4. Conclusion

The analysis of surface deterioration in engines should enable us to make a reliable diagnosis of its origins, and to propose remedies to combat it.

Of course, examination is not always easy, and the cause of wear is not always clear from the damage. In many cases, the motor has been running for some time after the wear phenomenon has appeared, and the surfaces have deteriorated to such an extent that it is no longer possible to detect the origin of the failure. Thus, two surfaces that have seized up may subsequently be the site of severe corrosive wear due to oil oxidation and thermal decomposition of additives under the effect of excessive interfacial heating, severe abrasion by adhesive wear particles and even metal decohesion with the formation of cavities through a combined mechanism of adhesion and thermal fatigue.

Very often, deteriorated...