老化对PTFE/PPS复合涂层的疏水和防结冰性能的影响

Effect of Aging on Hydrophobic and Anti-icing Properties of PTFE/PPS Composite Coatings

目的飞机表面涂层在服役过程中受到高温、太阳光辐射作用,容易引起微观结构的破坏,失去原有的性能。本文探究了老化对PTFE/PPS复合涂层疏水、防结冰性能的影响。方法利用一步喷涂法在TC4基体上制备出PTFE/PPS复合涂层,使用SEM和三维形貌仪进行表面形貌分析,利用傅里叶红外光谱仪以及XPS分析涂层元素组成,在对制得的PTFE/PPS复合涂层进行高温热老化(24、48、96 h)以及太阳辐射光老化(24、48、96 h)实验后,对其进行疏水防结冰性能测试。结果原始的PTFE/PPS复合涂层和经过24、48、72高温热老化后PTFE/PPS复合涂层的表面粗糙度分别为8.075μm、5.383μm、4.583μm、5.466μm,静态水接触角由139.70°降至132.36°、131.13°、130.36°,结冰时间由最初的346 s缩短至326 s、309 s、294 s,冰晶黏附力由最初的8.65 N增加至8.90 N、9.15 N、9.65 N。经过24、48、72 h太阳辐射光老化后,PTFE/PPS复合涂层的表面粗糙度分别为10.549μm、10.974μm、9.969μm,静态水接触角由139.70°降至135.83°、133.85°、129.97°,结冰时间由最初的346 s缩短为317 s、269 s、242 s,冰晶黏附力由最初的8.65 N增加至9.05 N、9.15 N、9.40 N。结论热老化和光老化虽然会使PTFE/PPS复合涂层的疏水、防结冰性能有所下降,但与基体相比仍能保持良好的疏水、防结冰性能。

The PTFE/PPS composite coating applied to the surface of aircraft can greatly improve the icing phenomenon on the surface of aircraft.However,the aircraft surface coating is subject to high temperature and solar radiation during service,which is easy to cause the damage of microstructure and lose the original performance.Therefore,the effect of aging on the hydrophobic and anti-icing properties of PTFE/PPS composite coatings was investigated.Aircraft engine fan blade material titanium alloy Ti-6Al-4V(TC4)raw material was selected,and the TC4 matrix was processed into a 25 mm×25 mm×3 mm bulk sample by electric discharge wire cutting,and the TC4 matrix was subject to thermal treatment.Quartz sand with particle size of 250~800μm was selected for sand blasting.According to the PTFE:PPS ratio of 45:55,PPS powder particles were added to the PTFE emulsion to obtain a 45%PTFE/PPS coating.The prepared mixed paint was fully mixed into the ANEST IWATA W-71 spray gun,the spray gun pressure was adjusted to 0.3 MPa,and the distance between the muzzle and the workpiece was 20 cm,so that the spray angle was maintained at 45°.After drying at 100℃for 10 min,the sprayed composite coating was placed in a box curing furnace for curing treatment,gradually heated to 370℃within 45 min,and then sintered at constant temperature for 20 min.After cooling in the air,a 45%PTFE/PPS composite coating was obtained.The morphology was characterized with a scanning electron microscopy(SEM)(MERLIN Compact,ZEISS).The 3D morphology of the original coating was measured and the surface roughness was calculated with a laser confocal microscope(Olympus OLS4100).A Fourier infrared spectroscopy(FT-IR)(PerkinElmer)was used to analyze the chemical composition and functional groups of the PTFE/PPS composite coating under different service conditions.The composition and chemical morphology of the elements were analyzed with an X-ray photoelectron spectroscopy(XPS)(Thermo SCIENTIFIC ESCALAB 250Xi).After thermal aging(24,48,96 h)and solar radiation optical aging(24,48,96 h)experiments,the hydrophobic and anti-icing properties of the PTFE/PPS composite coating were tested.PTFE/PPS composite coating was prepared on a TC4 substrate by one step spraying method.The surface roughness of the original PTFE/PPS composite coating and the PTFE/PPS composite coating after 24 h,48 h and 72 h of thermal aging was 8.075μm,5.383μm,4.583μm and 5.466μm,respectively.The static water contact angle was reduced from 139.70°to 132.36°,131.13°and 130.36°,and the icing time was shortened from the initial 346 s to 326 s,309 s and 294 s.The adhesion of ice crystals increased from the initial 8.65 N to 8.90 N,9.15 N,9.65 N.After 24 h,48 h and 72 h of solar radiation aging,the surface roughness of the PTFE/PPS composite coating was 10.549μm,10.974μm and 9.969μm,respectively,and the static water contact angle decreased from 139.70°to 135.83°,133.85°and 129.97°.The icing time was shortened from the initial 346 s to 317 s,269 s and 242 s.The adhesion of ice crystals increased from the initial 8.65 N to 9.05 N,9.15 N,9.40 N.Although thermal aging and photoaging will reduce the hydrophobic and anti-icing properties of PTFE/PPS composite coatings,it can still maintain good hydrophobic and anti-icing properties compared with the matrix.