ASTM D7027: Scratch Mar Coating Surface Testing Services
Accredited ASTM D7027 scratch mar coating surface testing from Infinita Lab, performed to the exact standard requirements - accurate, reproducible results with full documentation for compliance, R&D, and quality control programs.
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- Overview
- Scope, Applications, and Benefits
- Test Process
- Specifications
- Instrumentation
- Results and Deliverables
What Is ASTM D7027 Scratch Mar Coating Surface?
ASTM D7027, Standard Test Method for Evaluation of Scratch Resistance of Polymeric Coatings and Plastics Using an Instrumented Scratch Machine, describes a laboratory procedure that produces and quantifies surface damage under controlled, automated conditions. ASTM Subcommittee D20.10 maintains the method. The current active edition is D7027-20, which supersedes the earlier D7027-13 and D7027-05 versions. The central idea is simple: a machine makes the scratch, not a hand, so load, speed, and stylus geometry stay controlled and the operator’s influence is minimized. A hard stylus is drawn across the specimen surface while the instrument records the forces involved. That allows the scratch coefficient of friction to be determined alongside scratch depth and visible damage. Published descriptions of the method refer to a spherical stainless steel stylus about 1 mm in diameter, moved at constant speed under either a constant or a progressively increasing normal load. With a progressive load, damage develops in stages. The standard pays particular attention to stress-induced whitening, the visible damage that appears at a critical normal load and matters most for aesthetic surfaces. Many polymers are viscoelastic and can partially recover, so the standard recommends allowing 24 hours for recovery before residual scratch depth is assessed. It also notes that polymer properties vary with temperature, so specimen conditioning and a consistent test environment are required for reproducible results. The method serves three purposes: evaluating the scratch resistance of a given material, ranking relative performance among different materials, and determining the scratch coefficient of friction. D7027 is technically related to ISO 19252, which addresses scratch properties of plastics, though the two documents differ in details such as how the critical load is defined. D7027 addresses scratch resistance only. Separate standards cover Mar resistance.
Applications and Benefits of ASTM D7027 Scratch Mar Coating Surface Testing
Scope
ASTM D7027-13 applies to polymeric coatings and plastic substrates and assesses:
- The standard describes a laboratory procedure that uses an instrumented scratch machine to produce and quantify surface damage on polymeric materials.
- Polymeric coatings and plastics fall under it, coated surfaces and molded plastic specimens alike.
- Automation characterizes scratch resistance while keeping user-influenced variability to a minimum.
- A specific material’s scratch resistance can be evaluated under defined, repeatable conditions.
- Relative scratch performance of different polymers or coating formulations can be ranked.
- Recorded force data provides a means of determining the scratch coefficient of friction.
- Stress-induced whitening, the visible damage that appears at a critical normal load, is addressed too, and it’s relevant to appearance-critical parts.
- Viscoelastic and self-healing polymers recover over time. The standard recommends waiting 24 hours before measuring residual scratch depth.
- Because polymer mechanical behavior depends strongly on temperature, consistent specimen conditioning and test environment are required.
- Scratch resistance only. Mar resistance of high gloss coatings is a separate property addressed by other standards such as ASTM D6279.
Applications
- Automotive interior and exterior plastic components, where whitening and visible scratches affect perceived quality.
- Polymeric coatings and clear coats, automotive and industrial, that must retain their appearance in service.
- Molded plastics in consumer product housings, appliance panels, and electronic device casings.
- Material development, such as comparing resin grades, fillers, additives, and surface-modified polymers.
- Quality control and incoming inspection of molded or coated parts against an internal scratch-resistance specification.
- Self-healing or viscoelastic polymer systems, evaluated through residual scratch depth after a recovery period.
Benefits
- Automated scratching reduces operator influence and improves repeatability compared with manual scratch methods.
- From a single scratch track, a progressive load can reveal the critical load at which visible damage begins.
- Force recording gives you the scratch coefficient of friction on top of a visual damage assessment.
- Objective ranking of candidate materials, coatings, or formulations becomes possible.
- Because conditioning and recovery requirements are documented, results are comparable across batches and sites.
- Supplier qualification, specification writing, and product development decisions all draw on the quantitative data.
Our ASTM D7027 Testing Procedure
Specimen Setup
The coated or plastic test specimen is mounted on the scratch test stage and leveled.
1Progressive Scratch
A diamond or carbide stylus is drawn across the surface under a linearly increasing normal force; speed and force range are specified.
2Surface Inspection
The scratch track is inspected visually and under microscopy to identify the onset of visible scratching and measure damage dimensions.
3Data Analysis
Critical force, scratch width, and depth profile are recorded; results are reported with replicate statistics.
4ASTM D7027 Test Parameters and Requirements
| Parameter | Details |
|---|---|
| Test Principle | Progressive load scratch with spherical stylus |
| Stylus Tip | Diamond or stainless steel; 1 mm radius |
| Force Range | 0–30 N (progressive or fixed load) |
| Scratch Speed | 100 mm/min |
| Measured Outputs | Critical scratch force (Fc), scratch width, depth |
- Instrumented Scratch Machine – an automated linear scratch tester that moves the stylus at a controlled speed and applies a constant or progressive normal load.
- Scratch Stylus (Spherical Tip) – a hard tip of defined geometry. It creates the scratch track on the specimen surface.
- Normal and Tangential Force Sensors – record the loads during the scratch, which is how critical load and friction coefficient get calculated.
- Optical Microscope or Scanning System – locates the onset of whitening and lets the scratch track be inspected and measured.
- Profilometer or Depth Measurement System – quantifies residual scratch depth after the recovery period.
- Environmental Conditioning Chamber – holds specimens and test conditions at a consistent temperature before and during testing.
Equipment and Instrumentation Used for ASTM D7027 Testing
What You Receive: Test Report, Data, and Certification
- The critical normal load at which stress-induced whitening or other visible damage begins along the scratch track.
- Depth of the scratch, plus residual scratch depth measured after the 24-hour recovery period.
- Scratch coefficient of friction, calculated from the recorded normal and tangential forces.
- Images of the scratch track, taken by microscope or scan, documenting the damage progression.
- Comparative ranking of the materials or coatings tested under identical conditions.
- A complete test report listing specimen details, conditioning, stylus, load mode, speed, and results.
ASTM D7027 Scratch Mar Coating Surface FAQs
Fc is the normal force at which a scratch first becomes visible to the naked eye under standard lighting; it is the primary measure of scratch resistance in this test.
Both standards use a progressive load scratch technique and spherical stylus, and their results are generally comparable; D7027 is the ASTM version, while ISO 19252 is the international equivalent.
Yes — ASTM D7027 is commonly used to evaluate the scratch resistance of automotive clear coat systems and interior trim coatings.
Not always — scratch resistance depends on a combination of hardness and elasticity; some softer materials recover elastically and show good scratch resistance despite low hardness.
Yes — the scratch test leaves a visible mark on the specimen; separate specimens are required for each test condition.
A controlled stylus or indenter is drawn across the material surface under a specified load, creating a scratch. The resulting damage, scratch width, depth, or critical load is measured to evaluate scratch resistance. ASTM D7027 uses an instrumented scratch machine for polymeric coatings and plastics.
Mar resistance measures a material’s ability to resist visible surface damage from light scratching or rubbing. A controlled contact is applied to the surface, and the resulting marks, whitening, or surface damage are evaluated to compare resistance.
Why Choose Infinita Lab for Scratch Mar Coating Surface Testing
When your Scratch Mar Coating Surface results have to hold up - for compliance, a customer audit, or an engineering decision - ASTM D7027 accuracy and an unbiased third-party report matter more than price. Infinita Lab routes your ASTM D7027 scratch mar coating surface testing to ISO/IEC 17025-accredited U.S. partner labs with hands-on method experience, so you get defensible data, transparent reporting, and turnaround times built around your project deadline - not ours.
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