Used in a Comparison of Tests Evaluating the Bond Strength of Thermal Sprayed Coatings Master Bond Inc. 154 Hobart Street, Hackensack, NJ 07601 USA Phone +1.201.343.8983 | Fax +1.201.343.2132 | [email protected]

CASE STUDY EP15ND-2: Used in a Comparison of Tests Evaluating the Bond Strength of Thermal Sprayed Coatings Overview of EP15ND-2 Master Bond EP15ND-2 is a single component, heat curing epoxy specifically designed for testing the strength of thermal sprayed coatings as indicated by ASTM C633. Featuring exceptionally high tensile strength exceeding 12,000 psi, as well as unlimited working life at room temperature, the formulation is 100% reactive, forming dimensionally stable bonds with minimal shrinkage upon cure. In this study, EP15ND-2 was utilized per the ASTM C633 test to analyze the tensile...

Table 1: Coating type and spray techniques. Coating Type The scratch test deveIoped in the study empIoyed a diamond indenter (radius of 200 pm) for Rockwell hardness testing. The indenter was drawn across the cross-section of the specimen, from the substrate through the coating into the epoxy, with a load of 16N at a rate of 3 mm/min. The cone area left by the indenter is then measured and inversely correlated to the cohesive strength of the coating, with larger areas representing lower cohesive strength (Figure 1). The ASTM C633 test was carried out using a tensile strength testing machine (Instron...

bond strength of more than double of the Mo specimen (75 and 32 MPa respectively), but these coatings had similar cone areas of 13 and 14 mm2 respectively, leading to the conclusion that there is no apparent relationship between the two measurements. In fact, the authors hypothesize that the discrepancies in the results arise because the two tests measure different aspects of the cohesion/adhesion phenomena. The scratch test “induces a cohesive failure through the thickness of the coating” whereas ASTM C633 “measures the lowest strength across the coating, which in thermal sprayed coatings tends...