GB/T 44335-2024 specifies a test method for determining the internal stress in fine ceramic coatings based on the Stoney formula, applicable to single-side coated specimens where the coating-to-substrate thickness ratio is less than 10% and deformation is elastic. The core principle of the standard involves calculating the internal stress in the coating by measuring the curvature change of the substrate induced by the coating, combined with parameters such as the substrate's elastic modulus and Poisson's ratio. The test requires the use of an optical profiler or a contact stylus profiler (with a curvature radius resolution ≤5 μm) to measure curvature, along with instruments such as thickness gauges and high-precision calipers to obtain dimensional data. This standard provides a unified technical basis for the research and development, quality control, and application reliability assessment of fine ceramic coatings.