Preparation And Application Of Superhydrophobic Coating On Metal Tube Surface Of Temperature Sensor

Hexamethylol melamine is an important raw material for resins.During the synthesis of hexamethylol melamine,the intermediate product low methylol melamine is easily adsorbed on the surface of metal tube of the temperature sensor,resulting in a large amount of hydroxymethyl melamine adhering to the surface,hindering the temperature sensor's response to temperature changes in the reaction kettle and affecting the control of process parameters.In this regard,the experiment takes the mild steel tube as the object,carries out the research on the surface superhydrophobic coating preparation technology,and analyzes the temperature response performance change of the temperature sensor containing the superhydrophobic coating using the hexamethylol melamine synthesis reactor for 7 days Changes.The research results play an important role in improving the yield of hexamethylol melamine products and improving the product quality.The main research results include:(1)For mild steel,the chemical etching process is optimized by single factor experiment and orthogonal experiment.The etchant is composed of 11%HF and 9%HNO₃.When the etching temperature is 26?and the etching time is 8min,the etching effect is the best,and the contact angle reached 83.5°.(2)The preparation and properties of stearic acid superhydrophobic coating were studied.The mild steel is treated with 12.0 mmol/L stearic acid ethanol solution for self-assembly,and the self-assembly process conditions are optimized by single factor experiment and orthogonal experiment.When the temperature is 32?and the modification is modified for 60 min,the contact angle reached 158.3°.(3)The superhydrophobic coating on the surface of mild steel shows good stability,corrosion resistance and high hardness.When placed at room temperature for 60 days,the contact angle only decreased by 1.0°.In 3.5%Na Cl solution,Ecorr increased from-138 m V before coating to-107 m V,and Icorr decreased by two orders of magnitude.(4)The metal tube of the temperature sensor with superhydrophobic coating is immersed into the hexamethylol melamine synthesis reactor,and study the temperature response performance of the temperature sensor with superhydrophobic coating after one week of use.The initial test deviation of the superhydrophobic coating temperature sensor and the standard thermometer is 0.76%,and the deviation of the two temperature sensors after one week of use is 3.12%.Meanwhile,and there is only a small amount of white attachments on the surface of the super-hydrophobic temperature sensor.