Composition of a Ceramic-Bonded Film

Apart from the three major components of the bonded film, the binder, the molybdenum disulphide, and the solvent or dispersant, many other substances may be incorporated, and several have already been mentioned. 

The mechanism of action of antimony trioxide has been discussed in some detail in Chapter 7. It has been widely used in bonded film formulations since the mid-nineteen-sixties to improve the wear life of coatings. The greatest improvement is obtained at higher temperatures, and Kinner found a small deterioration in performance at low temperatures when antimony trioxide was used. He also found that the use of lead oxide, PbO, together with antimony trioxide gave markedly improved performance at both high and low temperatures. 

Lavik et al ° reported up to 400% improvement in wear life, and lower friction at high or low temperature, when antimony trioxide was used in polyimide or polybenzothiazole-bonded films. Lower improvements, up to 270%, were obtained with antimony trisulphide, while Bartz reported that the addition of both graphite and antimony tetrasulphide (or antimony thio-antimonate Sb(SbS4)) gave a much greater improvement in the life of a polybutyltitanate-bonded molybdenum disulphide film than either of the additives separately. 

A number of different metals have been used in powder form as additives to bonded molybdenum disulphide films. They include gold, silver, nickel and tantalum, and it has been suggested that they improve film life by helping to facilitate readhesion of lubricant debris to the substrate. Many other components have been added to bonded films as corrosion inhibitors, anti-oxidants, dispersion stabilisers and biocides, and many different solvents have been used. There is therefore an almost infinite variety of possible formulations, and several hundred have been produced commercially. 

The object of surface preparation is to obtain the best performance and life of a bonded film for a reasonable expenditure of effort. In general bonded films will adhere to almost any surface which is clean and free of grease, oil and other 

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