ASTM C633:13 pdf free download – Standard Test Method for Adhesion or Cohesion Strength of Thermal Spray Coatings.
5.1.3 The adhesion strength of the bonding agent shall be determined each time this test method is performed. This shall be done by using the bonding agent to attach a loading fixture to a second loading lixture, in accordance with 6.5, except that the coated substrate fixture of 6.5 is replaced with the second loading fixture.
Note 4—One reason for testing the bonding agent each time is to detect improper preparation of the agent if it is a two-pan mix. Another reason is that adhesion strength generally decreases with age of the unused agent. If strength is lower than required. more adhesive bonding agent shall be prepared and tested, or the agent shall be discarded and replaced.
6. Test Specimens
6.1 Substrate and Loading Fixtures— Each test specimen is an assembly comprising a substrate fixture, to which the coating is applied. and a loading fixture. The substrate and loading fixtures shall each be circular, solid cylinders of no less than 1.5 in. in length, or as agreed upon by the manufacwrer and customer. A suggested detail for either fixture is shown in Fig. 2. One end of each fixture shall be adapted for attachment to the self-aligning loading devices of the tension testing machine. Both ends of each fixture shall have faces parallel to each other and normal to the loading axis. The facing diameters shall be not less than 0.9 in. (23 mm), nor more than 1.0 in. (25 mm). The diameters of the two fixtures shall be the same and shall be measured so that the error is no greater than 0.5 %.
Nom 5—In Appendix XI, an alternative substrate and fixture arrangement is provided that has proved cost effective and simple.
6.1.1 Material for Substrate Fixture— The substrate fixture shall be constructed of metal, preferably metal intended for use as the substrate for the coating. If no such substrate material is specified, the substrate fixture shall be SAE 1018 or 1020 steel.
NOTE 6—If desired because of cost or case of fabrication, it may be suitable to attach or bond a layer of the specified substrate material to a fixture formed of any convenient meal. Such a layer of substrate material need not be metal. The layer must be substantially thicker than the possible depth of effects on the substrate, such as recrystallization or diffusion zones, that may result from applying the coating. A layer greater than 0.1 in. (2.5 mm) thick should be sufficient.
6. 1 .2 Material for Loading Fixture—The loading fixture shall be constructed of metal, but material is otherwise optional.