Overview
ISO 21714:2018 specifies a standardized test method for determining the density of thick ceramic coatings using the Archimedes principle at ambient temperature. Applicable to fine ceramics, advanced ceramics, and technical ceramic coatings thicker than 0.1 mm, this standard covers critical types including thermal barrier coatings and wear-resistant coatings on both metal and ceramic substrates. The document provides detailed guidelines on test piece preparation, test procedures, data collection, and calculation formulas, ensuring precise and repeatable measurement of coating density.
This ISO standard plays a vital role in quality control and performance evaluation of ceramic coatings used in industrial applications, enabling manufacturers and researchers to maintain material consistency and optimize coating properties.
Key Topics
-
Scope and Applicability
Focus on thick ceramic coatings (>0.1 mm) including thermal barriers and wear-resistance layers on diverse substrates.
-
Test Piece Types and Preparation
- Type A: Rectangular parallelepiped samples with single-face coating; involves grinding off the coating to measure substrate density.
- Type B: Test pieces with complex shapes where coating removal is impossible; substrate density measured before coating application.
-
Measurement Principles
Utilizes the Archimedes method to determine density by comparing coated and uncoated sample densities, accounting for mass ratios and substrate-coating interfaces.
-
Apparatus and Equipment
- Density testing apparatus compliant with ISO 18754.
- Vernier caliper (precision 0.02 mm per ISO 3611) for dimension measurements.
- Optical/electronic microscopes for coating thickness assessment with magnification of 1000x or higher.
-
Calculation Methods
Density of ceramic coatings is calculated with a precise formula relating the dry mass of substrate and coated samples with their measured densities.
-
Test Conditions and Reporting
Environmental factors such as temperature and relative humidity must be recorded. The test report includes detailed sample descriptions, measurement results, and testing conditions.
Applications
-
Thermal Barrier Coatings (TBCs)
Ensuring optimal density helps improve thermal insulation and longevity of engine and turbine components.
-
Wear-Resistance Coatings
Accurate density measurement aids in predicting durability and mechanical resistance in abrasive environments.
-
Advanced Ceramic Manufacturing
Quality control of ceramic coatings in electronics, aerospace, and automotive industries benefits from reliable density measurement.
-
Research and Development
Material scientists and engineers use ISO 21714 to characterize novel ceramic materials and coating techniques.
-
Failure Analysis and Process Optimization
Detecting density anomalies allows for early identification of defects such as porosity, helping refine coating processes.
Related Standards
-
ISO 18754 – Specifies the Archimedes method for density and apparent porosity determination in fine ceramics, serving as the basis for density measurement methodology in ISO 21714.
-
ISO 3611 – Defines dimensional measuring equipment for external measurements, ensuring accuracy in sample dimension recording.
-
Industry-Specific Coating Standards
Complementary standards pertaining to specific ceramic coatings’ performance criteria and testing protocols in aerospace, automotive, and electronics sectors.
Keywords: ISO 21714, ceramic coatings density measurement, fine ceramics testing, Archimedes method, thermal barrier coatings, wear-resistant coatings, ceramic substrate, coating thickness measurement, advanced ceramics standard, test method for density, ceramic coating quality control.
Open preview (PDF)Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for determining density of ceramic coatings
