742-6596/843/1/012007

来源: IOP

【 摘 要 】

Measuring the cohesive strength of thermally sprayed coatings is relatively difficult matter, which can be accessed in many directions. This issue is nowadays solved by use of Scratch test method. This method is not completely sufficient for the cohesive strength testing because the coating is under load of combined stresses during the Scratch test. The reason to develop this method was need for exact measurement of tensile cohesion toughness of thermally sprayed coatings, which could provide results as close to a classic tensile test as possible. Another reason for development of this method was the impossibility of direct comparison with results obtained by other methods. Tested coatings were prepared using HP / HVOF (Stellite 6, NiCrBSi, CrC-NiCr and Hastelloy C-276). These coatings were selected as commonly used in commercial sector and also on because of rising customer demand for ability to provide such coating characteristics. The tested coatings were evaluated in terms of cohesive strength (method based on tensile strength test). Final fractures were evaluated by optical microscopy together with scanning electron microscopy and EDS analysis. As expected higher cohesive strength showed metallic coatings with top results of coating Stellite 6. Carbide coatings showed approximately third of the cohesion strength in comparison with metal based coating.