1. Scope

1.1 This test method covers the nanoscratch method for determining the resistance of paint coatings on smooth flat surfaces to scratch/mar.

1.2 Previous methods used in scratch/mar evaluation first physically scratch or mar a samples surface with multiple contact cutting, and then use visual inspection to assign a ranking. It has been recognized that loss of appearance is mainly due to surface damages created. The philosophy of this method is to quantitatively and objectively measure scratch/mar behavior by making the evaluation process two steps with emphasis on surface damages. Step one is to find the relationship between damage shape and size and external input (such as forces, contact geometry, and deformation). Step two is to relate damage shape and size to visual loss of luster. The first step is covered by this method; in addition, a survey in the appendix provides an example of an experiment to relate the damage to the change in luster.

1.3 There are three elementary deformation mechanisms: elastic deformation, plastic deformation and fracture; only the latter two both contribute significantly to mar. This method evaluates scratch/mar based on the latter two damage mechanisms.

1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D609 Practice for Preparation of Cold-Rolled Steel Panels for Testing Paint, Varnish, Conversion Coatings, and Related Coating Products

D823 Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels

D1005 Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers

D1044 Test Method for Resistance of Transparent Plastics to Surface Abrasion

D1186 Test Methods for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to a Ferrous Base

D1400 Test Method for Nondestructive Measurement of Dry Film Thickness of Nonconductive Coatings Applied to a Nonferrous Metal Base

D3363 Test Method for Film Hardness by Pencil Test

D3924 Specification for Environment for Conditioning and Testing Paint, Varnish, Lacquer, and Related Materials

D5178 Test Method for Mar Resistance of Organic Coatings

D6037 Test Methods for Dry Abrasion Mar Resistance of High Gloss Coatings

D6279 Test Method for Rub Abrasion Mar Resistance of High Gloss Coatings

G171 Test Method for Scratch Hardness of Materials Using a Diamond Stylus

Keywords

coatings; gloss; mar or organic coating mar resistance; scratch resistance;

ICS Code

ICS Number Code 87.040 (Paints and varnishes)

DOI: 10.1520/D7187-05

ASTM International is a member of CrossRef.