Tribological Behavior of Advanced Base Oil and Grease for Space Applications

航天用高级基础油和润滑脂中的轴承疲劳寿命试验1。L_<10>life试验结果表明：601 EF润滑脂与815 Z基础油的寿命最长，其次是2001 A基础油，最后是R2000润滑脂与2001 A基础油的寿命最长，最后是815 Z基础油。在油815 Z的情况下，轴承寿命几乎不与膜参数A相关，与矿物油相反，矿物油显示出轴承寿命随着A的增加而增加的一般特征。815 Z油中含有缩醛基（-OCF_2O-），在高剪切速率下，油分子在机械剪切作用下发生的分解与氟化氢的分解是伴随缩醛基的分解而发生的。结果表明，高压下的永久性粘度损失和氟化氢的产生使815 Z油的轴承寿命缩短.在润滑脂601 EF与基础油815 Z的情况下，因此不会发生粘度损失的球轴承和延长轴承寿命。5.在相同的A条件下，边界润滑时摩擦系数较低的601 EF、2001 A和R2000润滑脂的使用寿命比石蜡基矿物基础油长。空间PFPE润滑剂在弹流润滑条件下的粘度损失1。在弹流润滑条件下，815 Z流体发生了粘度损失。永久性粘度损失和暂时性粘度损失的区别.在平均接触压力为1.95 ~ 2.67GPa范围内，815 Z流体的永久粘度随时间迅速下降。随着平均接触压力的减小，粘度损失程度逐渐减小.该流体中含有缩醛基团（-OCF_2O-），在高压条件下分子分解导致永久性粘度损失.粘度损失随相态由液态向弹塑性固态的转变而增大.在弹流试验的入口区域，815 Z流体表现出短暂的粘度损失，且膜厚较低。

Bearing Fatigue Life Tests in Advanced Base Oil and Grease for Space Applications1. The results of L_<10> life tests showed a long life in order of grease 601EF with base oil 815Z, base oil 2001A, grease R2000 with base oil 2001A and base oil 815Z.2. In the case of oil 815Z, bearing life is hardly related to film parameter A, in contrast to mineral oils, which show a general feature that bearing life increases with increasing A.3. Oil 815Z, having the acetal group (-OCF_2O-), at high shear rate in EHL conjunction the decomposition of oil molecule occurred by mechanical shear and hydrogen fluoride is occurred with the decomposition of acetal group. As a result, the permanent viscosity loss at high Hertzian pressure and hydrogen fluoride generation made shorten bearing life of 815Z oil.4. In the case of grease 601EF with base oil 815Z, thus viscosity loss doesn't occur in ball bearings and lengthen bearings life.5. Under the same A condition, grease 601EF, oil 2001A and grease R2000 with the lower friction coefficient under boundary lubrication has the longer life than paraffinic mineral base oil.Viscosity Loss in PFPE Lubricant for Space Applications under EHL conditions1. The viscosity loss occurred in 815Z fluid under EHL conditions. Permanent viscosity loss and temporary viscosity loss are observed.2. Permanent viscosity loss of 815Z fluid occurred rapidly with time at mean contact pressure of 1.95 GPa to 2.67 GPa. When mean contact pressure decreased, degree of viscosity loss decreased gradually.3. The fluid contains acetal group (-OCF_2O-), which the cause of permanent viscosity loss by decomposition of molecule under the high-pressure conditions.4. Viscosity loss increases with the change of phase from liquid to elastic-plastic solid.5. In the inlet region of EHL test, 815Z fluid showed temporary viscosity loss with lower film thickness.