ASTM C633-13 pdf free download.Standard Test Method for Adhesion or Cohesion Strength of Thermal Spray Coatings.
1.1 This test method covers the determination of the degree of adhesion (bonding strength) of a coating to a substrate or the cohesion strength of the coating in a tension normal to the surface. The test consists of coating one face of a substrate fixture, bonding this coating to the face of a loading fixture, and subjecting this assembly of coating and fixtures to a tensile load normal to the plane of the coating. It is adapted particularly for testing coatings applied by thermal spray, which is defined to include the combustion flame, plasma arc, two-wire arc, high-velocity oxygen fuel, and detonation processes for spraying feedstock, which may he in the form of, wire, rod, or powder.
2. Referenced Documents
2.1 ASTM Standards.
E4 Practices for Force Verification of Testing Machines
3. Significance and Use
3.1 This test method is recommended for quality control, acceptance testing; or it may help to develop or qualify a thermal spray operator’s equipment and procedure or to aid in developing thermal spray coatings with improved adhesion and integrity.
3.2 This test method is useful for comparing adhesion or cohesion strengths of coatings of similar types of thermal spray materials. The test should not he considered to provide an intrinsic value for direct use in making calculations, such as to determine if a coating will withstand specific environmental stresses. Because of residual stresses in thermal spray coatings, actual strength depends upon the shape of the particular coated part. Also, in use, a coating may be stressed in a more complex manner than is practical for a standard test.
4. Apparatus
4.1 A tension testing machine shall conform to the requirements of Practices E4. The loads used in determining the adhesion or tensile strength shall be within the loading range of the testing machine, as defined in Practices E4. Permissible variation shall be less than 1 .0 %. It shall he possible to apply increasing tensile load at a constant rate of cross-head travel between 0.030 in.frnin (0.013 mmls) and 0.050 in./min (0.021mm/s). The machine shall include a load-indicating device that registers the maximum load applied before rupture occurs.
4.2 Self-aligning devices, for applying the tensile load to the assembly of the coating and tixtures, shall not permit eccentric load or bending moment to the specimen. Self-alignment is often provided by the manufacturer as an integral part of the testing machine. An alternative, satisfactory apparatus is shown in Fig.1, which also shows methods of connecting the self-aligning apparatus to an assembled test specimen.ASTM C633 pdf download.