| This topic aims to use organic gluing method,choose MoS2 and PTFE as solid lubricating materials,PAI as binder,to develop a new type of coating to replace the use of thread compound on the tube connections,and research the coating’s composition,preparation techniques and anti-galling performance.The main results as follows:(1)The mixed solvent used to disperse coatings can be confected NMP with DMF、ethyl acetate、xylene and it has good volatile gradient,the best ratio is 4:4:1:1.(2)The MoS2 powder was modified with surface modification technology to prevent settlement,KH-570 is the best modifier and it can reinforced the adhesive of coating and the base.(3)Phosphating treatment can help to increase the bonding force.(4)The PTFE particles were gathered on the surface of the film and obtained a self-stratifying coating.(5)Two-step method to dry can obtain an excellent coating,the spayed coating first at 70-80℃ for 20 minutes,then heated to 280-300℃to melt and curing.(6)The added of PTFE would reduce the friction coefficient and the lowest level was 0.034.(7)When the ratio of MoS2:PAI more than 1.5,the bonding strength decreased and brittleness increased,easy to crackle and flake off.When PAI:MoS2:PTFE =6:3:1,the coating has a best comprehensive performance.(8)The PAI-MoS2-PTFE coating may pass six months atmospheric exposure test and 72 hours Neutral salt spray test without any change.(9)Threading and unthreading tests are performed,the PAI-MoS2-PTFE coating could pass nine times Threading and unthreading tests without thread and flake off. |
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