Tham khảo tài liệu 'compressor instability with integral methods episode 2 part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Chapter 8 Surface Quality Aspects Surface Quality Features Quality features of substrate surfaces determine the performance and properties of applied coating systems. Related to the performance of corrosion protective coating systems ISO series 8502 states the following The performance of protective coatings of paint and related products applied to steel is significantly affected by the state of the steel surface immediately prior to painting. The principal factors to influence this performance are 1 the presence of rust and mill scale 2 the presence of surface contaminants including salts dust oil and greases 3 the surface profile. Numerous regulative standards are issued to define these factors and testing methods are available to quantify them. Blast cleaned surfaces show some distinct features and extensive experimental studies were performed to address this special point often in direct comparison to other surface preparation methods. Figure shows a scanning electron microscope image of a steel substrate after blast cleaning. A general distinction can be made between primary and secondary substrate surface features. Primary surface features may include those properties which are part of coating specifications. They include the following features visual cleanliness chemical cleanliness physical cleanliness profile properties surface integrity. Secondary surface features may include properties which are determined by and depend on primary features. They may include the following features surface energy wettability adhesion of coating to substrate. A. Momber Blast Cleaning Technology Springer 2008 337 338 8 Surface Quality Aspects Fig. Morphology of a blast cleaned low-carbon steel substrate. Parameters p MPa dN 8 mm tp 90 abrasive aluminium oxide mp 19 g s dP 165 pm Photograph author Visual Cleanliness Visual Standards A number of regulatory standards have been developed in order to define and to characterise steel surfaces prepared .
