11/8/23 CHAPTER 17: CORROSION and DEGRADATION of MATERIALS ISSUES TO ADDRESS ... > Why and how does corrosion occur? > Which metals are most likely to corrode? > How do temperature and the environment affect corrosion rate? > How do polymers degrade? > How can we prevent and/or control corrosion? Chapter 17 - 1 1 ANNOUNCEMENTS - 1 • Reading: Chapter 17, all sections except 17.4, 17.10 • Week 8 Recitations: > No Quiz ... Midterm 2, 11/14/23, 8:00-8:50 am > Chapter 17 H/W Problems: 17.2, 17.5, 17.7, 17.12 >Recitation Problems: As announced in recitation Chapter 17 - 2 2 1
11/8/23 ANNOUNCEMENTS - 2 . Midterm #2: Week 8: Tuesday, 11/14/23, 8:00-8:50 am Ø Main Auditorium - most of the class Ø ODR Accommodations - ODR Test Proctoring Center Coverage: Chapters 5, 6, 12, 14, plus a smattering from Chapters 1, 2, 3 & 4. Concepts from earlier chapters can carry over to later material ... § Read textbook, review lecture notes ... learn definitions; understand diffusion mechanisms, mechanical properties, ceramic structures & density, polymers, etc. § Review Example Problems in textbook & recitation problem solutions ... understand concepts and how problems are solved .practice, practice, practice ... · Exam Prep: Ø Make use of TA, RI office hours Ø Consult ACE tutors ... ask Qs. Chapter 17 - 3 3 ANNOUNCEMENTS - 3 (Final Exam) · Final Exam: >Tuesday, December 12, 10:30-12:30: Ø Main Auditorium for most of the class Ø ODR Accommodations: - ODR Test Proctoring Center Ø Coverage: Cumulative, with an emphasis on material covered since Midterm 2. Ø Part of 1 Q will be a "Bonus" question ... so >100% possible. Ø No early exams for personal convenience ... term is not over until the end of Finals Week ... · More than 3 Exams on same day? Ø See Provost's Office policy ... Ø https://drexel.edu/registrar/scheduling/exams/exam-policy/ Ø Request for relief must be made to the Provost's Office at least three (3) days before the examination date Ø Fall & Spring, courses with higher numbers give early exams Chapter 17 - 4 4 2
11/8/23 INTRODUCTION Background: > Most materials will, and do, interact with their environment > Such interactions often result in deterioration of their mechanical or other properties: - Impairs the usefulness of materials ... > Consequences of ignoring degradation? Deterioration Mechanisms: > Metals: - Loss of material via dissolution (corrosion) - Formation of oxide scales/films which may later flake off (oxidation) > Ceramics: - Relatively deterioration-resistant ... why? Many already oxidized! - Issue mainly at high temps & in very extreme (e.g., hot) environments > Polymers: - Degradation ... - Dissolve in some solvents ... absorb & swell - UV & other radiation, heat, etc. can break covalent bonds Chapter 17 - 5 5 CORROSION - Examples Chapter 17 - 6 6 3