ASTM C633-13(2021) PDF

Overview

ASTM C633-13(2021) – Standard Test Method for Adhesion or Cohesion Strength of Thermal Spray Coatings specifies a standardized procedure to determine the adhesive (bonding) and cohesive strength of thermal spray coatings applied to a substrate. Developed by ASTM, this test method is essential for quality control, acceptance testing, operator qualification, and the development of improved thermal spray coatings in industrial and research settings. The method focuses on measuring tensile strength normal to the surface, which provides a reliable comparison between similar types of thermal spray coatings.

Thermal spray coatings, which include materials such as ceramics (metal oxides or carbides) and metals, are widely used to enhance surface properties like wear, corrosion, and heat resistance. This standard supports manufacturers and users in ensuring consistent coating performance and reliability.

Key Topics

• Purpose and Use:

  • Quality control of thermal spray coatings
  • Acceptance testing for coated parts
  • Qualification of operators and procedures
  • Development and comparison of thermal spray materials

• Test Method Summary:

  • Involves coating a substrate fixture, bonding it to a loading fixture, and applying a tensile load perpendicular to the coated surface
  • Measures where the failure occurs: coating-substrate interface (adhesion), within the coating (cohesion), or in the bonding agent

• Applicable Coating Processes:

  • Combustion flame spraying
  • Plasma arc spraying
  • Two-wire arc spraying
  • High-velocity oxygen fuel spraying
  • Detonation processes

• Material Considerations:

  • Coating materials: ceramics, metals, carbides, or composites
  • Substrate materials: typically metals, occasionally ceramics such as oxides or graphite

• Limitations and Conditions:

  • Recommended for coatings at thicknesses above 0.015 in. (0.38 mm) to avoid adhesive penetration
  • Normally performed at ambient temperature, with adaptability for special requirements such as cryogenic testing
  • Not intended to directly predict service performance under operational or complex loading conditions

Applications

The ASTM C633-13(2021) test method is critical for a range of industries employing thermal spray coatings, including:

• Aerospace and Turbine Manufacturing: Ensures quality and durability of thermal barrier and wear-resistant coatings on engine components.

• Heavy Equipment and Automotive: Evaluates surface protection for parts exposed to abrasion, corrosion, or high temperatures.

• Energy Generation: Assesses performance of coatings for turbines, boilers, and other high-stress applications.

• Research and Development: Facilitates the comparison of new coating compositions, application techniques, and process improvements.

• Quality Assurance and Certification: Used for batch acceptance testing and validation of coating procedures and equipment, supporting compliance with industry standards.

By providing a consistent method to measure adhesion or cohesion strength, this standard helps reduce variability and enhances the reliability of coated products.

Related Standards

For comprehensive quality assurance and compatibility with other testing practices, the following ASTM standards are often referenced or used alongside ASTM C633:

• ASTM E4 – Practices for Force Calibration and Verification of Testing Machines: Ensures that the tensile testing machinery used meets specified accuracy and calibration requirements.

• Other Thermal Spray Coating Standards: Consider referencing additional ASTM and ISO documents relating to thermal spray process qualification, coating characterization, and other mechanical property assessments.

Consult the ASTM catalog for the most up-to-date list of related standards and further guidance on testing and quality management for thermal spray coatings.

Keywords: ASTM C633-13(2021), thermal spray coatings, adhesion strength, cohesion strength, tensile test method, industrial coating quality control, ASTM standard, coating qualification, ceramic coatings, metal coatings