摘要:

AbstractThe results of work intended to produce inexpensive, synthetic lubricants compatible with R‐134a using waste carboxylic acids C4‐C6as the base are presented in this paper.The suitability of the products synthesised was first evaluated considering their physical and chemical properties, and their thermostability determined by the standard Philipp test (sealed glass tube method). Two ester bases were then selected for further testing — a pentaerythritol esterified with C4‐C6monocarboxylic acids and a polyalkyleneglycol similarly esterified with monocarboxylic acids C4‐C6.The base oils chosen were tested for their corrosive action on metals in the presence of water in different concentrations. The pentaerythritol ester proved to have the most advantageous properties at that stage. The results of the laboratory tests have been corroborated by trials conducted on real refrigerating compressor systems. Only the lubricant that was obtained using pentaerythritol esterified with monocarboxylic acids C4‐C6as the base withstood the

ISSN:0265-6582    

DOI:10.1002/jsl.3000130402

出版商:John Wiley&Sons, Ltd    

年代:1997

数据来源: WILEY

摘要:

AbstractA significant amount of lubricating oils and greases can enter the environment, producing contamination of both soil and water. Over the last few years, pressure on lubricant producers and consumers has caused them to seek a solution involving less environmentally harmful lubricants. In Croatia, a significant quantity of lubricants is disposed of without control, polluting soil and water; as a result, lubricant producers have looked seriously at biodegradable lubricating oils and greases.This paper presents information on development of some biodegradable hydraulic oils and lubricating greases based on lithium and calcium soaps, using synthetic esters and rapeseed oil, and presents their physical and chemical properties, and their applications.

ISSN:0265-6582    

DOI:10.1002/jsl.3000130403

出版商:John Wiley&Sons, Ltd    

年代:1997

数据来源: WILEY

摘要:

AbstractIn many applications, such as marine industries, pumping of underground water, and in some chemical industries, sliding elements are lubricated with the process fluid (e.g. salt water). Therefore, the effect of salt water on the tribological behaviour of metallic friction couples has been a subject of study. In the present work, the influence of salt water solution (3 wt. % sodium chloride) on the tribological behaviour of some polymeric coatings is investigated, using a pin‐on‐disc testing machine, at different sliding speeds and normal loads. The coating consists of a base‐matrix of high‐density polyethylene (HDPE) and polyamide (PA6) with different concentrations of copper‐ and tin‐powder fillers. The effect of the formation of the oxide films, sodium hydroxide microlayers (NaOH) and the polymeric transformed films on the friction mechanism, is discussed. The results show that squeeze of the lubricant takes place in the presence of the NaCl‐solution; and, despite the relatively low viscosity of the lubricant, hydrodynamic pressure affected the friction mechanism at the sliding speed of 0.50 m/s, resulting in a significant reduction in the coefficient of friction. The value of the coefficient of friction seems also to be affected by the generation of sodium hydroxide, as well as the oxide films and material transfer layers. At a low speed (0.20 m/s), the PA6‐based composites with copper‐filler showed an optimal wear resistance at norma

ISSN:0265-6582    

DOI:10.1002/jsl.3000130404

出版商:John Wiley&Sons, Ltd    

年代:1997

数据来源: WILEY

摘要:

AbstractThe metal‐working industry is increasingly interested in synthetic metalworking fluids and coolants. The excellent lubricating properties of polyalkylene glycols have been recognised in areas such as gear lubricants, hydraulic fluids, and compressor lubricants. The main purpose of the present work was to investigate the friction and wear properties of several polyethylene glycols and their synergy with a common water‐soluble EP additive, using four‐ball and ball‐on‐plate tr

ISSN:0265-6582    

DOI:10.1002/jsl.3000130405

出版商:John Wiley&Sons, Ltd    

年代:1997

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000130406

出版商:John Wiley&Sons, Ltd    

年代:1997

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000130407

出版商:John Wiley&Sons, Ltd    

年代:1997

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000130408

出版商:John Wiley&Sons, Ltd    

年代:1997

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000130409

出版商:John Wiley&Sons, Ltd    

年代:1997

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000130401

出版商:John Wiley&Sons, Ltd    

年代:1997

数据来源: WILEY