某型航空发动机润滑油热衰变结构组成分析

利用高温反应釜与傅立叶红外光谱(FTIR)、气相色谱/质谱联用(GC/MS)技术,从分子水平分析添加有抗氧剂N-苯基-α-萘胺(T531)的聚α-烯烃(PAO)航空润滑基础油高温衰变,考察该润滑油的热安定性能.结果显示:低于200℃时,T531具有优良的抗氧化作用,能够较好地延缓基础油的高温衰变,但温度超过270℃后,T531的抗氧化性能降低,无法有效保护基础油.300℃高温产物经GC/MS分析,共检测到63种化合物,包括36种烷烃类化合物、25种烯烃类化合物、1种酮类化合物和抗氧剂T531,短链烷烃和烯烃的相对含量分别为5.835%和2.32%,是200℃高温时的20多倍,直接导致润滑油黏度的降低.在200℃高温反应油样中的T531相对含量仅为0.734%,远低于170℃和300℃反应后的2.019%和1.587%.可见,T531在200℃环境中消耗剧烈,对润滑基础油分子的抗氧化保护作用十分显著.

Analyzing Compounds in a Type of Aviation Lubricating Oils under Thermal Conditions

Poly-α-olefins(PAO)aviation lubricating base fluids with N-phenyl-alpha-naphthylamine(T531)were carried in high temperature autoclave to stimulate the conditions of aero-engine,and the differences in products' components at the molecular level were analyzed by gas chromatography/mass spectrometry(GC/MS)to investigate anti-oxidant influence on the thermal stability of PAO.The results revealed that T531 is helpful to exhibit better oxidation resistant effect in PAO below200 ℃.However,oil samples above 270 ℃ were pyrolysed drastically.And 63 kinds of compounds were detected by GC/MS in 300℃ oil samples,including 36 kinds of alkanes,25 kinds of alkenes,one kind of ketones and T531.The relative content of short-chain alkanes and alkenes increased to 5.835%and 2.32%respectively,20 times higher than that of 200℃,which led to the decrease of viscosity.In addition,the relative content of T531 dropt to 0.734%,lower than 2.019% in 170 ℃ and1.587%in 300 ℃.It was evident that T531 depleted dramatically and played an important role in preventing the lubricant from degradation.