Aviation products are often affected by extreme conditions such as high temperature, high speed, and high pressure during flight, so coatings with excellent wear resistance are needed to protect their surfaces. This article aims to discuss the technical requirements, inspection methods and acceptance rules of thermal spray wear-resistant coatings, and is applicable to the quality inspection of thermal spray wear-resistant coatings for aviation products. References are made to standards such as GB11374, HB6738, HB5476 and HB5486 to ensure the scientificity and accuracy of the inspection methods.
skills requirement
Thermal spray wear-resistant coatings need to meet multiple requirements such as appearance, thickness, hardness, bonding strength, porosity and microstructure.
Appearance: The coating surface should be smooth and even, without cracks, peeling or delamination.
Thickness: The coating thickness should meet the design requirements, within the range of 0.15~0.30mm.
Hardness, bonding strength, porosity: need to meet the specific index requirements specified in Table 1.
Microstructure: The microstructure of the coating should be uniform, and no cracks or separation of the coating from the substrate should occur.
Testing method
Methods involving appearance inspection, thickness measurement, hardness measurement, bonding strength testing, porosity determination and microstructure inspection.
Appearance: Use visual inspection method, illumination shall not be less than 300lx, use magnifying glass if necessary.
Thickness, hardness, and bonding strength: tested according to the methods specified in GB11374, HB5486, and HB5476 respectively.
Porosity: It can be measured by metallographic picture comparison method, metallographic grid measurement method or quantitative metallographic method.
Microstructure: By preparing metallographic samples and conducting microscopic observations, compare the actual situation with standard pictures.
Acceptance rules
Corresponding acceptance rules have been formulated for appearance, thickness, hardness, bonding strength, porosity, microstructure, etc. The appearance is 100% inspected to ensure that the appearance of the coating meets the requirements. Thickness, hardness, bonding strength, and porosity are checked before production and must meet the requirements.
Microstructure also needs to be inspected before or during production to ensure compliance with standards. Through the above technical requirements, inspection methods and acceptance rules, the performance of thermal spray wear-resistant coatings can be effectively evaluated to ensure that product quality meets requirements and improve product reliability and service life.
