Diffusion
What is Ficks 1st law?
J=−D(∂C/∂X)
Coined by Clausius in the 1850s, this thermodynamic quantity is often the driving force for material defect formation.
Entropy
Where did Scharf go to graduate school?
University of Alabama
This type of polymer structure is characterized by a branching network of molecules, which gives it its unique properties, such as being highly resistant to chemical breakdown.
crosslinked polymer
What is the primary characteristic that distinguishes ceramics from metals and polymers?
Ceramics are primarily characterized by their strong ionic and covalent bond
What is Ficks 2nd law (or the relative relation) x = root(Dt)?
∂C/∂t=D(∂2C/∂x2)
A pioneer in statistical mechanics, engraved on this Austrian physicist’s tombstone is an equation bearing his constant.
Boltzmann
Periodic table trends: atomic radius ______ going down groups and ________ from left to right.
Increases, decreases
This polymer is the most commonly used synthetic fiber and is also known for being a key component in materials like plastic bottles and food containers.
polyethylene terephthalate (PET)
In ceramics, what is the term used to describe the process of heating raw ceramic materials to a high temperature to remove moisture and harden the material?
The process is called firing.
What is Fick's 3rd Law?
There is none!
In the Haber-Bosch process, atmospheric nitrogen reacts with hydrogen to form ammonia in the following reaction:
N2+3H2=2NH3 , ∆Hrxn= −92.28kJ
Which direction does the reaction proceed with an increase in temperature?
To the left/backwards.
A model describing the bond energy curves for two interacting particles.
Lennard-Jones potential
The degree of polymerization (DP) is defined as the ratio of the molar mass of the polymer to the molar mass of the repeating unit. This term is often used to describe the length of the polymer chains, but it can be directly related to the molecular weight distribution of the polymer.
What is the number-average molecular weight MnM_nMn?
Which type of ceramic structure is typically associated with materials like alumina (Al₂O₃) and zirconia (ZrO₂), and how does it affect their properties?
Alumina and zirconia typically have a corundum-type
What are the 3 main types of diffusion in a metallic structure
Vacancy, interdiffusion, interstitial
Suppose you have the following endothermic, gas-phase reaction:
A=2B+CA=2B+C
Qualitatively describe the temperature(s) at which the reaction would occur spontaneously in the forward(right) direction.
High temperatures
Ordered form of FCC and BCC structures?
L12 and B2
This technique is used to measure the thermal transitions of a polymer, such as its glass transition temperature (Tg) and melting temperature (Tm), by monitoring changes in heat capacity.
differential scanning calorimetry (DSC)
What is the phenomenon called when a ceramic material, such as zirconia, undergoes a phase transition that helps to arrest cracks and increase fracture toughness?
This phenomenon is called transformation toughening
A gear made of 1020 steel (0.2 wt% C) is to be gas-carburized at 927°C (1700°F). Calculate the carbon content at 0.040 in. below the surface of the gear after a 7.0 hour carburizing time. Assume the carbon content at the surface of the gear is 1.15 wt %. Assume D for C in Fe at 927°C = 1.28 × 10-11 m2/s.
0.394 wt % C
The distribution of molecular energies for a gas in thermal equilibrium at absolute temperature T is given by the Maxwell-Boltzmann distribution:
*insert equation*
E = 1/2kT
What are the 7 crystal systems?
Cubic, Hexagonal, Tetragonal, Rhombohedral (Trigonal), Orthorhombic, Monoclinic, Triclinic
Compute the repeat unit molecular weight for poly vinyl chloride
m = 2(AC) + 3(AH) + (ACl)
= (2)(12.01 g/mol) + (3)(1.008 g/mol) + 35.45 g/mol = 62.49 g/mol
What defect type is responsible for ionic conductivity in oxide ceramics like ceria (CeO₂), and what is the associated defect equation?
Oxygen vacancy – Schottky
Defect equation:
CeO2 = 2VO+++VCe’’’’