Tribological Performance of Silahydrocarbons Used as Steel-Steel Lubricants under Vacuum and Atmospheric Pressure

Hai-Zhong Wang,Dan Qiao,Song-Wei Zhang,Wei-Min Liu,Da-Peng Feng

doi:10.1155/2014/852386

Abstract

The silahydrocarbons of tetraalkylsilanes with different substituted alkyl groups (named as SiCH) were synthesized and evaluated as lubricants for steel-steel contacts by a home-made vacuum four-ball tribometer (VFBT-4000) under atmospheric pressure and under vacuum pressure (5×10-4 Pa). The SiCH oils possess better thermal stability, low temperature fluidity, and lower saturated vapor pressure than those of multialkylatedcyclopentanes (MACs). The tribological performances of the SiCH oils are also superior to those of MACs and PFPE-Z25 in terms of friction-reduction ability and antiwear capacity under sliding friction at vacuum. The SEM/EDS and XPS results reveal that the boundary lubricating film consisting of(-O-Si-R-)ncompounds is formed by tribochemical reactions and serious adhesion wear under atmospheric pressure and the film consisting of(-Si-R-Si-)ncompounds is formed on the worn surface under vacuum pressure.

Highlights

The use of space satellites for communication, navigation, and defense is becoming more and more important
The findings of SiCH-3 are shown as follows [infrared spectroscopy (IR) (KBr film), ]max/cm−1, Figure 3(a)]: C–H stretching vibration bands appear at 2956 cm−1, 2921 cm−1, and 2853 cm−1; C–H band modes at 1466 cm−1 and 1378 cm−1, and the band at 720 cm−1 is the–(CH2)7–rocking vibration; Si–C
The tribochemical reactions of the SiCH oils with the steel surface are different under atmospheric pressure and the vacuum pressure; different boundary films might be formed during the sliding friction under different conditions

Summary

Introduction

The use of space satellites for communication, navigation, and defense is becoming more and more important. High costs for both construction and launch satellites are driving the need to extend the service life of these satellites from the current 5 to 8 years to 10 years and even for a longer period. The improvement of lubrication and antiwear performance for the mechanical systems is the key to extend the service life of satellites and spacecrafts. The majority of current aerospace applications use mineral oils, perfluoropolyalkylethers (PFPEs), or synthetic hydrocarbons, such as multialkylatedcyclopentanes (MACs) and polyalphaolefins (PAO) [9, 10]. MACs and PAO are of limited use at low temperature and in vacuum

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Conclusion