Wear and Corrosion

Materials – the basis in materials science and engineering.

The main contents are transmitted at theory classes used expositive techniques, as PowerPoint support, to developing skills through lectures accomplished with discussions. The iterative applications as the exercises resolution are conformed on theoretical-practical lectures. Practical classes, main to developing practical skills, through lectures with individual or group discussions, consist in experimental methods applications with students hand care, that aloud the sedimentation on wear and on corrosion theoretical fundaments and concepts and theoretical-practical bases.

The main objective of this course unit is related with learning outcomes and competences that allowed to understand, measure and control the ways of wear and corrosion phenomena’s in materials as degradation and destructive process of mechanical components and systems.

Upon completion of this unit, others transversal competences are developed, providing that the students should be able to use laboratory techniques and equipments in tribological studies, as well to be able to make reasonable scientific evaluation of related experimental results.

Understand the corrosion principles and common corrosion forms; Be aware of methods used to mitigate and prevent corrosion.

Part I – Wear

Introduction to tribology: significance, origins and objectives; economic impact.

Friction and wear: friction fundamentals; surface effects in tribology – adsorption, surface topography, measurement of surface roughness; friction models; friction values and friction influent parameters; energy dissipation by friction; wear mechanisms; wear laws; wear influent parameters; wear maps.

Materials for tribological applications: tribological and metallurgical compatibility; conventional and novel materials; surface preparation techniques for tribological applications; coatings and surface treatments.

Lubrication and lubricants: lubrication significance and objectives; lubrication regimes; dry or solid lubrication; self lubrication; lubricant types and application; lubricant oils proprieties; viscosity; mineral oils; synthetic oils; lubricant additives; solid lubricants and coatings; gaseous lubricants; greases; transportation and lubricants applications.

Mechanical components for tribological applications: bearings – journal and thrust bearings, plain and rolling bearings; seals – static, dynamic, pseudo-static.

Lubrication systems and components lubrication: plain and rolling bearings lubrication; gears and roller chain lubrication; turbines and motors lubrication.

Tribological tests – equipments and methods; standard tests; applications.

Part II – Corrosion

Introduction to corrosion: definition; classification; corrosive environments; corrosion damage; corrosion costs; corrosion engineering. Electrochemical fundamentals of corrosion: electrochemical reactions; standard electrode potentials; Nernst equation; electrochemical cells.

Corrosion kinetics: corrosion rate units; Fraday’s law; polarisation; passivation; effect of environmental variables on the corrosion rate. Pourbaix diagrams.

Types of corrosion: uniform corrosion; galvanic corrosion; crevice corrosion; pitting corrosion; intergranular corrosion; selective corrosion; erosion corrosion; stress corrosion.

Corrosion prevention: materials selection; modification of environment; design; metallic coatings; non-metallic inorganic coatings; organic coatings; cathodic and anodic protection. High temperature corrosion: high temperature oxidation – protective oxide films, mechanisms of oxidation, oxidation kinetics, resistance of metals to oxidation; other mechanisms of high temperature corrosion.

Evaluation Method

Final written exam (75.0%); laboratory work or a case-study presented by written report or by oral presentation with discussion at wear (12.5%), and, at corrosion, practical written exam (12.5%) done until the realization of the first evaluation – until the same moment of the called “exame normal” at the respective ISEC official Portuguese list map. At wear, depending on the number of students by year, that compromises the limit of the conditioned level of practical work at laboratory plant, or in other force majeure and in exception, it will be possible the same situation - practical written question at the final exam instead of laboratory or case-study reports - and not doing the students directly and individually this laboratory practice, but watching the overall execution of the same, or only being taught the experimental technique if there is any casual unavailability of any laboratory equipment. To Erasmus student’s progress assessment can be established by lectures as complementary meetings in English language, to develop parallel written project work in a predefined subject, with individual final presentation and discussion, complementing or replacing the final written test, whether in wear or corrosion, depending on the respective teacher.

Conditions for Exam Admission

According to general rules used in the school.

Access Conditions and Attendance Excuse

It’s necessary presence at 75% of practical classes. The students with positive classification on the last year at those practical examination parts, are dispensed of this presences.

Conditions for Results Improvement

Improving grades or retaking exams is allowed, according to general rules of the course and used in the school.

NAO