Metals & Biomedical Applications

Question 1

Common metals used in biomedical appliations

Answer 1

Titanium, Stainless steel 316, Co-Cr-Mo. Also Au, Ag, Cu

Question 2

biometals are not bioactive

Answer 2

just bioinert and biocompatible within the span of a life time.

Question 3

Understand the basics of the « virtuous » triangle of Materials Science

Answer 3

Processing, performance, microstructure

Question 4

Biometals

Answer 4

Mg, Ti, Cr, Co, Ni, Cu

Question 5

Dental alloys

Answer 5

Silver, Gold, Tin, Mercury

Question 6

Bonds in metals

Answer 6

A network of positive ions and a moving sea of electrons. Metallic character: conductivity, shiny aspect, formability

Question 7

Normal metals

Answer 7

Al,Mg,Na: weak bonding

Question 8

Transition metals

Answer 8

(some covalent character due to unfilled internal electron shells): stronger bonds, higher densities and melting

Question 9

Crystallization

Answer 9

isothermal evolution with heat evolution

Question 10

Vitreous transition

Answer 10

gradual transition without heat evolution

Question 11

Are the solute atoms (ions) located on a periodic lattice?

Answer 11

Yes: ordered (substitutional) solid solutions. No: disordered (substitutional) solid solution.

Question 12

All structures contain defects, but it’s not always detrimental to performance

Answer 12

A classification of defects by extension:
• Point defects (0D),
• Linear defects (1D),
• Surface defects (2D),
• Volumic defects (3D)

Question 13

Types of defects

Answer 13

vacancies, self-interstitial, substitutional or intersitial solute atom (ion)

Question 14

For ionic defects

Answer 14

the electrical neutrality has to be ensured: two defects rather than on

Question 15

Impacts of point defects

Answer 15

Impact on transfer phenomena, matter transfer, electrical conduction

Question 16

Volumic defects

Answer 16

Pores & cavities, foreign particles, non-desired phases

Question 17

3D deffects

Answer 17

detrimental. concentrate stresses and may initiate cracking in metals, initiate corrosion

Question 18

The control of volumic defects is associated with

Answer 18

high additional cost. (high purity materials, controlled atmospheres, clean room processing)

Question 19

Thermodynamics of materials

Answer 19

–Limited to stable equilibrium situations (time is not a variable), but metastable equilibrium may be considered,
–Chemical thermodynamics, solutions, reactions…
–difficulty in defining simplified system to represent a complex reality
–Numerical models are available, or diagrams

Question 20

Solid state reaction kinetics

Answer 20

Time is the main variable to describe the evolution of a system:
•Nucleation (surface phenomena),
•Growth limited by diffusion or by interfacial reactions,
Numerical kinetic models also developed, for diffusion controlled reactions

Question 21

chemical potential of element

Answer 21

i is defined as the derivative of G (and also H ) with respect to the mole content of element i in the phase:

Question 22

ui is often referred to the

Answer 22

chemical potential

Question 23

Under equilibrium, the pressure and temperature

Answer 23

homogeneous in all points (phases) of the system (mechanical and thermal equilibrium)

Question 24

Young-Dupré relationships express

Answer 24

the static contact angle of a liquid drop on a solid substrate, in equilibrium with a gas phase