GB/Z 45463-2025 "Determination of thermal spray-on lining porosity" is an important guiding standard in the field of thermal spray-on lining detection. The standard specifies the applicable types of thermal spray-on lining, elaborates the determination principle in detail, and standardizes the requirements of instruments and equipment, the preparation process of samples and specific test operation steps. At the same time, strict regulations are made on key links such as porosity calculation and data processing, and the influencing factors of test results are explained. The release of this standard provides a scientific basis for accurate determination of thermal spray-on lining porosity, evaluation of coating mass and optimization of process.