ASTM D4366-16 (R2021) pdf free download.Standard Test Methods for Hardness of Organic Coatings by Pendulum Damping Tests.
1 .1 These test methods cover the use of pendulum damping testers in the determination of hardness of organic coatings that have been applied to acceptably plane rigid surfaces, such as a metal or glass panel.
1 .2 Two test methods based on different pendulum types are covered as follows:
1 .2.1 Test Method A—Konig Pendulum Hardness Test.
1.2.2 Test Method B—Pcrsoz Pendulum Hardness Test.
1 .3 This standard is similar in content (but not technically equivalent) to ISO 1522.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
3. Terminology
3. 1 Definitions of Terms Specific to This Standard:
3. 1 . 1 König hardness, n—time in seconds for the swing amplitude of the Konig pendulum to decrease from 6 to 3°.
3.1 .2 Persoz hardness, n—time in seconds for the swing amplitude of the Persoz pendulum to decrease from 12 to 40
4. Summary of Test Methods
4.1 A pendulum resting on a coating surface is set into oscillation (rocking) and the time for the oscillation amplitude to decrease by a specified amount measured. The damping time is influenced by a combination of physical properties, amongst hardness, elasticity. coetlicient of friction and shore of the sample under test. The damping time decreases with the decrease of hardness or an increase of elasticity or coefficient of friction.
5. Significance and Use
5.1 The pendulum damping test has been found to have good sensitivity in detecting differences in coating hardness, where hardness is defined as resistance to deformation.
5.2 The two procedures given in these lest methods embody the principle that the amplitude of oscillation of a pendulum touching a surface decreases more rapidly the softer the surface. However, these test methods differ in respect to pendulum dimensions, and period and amplitude of oscillation.
5.3 In general, the damping time of the Konig pendulum is approximately half that of the Persoz pendulum.ASTM D4366 pdf download.