ASTM F1044 – Standard Test Method for Shear Testing of Calcium Phosphate Coatings and Metallic Coatings
This test method covers shear testing of continuous calcium phosphate coatings and metallic coatings adhering to dense metal substrates at ambient temperatures. It assesses the degree of adhesion of coatings to substrates, or the internal cohesion of a coating in shear, parallel to the surface plane. This test method consists of subjecting a specimen assembly composed of one coated and one uncoated component to a shear load. The components to be tested may be bonded together directly by thermomechanical means (for example, sintering or diffusion bonding) or may be bonded together by use of a polymeric adhesive. The adhesive may be in film form or bulk form, but it must have a minimum bulk shear strength of 34.5 MPa [5000 psi] or as great as the minimum required adhesion or cohesion strength of the coating, whichever is greater.
The shear test method is recommended for shear testing of calcium phosphate and metallic/substrate combinations and can provide information on the adhesive or cohesive strength of coatings under a uniaxial shear stress. The test method may be useful for comparative evaluation of adhesive or cohesive strengths of a variety of types of coatings. Information developed using this test method may be useful for certain quality control and design purposes. The test method should not be considered to provide an intrinsic values for utilization directly in making calculations such as determining the ability of a coating to withstand specified environmental stresses.
Example of test results are shown below.