ASTM C664 is the ASTM standard for the Standard Test Methods for Thickness of Diffusion Coating, providing a technical basis for measuring coating thickness in a controlled and repeatable way. It is used to support consistent evaluation of diffusion coatings where thickness is an important quality attribute. By defining test methods for this measurement, the standard helps laboratories, manufacturers, and purchasers compare results more reliably and maintain better control over product acceptance and performance.

Purpose of ASTM C664

The purpose of ASTM C664 is to establish standardized test methods for determining the thickness of diffusion coating. Because coating thickness can affect service behavior, process control, and acceptance decisions, a clear and repeatable method is important. This standard gives users a common reference for measurement practices, helping reduce variation between test results and supporting more consistent technical communication. It is especially useful when thickness data must be evaluated for quality assurance or specification compliance.

Common use cases of ASTM C664

ASTM C664 is commonly used in testing and inspection workflows where diffusion coatings must be measured and verified. It may support laboratory evaluation, incoming inspection, production quality control, and product qualification programs. The standard is relevant wherever thickness data is needed to confirm that a coated part or material meets a required level of consistency. In practice, it helps organizations apply a shared method when comparing results across batches, facilities, or testing teams.

Why ASTM C664 matters

This standard matters because thickness measurement is a key part of reliable coating evaluation. Using ASTM C664 can help improve consistency in test reporting, reduce ambiguity during procurement or acceptance, and support better quality control decisions. For technical teams, it provides a recognized framework for comparing results and documenting compliance-related measurements. That can lower the risk of disputes and help ensure diffusion coatings are assessed using a common and defensible method.

• Standardized thickness measurement
• Diffusion coating evaluation
• Quality control support
• Test result consistency
• Compliance-focused verification