Week 2: Ceramics

Question 1

compound of metallic and non-metallic elements

Answer 1

ceramics

Question 2

ceramics are _____ (3) than metals

Answer 2

• more biocompatible
• safer
• have better esthetics

Question 3

properties of ceramics

Answer 3

• very strong/stiff
• brittle
• dense
• refractory
• do not corrode

Question 4

retaining strength at high temperatures

Answer 4

refractory

Question 5

ceramics form ______ between atoms

Answer 5

ionic bonds

Question 6

which is stronger, metallic bond or ionic bond?

Answer 6

ionic bond

Question 7

ceramics are ____

Answer 7

brittle

Question 8

mechanism for fracture of ceramics

Answer 8

-easy propagation of cracks when under tension stresses

Question 9

ceramics are not brittle when they are under _____ ___ because the cracks do not _____

Answer 9

compression stresses, propagate

Question 10

key to mechanical reinforcement of ceramics:

Answer 10

difficult/hinder propagation of cracks

Question 11

two methods of hindering propagation

Answer 11

• incorporating a component (ex: alumina)

- transformation toughening

Question 12

summary of transformation toughening

Answer 12

• yttria/yttrium oxide in structure
• tetragonal structure –> monoclinic structure
• ^occurs at tip of crack, increases compression stress (ceramics less brittle with this type)

Question 13

transformation toughening is exclusively for use of…

Answer 13

zirconia-based ceramics

Question 14

are inert ceramics used in dentistry?

Answer 14

yes, most commonly used