Colloidal thiophosphorus calcium salt as antiwear additive
作者:
Bruno Delfort,
Maurice Born,
Bertrand Daoudal,
Agnes Chivé,
期刊:
Lubrication Science
(WILEY Available online 1996)
卷期:
Volume 8,
issue 2
页码: 129-143
ISSN:0954-0075
年代: 1996
DOI:10.1002/ls.3010080204
出版商: John Wiley&Sons, Ltd
关键词: colloidal calcium thiophosphate;synthesis;antiwear;additive;EP;thermal stability
数据来源: WILEY
摘要:
AbstractThis paper describes the synthesis of an oil‐soluble colloidal calcium thiophosphate by a direct route. It consists of the reaction of calcium oxide or hydroxide with tetraphosphorus decasulphide and water in the presence of a surfactant such as a calcium alkylaryl sulphonate in an organic medium. Reaction and micellisation occurred simultaneously according to a one‐step process. The product is characterised by a high calcium, phosphorus and sulphur content. The colloidal nature of the product has been confirmed by dialysis. The31P‐NMR spectrum showed signals characteristic of a blend of different calcium thiophosphates, plus calcium phosphate. The product could be defined as a core of different calcium (thio)phosphates surrounded by a calcium alkylaryl sulphonate shell, according to a reverse micelle type association in oil. This compound was evaluated as an antiwear additive in a 130 Neutral Solvent mineral oil by anti‐wear and extreme‐pressure four‐ball tests. The extreme‐pressure characteristics depend on the concentration of mineral colloidal core in oil. The antiwear properties are a function not only of the concentration, but also of the colloidal core/surfactant shell ratio. Thermogravimetric analysis of these colloidal species shows a weight loss in the 350°C to 450°C range, due to surfactant degradation. The further evolution of weight loss up to 900°C demonstrates the high thermal stability of the colloidal calcium (thi
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