Dispersion stability of nano-tungsten disulfide particulates

Transcription

1 41 2 ( ) Vol.41 No Journal of Central South University (Science and Technology) Apr ( ) TF123.7 TH117.2 A (2010) Dispersion stability of nano-tungsten disulfide particulates SHI Chen 1, MAO Da-heng 1, MAO Xiang-hui 2 (1. School of Mechanical and Electrical Engineering, Central South University, Changsha , China; 2. Changsha Shengda Lube Science and Technology Co.Ltd, Changsha , China) Abstract: In order to improve the dispersion stability of nano-tungsten disulfide in lubricating oil, nano-tungsten disulfide particulates were treated by the combinative method of ultrasonic dispersion, mechanical agitation and surface modification, the settlement speeds, size distributions and microscope pictures of particulates in oil were tested to evaluate the dispersion effect, and dispersion principle of nano-tungsten disulfide in lubricating oil was studied through the analysis of titration and infra-red spectrum. Finally, the repair action of nano-tungsten disulfide to abrasive surfaces was studied. The results show that affected by ultrasonic and mechanical agitation, surface modified nano-tungsten disulfide particulates don t form big glomeration and disperse in the lubricating oil evenly and stably. Meanwhile, surface modifier can react with hydroxide radicals on surfaces of nano-tungsten disulfide particulates, making particulates surfaces adsorb many lipophilic groups with long chains, which can stretch in the oil adequately and form steric hindrance layers that stop particulates from conglomerating and depositing, leading to nano-tungsten disulfide particulates stable dispersion in lubricating oil. And moreover, the nano-tungsten disulfide particulates which disperse in the lubricating oil stably can form effectual protective films on abrasive surfaces in the course of friction and repair the abrasive surfaces well. Key words: nano-tungsten disulfide; dispersion stability; dispersion principle ( 973 ) (2007CB613706) (07MX02) ( ) (1982 ) shichenmail@163.com

2 MPa [1 2] [3 4] PetrolMoly PetrolMoly 125 [5 6] [7 8] [9] 2 [10 11] [13] nm 1(c) 1(c) 1 S-W-S (SEM) [12] (a) (b) (c) 1 Fig.1 Microcosmic appearance of tungsten disulfide particulates

3 478 ( ) [14] [15] ( 20 khz 200 W) Fig.3 Three-dimensional sketch map of ultrasonic dispersing equipment Fig.2 Infra-red spectrogram of surface modifier Table 1 Performance parameters of base oil / / / /(kg m 3 ) /(mm 2 s 1 )

4 ~ Fig.5 Variation of mean diameter and stabilizing time of particulates in base oil with treating time 4 Fig.4 Variation of stabilizing time of particulates in base oil with surface modifier s content µm 5.5 h 1 µm [16] 6 6 (a) (b) (c) 6 Fig.6 Dispersing situation of nano-tungsten disulfide in base oil

5 480 ( 6(c)) 2.4 [10] 2 2 NaOH NaOH cm cm cm cm 1 2 Table 2 Density contrast of hydroxide radicals on nano-tungsten disulfide particulates surfaces / ( nm 2 ) ( ) NaOH ( ) 1.58 NaOH ( ) 0.05 NaOH Fig.7 Infra-red spectrogram of nano-tungsten disulfide N r/min 10 min N 9 9

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