Cameron-Plint

A Cameron-Plint friction machine generated tribofilms with two-layer structure a zinc polyphosphate thermal film overlying a mixed short-chain phosphate glass, containing iron sulfide precipitates. A tribochemical reaction between the zinc polyphosphate and the iron oxides species is proposed on the basis of the hard and soft acid and base HSAB principle (Martin, 1999 Martin et al., 2001). 

Friction coefficients determined via the pin-on-disc or the more modern technique of Cameron-Plint machine depend on the friction between two smooth surfaces. The typical surface roughness is about 10-15 tim, and such techniques investigate friction modification as a function of ... 

A new type of calcium detergent chemistry has been described which has inbuilt friction modification [1]. Using an oscillating Cameron-Plint tribometer, this new class of additive lowers the friction coefficient of finished lubricating... 

Reply by Professor A Cameron (Cameron-Plint Ltd., Cambridge). 

Figure 1. Schematic representation of the different steps in the sample preparation a) generation of the tribofilm (Cameron-Plint tester, friction zone dimensions 6x8 mm), b) positioning the altuninum mask (stripes of 1mm width), c) Ar ion etching, d) removal of the mask.

In this section, the DZFT test is performed in the base oil (PA06), the same one as used for the tribofilm generation in the Cameron-Plint machine. This situation corresponds to a particular case, when all active additives have been depleted. The DZFT is run on the sample under the following conditions stroke length 2.0 mm (2.4 mm in 5.1 and 5.2), maximum Hertzian pressure 0.5 GPa, 500 cycles in ambient air. Figure 6. shows friction (Figure 6.a) and ECR (Figure 6.b) results. The tribofilm is located at the top of the pictures and the etched zone at the bottom. 

At the end of the experiment, the ECR measurement can no longer detect the film. Maybe, this difference is due to the hi roughness of the sample (some scratches of the Cameron-Plint track). The tribofilm covdd be present in the valleys but not on the tops. That could be the reason why, this film is detected in Auger but not in ECR measurements. 

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