ASTM E384 Microhardness Testing Guide – Vickers & Knoop Analysis
ASTM E384 defines the procedure for measuring microhardness of materials using the Vickers (HV) or Knoop (HK) diamond indentation methods with loads from 1 to 1000 gram-force. Because the indentations are microscopic, this test is used where conventional Rockwell or Brinell hardness testing cannot — thin PVD/CVD coatings, individual weld zones, carburized and nitrided case layers, individual grains or phases in a microstructure, and electronic components. Infinita Lab performs ASTM E384 microhardness testing with metallographic sample preparation, automated stage traverses for case depth profiling, and full indentation imaging, delivering HV or HK values with measurement uncertainty per ASTM E384 requirements.
TRUSTED BY
- Overview
- Scope, Applications, and Benefits
- Test Process
- Specifications
- Instrumentation
- Results and Deliverables
ASTM E384 Microhardness Testing Overview
ASTM E384 is a standard test method for determining the microhardness of materials using indentation techniques such as the Vickers and Knoop tests. It is designed to evaluate small volumes, thin sections, coatings, and microstructural phases for which conventional hardness testing is unsuitable.
The test applies very low loads (typically in grams or kilograms) to produce small indentations that can be measured under a microscope. It provides detailed hardness information at the micro-scale, making it valuable for analyzing material properties at specific regions or phases.
Scope, Applications, and Benefits
Scope
ASTM E384 evaluates:
- Microhardness of materials using the Vickers and Knoop methods
- Hardness of thin coatings and surface layers
- Phase-specific hardness in microstructures
- Case depth and hardness gradients
- Small or delicate material samples
Applications
- Metallurgical and materials research
- Coatings and thin films
- Heat-treated and case-hardened materials
- Electronics and micro-components
- Quality control and failure analysis
Benefits
- Enables hardness measurement at the micro-scale
- Suitable for thin or small samples
- Provides localized hardness information
- Supports microstructural analysis
- High precision and repeatability
ASTM E384 Test Process
Sample Preparation
Surface is polished to a smooth, mirror-like finish.
1Indentation
Low load is applied using Vickers or Knoop indenter.
2Measurement
Indentation size is measured using optical microscope.
3Data Analysis
Hardness value is calculated based on indentation dimensions.
4ASTM E384 Technical Specifications
| Parameter | Details |
|---|---|
| Test Principle | Micro-indentation hardness measurement |
| Indenter Types | Vickers (diamond pyramid), Knoop (elongated diamond) |
| Load Range | ~1 gf to 1000 gf |
| Dwell Time | ~10–15 seconds (typical) |
| Sample Type | Metals, coatings, ceramics |
| Measured Outputs | Vickers hardness (HV), Knoop hardness (HK) |
Instrumentation Used for Testing
- Microhardness tester (Vickers/Knoop)
- Diamond indenter (Vickers or Knoop)
- Optical microscope with measurement system
- Polishing and sample preparation tools
- Load application system
- Data acquisition and analysis software
Results and Deliverables
- Microhardness values (HV or HK)
- Indentation images and measurements
- Hardness distribution across the sample
- Case depth or coating hardness analysis
- Material performance evaluation
- Test report
Partnering with Infinita Lab for Optimal Results
Infinita Lab addresses the most frustrating pain points in the ASTM E384 testing process: complexity, coordination, and confidentiality. Our platform is built for secure, simplified support, allowing engineering and R&D teams to focus on what matters most: innovation. From kickoff to final report, we orchestrate every detail—fast, seamlessly, and behind the scenes.
Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you. Request a Quote
Frequently Asked Questions
ASTM E384 is a standardized method for determining the microindentation hardness of materials using small applied loads and optical measurement of indentation size. It measures hardness using either a Vickers or Knoop diamond indenter under controlled conditions.
This test is essential for evaluating hardness on a microscopic scale, especially in thin coatings, small components, or microstructures. It helps ensure material quality, uniformity, and performance in precision-engineered products.
A small load is applied using a diamond indenter for a specific dwell time (usually 10–15 seconds). After unloading, the indentation size is measured microscopically. Hardness is calculated based on the applied load divided by the surface area of the indentation.
Vickers uses a symmetrical diamond pyramid indenter, while Knoop uses an elongated indenter, making it more suitable for very thin materials and brittle samples requiring shallow indentation.
The test uses low loads typically ranging from 1 gram-force to 1000 gram-force, allowing precise indentation measurement without damaging small or delicate samples.
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