Synthesis and characterization of molybdenum disulphide formed from ammonium tetrathiomolybdate

被引:81
作者
Wang, HW
Skeldon, P
Thompson, GE
Wood, GC
机构
[1] Corrosion and Protection Centre, University of Manchester, Institute of Science and Technology, Manchester M60 1QD
基金
英国工程与自然科学研究理事会;
关键词
D O I
10.1023/A:1018538424373
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
An investigation has been carried out into the possibility of in situ formation of MoS2 within porous anodic films on aluminium, to improve subsequent tribological behaviour, by re-anodizing in thiomolybdate electrolyte. Acidification of thiomolybdate was employed to simulate the conditions for formation of the sulphide at the anodic film/electrolyte interface, followed by appropriate vacuum heat treatments to study possible temperature effects on the sulphide due to either friction or Joule heating during anodizing. The products of both acidification and heat treatment, characterized by X-ray powder diffraction and scanning electron microscopy, were compared with those formed by direct thermal decomposition of ammonium tetrathiomolybdate crystals. The precipitate formed by acidification was mainly amorphous molybdenum trisulphide (MoS3), which on heat treatment at 450 and 850 degrees C yielded 3R-MoS2. 3R-MoS2 also formed by the thermal decomposition of thiomolybdate crystals. Thermogravimetric and differential thermal analyses showed that the decomposition of MoS3 to MoS2 occurred in the range 220-370 degrees C and revealed the sequence of reaction steps. The findings suggest that mainly amorphous MoS3 is formed as a consequence of changes in the pH of the film/electrolyte interface during re-anodizing but the product is relatively easily transformed to crystalline MoS2 on moderate heating which may occur during wear processes.
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页码:497 / 502
页数:6
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