Term
| Corrosion is defined as the destructive and unintentional attack of a metal |
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Definition
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Term
| a single quantum of vibrational energy is called a phonon |
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Definition
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Term
| oxidation is to cathode as reduction is to anode |
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Definition
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Term
| metals with a more negative standard electrode are more cathodic |
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Definition
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Term
| galvanic corrosion is where two dissimilar metals are physically disjoined |
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Definition
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Term
| corrosion is the destructive electrochemical attack of a material |
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Definition
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Term
| metallic corrosion reactions are electrochemical, whereas polymeric degradation is physiochemical (involves both physical and chemical phenomena) |
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Definition
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Term
| polymer matrix composites consist of fibers as the matrix and a polymer resin as the reinforcement medium |
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Definition
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Term
| metals with a high passivity form a highly adherent, thin oxide film that increases with their exposure to corrosion |
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Definition
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Term
| a cold-worked metal is less susceptible to corrosion than the same material in an annealed state |
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Definition
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Term
| relatively strong interatomic bonding forces are found in many ceramic materials |
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Definition
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Term
| for polymers, increased crosslinking causes the magnitude of the expansion coefficient to decrease |
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Definition
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Term
| the transport of thermal energy from low to high temperature regions of a material is termed thermal conduction |
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Definition
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Term
| thermal shock is when brittle materials may experience fracture as a consequence of nonuniform dimensional changes |
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Definition
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Term
| a composite is a naturally occuring multiphase material |
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Definition
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Term
| the principle of combined action is always true for composites |
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Definition
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Term
| the thermal conductivity of plain carbon steel is greater than for a stainless steel because there are much higher concentrations of alloying elements in stainless steel |
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Definition
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Term
| a hybrid composite is a composite that is reinforced with two or more different fiber materials in a single matrix |
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Definition
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Term
| thermal shock resistance occurs due to uniform heating/cooling |
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Definition
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Term
| the property that characterizes the ability of a material to transfer heat is the thermal conductivity |
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Definition
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Term
| as relating to oxidation and reduction electrochemical reactions, the oxidation reaction occurs at the cathode and the reduction reaction occurs at the anode |
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Definition
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Term
| the site at which oxidation takes place is called the anode |
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Definition
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Term
| selective leaching is found in solid solution alloys and occurs when one element or constituent is preferentially removed as a consequence of corrosion processes |
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Definition
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Term
| small particle and dispersion strengthened composites are the two sub classifications of particle reinforced composites |
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Definition
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Term
| thermal conductivity is the property that characterizes the ability of a material to transfer heat |
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Definition
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Term
| aluminum is highly corrosion resistant in many environments because it passivates |
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Definition
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Term
| oxidation is sometimes called an anodic reaction |
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Definition
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Term
| electron energy bands have discrete energy states, yet the difference between two adjacent bands in exceedingly small |
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Definition
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Term
| the two types of polarization are activation and concentration |
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Definition
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Term
| maximum stress in the matrix occurs at the mid span of a crack in a composite |
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Definition
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Term
| corrosion occurs due to electrons that are given up by an oxidation reaction |
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Definition
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Term
| increasing T slows down an oxidation/reduction reaction |
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Definition
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Term
| a matrix is a continuous phase whose purpose is to transfer stress to other phases and protect phases from the environment |
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Definition
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Term
| particulate-reinforced properties can be isotropic or anisotopic |
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Definition
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Term
| thermal shock resistance is the ability of a material to be rapidly heated and not fracture |
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Definition
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Term
| thermal conduction is the phenomenon by which heat transfers from low to high temperature regions |
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Definition
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Term
| oxidation is the process by which an atom acquires an extra electron and becomes an anion |
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Definition
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Term
| reduction occurs at the cathode |
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Definition
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Term
| heat capacity is the ratio of energy change to the resulting temperature change |
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Definition
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Term
| metals have very good thermal conductivity because relatively large numbers of free electrons exist that participate in thermal conduction |
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Definition
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Term
| when the thermal expansion's potential energy vs. inter-atomic spacing curve for a solid material is symmetric, the inter-atomic spacing will change as the temperature change |
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Definition
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Term
| cold-worked metals are more susceptible to corrosion than non cold-worked metals |
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Definition
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Term
| hydrogen embrittlement only occurs to brittle materials |
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Definition
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Term
The Galvanic Series
a. Ranks the reactivity of metals/alloys in seawater
b. Shows which metals are more anode or cathode
c. Is the same as EMF
d. a and b
e. all of the above |
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Definition
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Term
Corrosion occurs due to:
a. the natural tendency of metals to give up electrons.
b. electrons are given up by an oxidation reaction.
c. these electrons then used in a reduction reaction.
d. all of the above
e. none of the above |
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Definition
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Term
Which of the following is NOT a type of metallic corrosion?
a. galvanic
b. intergranular
c. hydrogen embrittlement
d. selective leaching
e. stress corrosion |
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Definition
| c. hydrogen embrittlement |
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Term
Which of the following has a significant influence on the strength of fiber-reinforced
composites?
a. orientation of the fibers
b. fiber concentration
c. distribution of fibers
d. all the above
e. b and c |
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Definition
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Term
The mechanical characteristic of a fiber-reinforced composite depends on which of
following:
a. Properties of the fiber
b. Dispersion strengthening effect
c. Shear stress
d. Magnitude of the load transmitted to the fibers by matrix phase
e. a and d |
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Definition
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Term
The phenomenon by which normally active metals and alloys, under particular
environmental conditions, lose their chemical reactivity and become extremely inert is
known as:
a. Inhibition
b. Polymerization
c. Weathering
d. Passivity
e. A thermal transformation |
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Definition
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Term
The following is true about pitting:
a. It is a type of corrosive attack in which small pits or holes form.
b. It ordinarily occurs at the top of a horizontal surface in a downward, vertical
direction.
c. It is usually initiated by a localized surface defect, such as a scratch.
d. All of the above.
e. Both A and B. |
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Definition
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Term
Where do cracks associated with fatigue failure almost always initiate?
a. Below the surface of the material.
b. On the surface of the material.
c. On features such as scratches, fillets, keyways, threads, or dents.
d. Fatigue cracks initiate with no regard for features, shapes, or specific locations on a
material.
e. Both b and c. |
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Definition
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Term
What are the SI units for the coefficient of thermal expansion?
a. m/°C.
b. J·cm/°C.
c. N·s/m2.
d. °C-1.
e. Bα/mF. |
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Definition
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Term
Metals near the top of the galvanic series are
a. cathodic.
b. anodic.
c. unreactive.
d. reactive.
e. Both A and C. |
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Definition
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Term
Polymer deterioration by swelling may be reduced by
a. Increasing the degree of cross linking, increasing the molecular weight, and
increasing the degree of crystallinity.
b. Decreasing the degree of cross linking, decreasing the molecular weight, and
decreasing the degree of crystallinity.
c. Increasing the degree of cross linking, increasing the molecular weight, and
decreasing the degree of crystallinity.
d. Decreasing the degree of cross linking, increasing the molecular weight, and
increasing the degree of crystallinity.
e. None of the above. |
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Definition
a. Increasing the degree of cross linking, increasing the molecular weight, and
increasing the degree of crystallinity. |
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Term
What is the purpose of a matrix in a polymer-matrix composite?
a. To bind the fibers together.
b. To act as a medium by which stress is transmitted to the fibers.
c. To protect the fibers from damage.
d. To separate the fibers.
e. All of the above. |
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Definition
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Term
Heat capacity represents:
a. the amount of energy required to produce a unit temperature rise
b. the amount of energy necessary to change the space between molecules
c. the temperature a polymer can be raised to
d. all of the above
e. none of the above |
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Definition
| a. the amount of energy required to produce a unit temperature rise |
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Term
As a solid absorbs energy in the form of heat:
a. the temperature decreases
b. the temperature increases
c. the dimensions increase
d. both a and c
e. both b and c |
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Definition
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Term
The greater the atomic bonding energy, the deeper and more narrow the potential energy
trough. For which material(s) is this statement true?
a. ceramics
b. polymers
c. metals
d. a and b
e. all of the above |
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Definition
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Term
| Prime sources of thermal stresses are: a. erosion and compression b. shearing stresses and torque c. restrained thermal expansion and temperature gradients d. temperature gradients and fracture e. none of the above |
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Definition
| c. restrained thermal expansion and temperature gradients |
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Term
In high purity metals, the electron mechanism of heat transport is much more efficient
than the phonon contribution because:
a. metals are extremely good conductors of heat because of the free electrons that
participate in thermal conduction
b. electrons are not as easily scattered as phonons and have higher velocities
c. a hot region of a specimen represents a loss of kinetic energy
d. a and b
e. All of the above |
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Definition
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Term
Thermal conductivity:
a. is lower for a single crystal specimen compared to a polycrystalline one of the same
material.
b. is directly proportional to the electrical conductivity.
c. is normally higher for a pure metal compared to an alloy.
d. a and c
e. all of the above |
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Definition
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Term
What is concrete:
a. a common large-particle composite in which both matrix and dispersed phases are
ceramic materials.
b. are very thin single crystals that have extremely large length-to-diameter ratios.
c. considered to be a class of structural composites, are designed to be light-weight
beams or panels having relatively high stiffnesses and strengths.
d. A and C
e. None of the above |
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Definition
a. a common large-particle composite in which both matrix and dispersed phases are
ceramic materials. |
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Term
When does Galvanic corrosion occur:
a. exists when the reaction rate is limited by diffusion in the solution.
b. when two metals or alloys having different compositions are electrically coupled
while exposed to an electrolyte.
c. when metal atoms characteristically lose or give up electrons in what is called an
oxidation.
d. B and C
e. All of the above |
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Definition
b. when two metals or alloys having different compositions are electrically coupled
while exposed to an electrolyte. |
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Term
| Corrosion rate is influenced by: a. concentration of hydrogen ions b. fluid velocity c. current density d. a and b e. all of the above |
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Definition
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Term
All of the following are forms of corrosion except:
a. Galvanic
b. Crevice
c. Intergranular
d. Cathodic
e. Selective Leaching |
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Definition
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Term
Which of the following is/are sources of thermal stresses in a body:
a. restrained thermal expansion or contraction
b. bending of the body while it is heated or cooled
c. temperature gradients established during heating or cooling
d. a and c only
e. all of the above |
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Definition
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Term
A high degree of thermal shock resistance occurs when which of the follow properties are
present?
a. High fracture strength
High thermal conductivity
High modulus of elasticity
High coefficient of thermal expansion
b. High fracture strength
High thermal conductivity
Low modulus of elasticity
Low coefficient of thermal expansion
c. Low fracture strength
Low thermal conductivity
Low modulus of elasticity
Low coefficient of thermal expansion
d. Low fracture strength
Low thermal conductivity
High modulus of elasticity
High coefficient of thermal expansion
e. Thermal shock resistance does not depend on any of the above. |
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Definition
b. High fracture strength
High thermal conductivity
Low modulus of elasticity
Low coefficient of thermal expansion |
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Term
Which is NOT
a. Stress a form of corrosion?
b. Selective Leaching
c. Intergranular
d. Crevice
e. None of the above |
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Definition
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Term
This additive produces reduction in hardness and stiffness.
a. colorant
b. filler
c. stabilizer
d. plasticizer
e. fiber |
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Definition
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Term
Passivity corrosion consists of...
a. specific environmental conditions
b. inert due to formation of thin oxide film, may reform
c. stainless steel, aluminum
d. A &B
e. All of the above |
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Definition
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Term
What measure(s) can be taken to reduce the effects of galvanic corrosion?
1. If coupling of dissimilar metals is needed, choose two that are far
away from one another in the galvanic series.
2. Avoid an unfavorable anode-to-cathode surface area ratio; use the
largest possible anode area
3. Electrically insulate dissimilar metals from one another
a. 1
b. 2
c. 1&2
d. 2&3
e. 1,2,3 |
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Definition
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Term
Ceramic whiskers in composites may inhibit crack propagation by
a. Forming bridges across crack faces
b. Deflecting crack tips
c. Causing a redistribution of stresses in regions adjacent to the crack tips
d. Absorbing energy during pull-out as the whiskers debond from the matrix
e. All of the above |
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Definition
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Term
Which of the following are not forms of corrosion?
a. Uniform attack
b. erosion
c. Galvanic
d. stress
e. Pellucid |
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Definition
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Term
The measure(s) that may be taken to prevent, or at least reduce, corrosion include(s).
a. Material selection
b. Environmental alteration
c. Application of coating
d. Cathodic protection
e. All of the above |
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Definition
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Term
The displacement of each electrode potential from its equilibrium value is:
a. Corrosion penetration rate
b. Polarization
c. Passivity
d. Galvanic corrosion
e. None of the above. |
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Definition
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Term
This exists when the reaction rate is limited by diffusion in the solution.
a. Activation polarization
b. Concentration polarization
c. Corrosion
d. Pitting
e. None of the above. |
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Definition
| b. Concentration polarization |
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Term
This type of corrosion arises from the combined action of chemical attack and mechanical
abrasion or wear as a consequence of fluid motion.
a. Stress corrosion
b. Intergranular corrosion
c. Crevice corrosion
d. Erosion corrosion
e. None of the above |
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Definition
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|
Term
This type of corrosion is sometimes termed stress corrosion cracking, which results from
the combined action of an applied tensile stress and a corrosive environment.
a. Stress Corrosion
b. Intergranular corrosion
c. Crevice corrosion
d. Erosion corrosion |
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Definition
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Term
Thermal Stresses are stresses induced in a body as a result in a change of:
a. Polarity
b. Proton Charge
c. Temperature
d. Pressure
e. None of the above |
|
Definition
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Term
Which of the following is not a form of corrosion?
a. uniform attack
b. chipping
c. intergranular
d. erosion-corrosion
e. pitting |
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Definition
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Term
A copper wire 15m long is cooled from 40°C to -9°C. How much change in length will it
experience? The linear coefficient of thermal expansion for copper is 17.0 x 10-6(°C)-1
a. -12.55 mm
b. -10.43 mm
c. +5.3 m
d. None of the above |
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Definition
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Term
The heat flux through a brass sheet of 7.5 mm thick if the temperatures at the two faces
are 150°C and 50°C is:
Assume steady state heat flow and the thermal conductivity for brass is 120 W/m-K.
a. 1.6 x 103 W/m2
b. 3600 W/m2
c. 1.6 x 106 W/m2
d. 120 W/m-K
e. None of the above |
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Definition
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Term
If a bar of solid material fixed at both ends undergoes a drop in temperature, what is the
nature of the induced strain?
a. Tensile
b. Compression
c. There is no surface stress
d. a and b |
|
Definition
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Term
If a rod of brass 0.35m long is heated from 15°C to 85°C while its ends are maintained
rigid, determine the thermal stress that is develops. Assume the modulus of elasticity for
brass is 97GPa and he linear coefficient of thermal expansion is 20.0 x 10-6(°C)-1
a. + 136 MPa
b. - 136 MPa
c. + 58 MPa
d. - 58 MPa |
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Definition
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Term
For polymer materials:
a. The thermal conductivity depends on the degree of crystallinity
b. Amorphous materials shown a lower conductivity
c. Styrofoam makes a poor insulator
d. a & b
e. All of the above |
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Definition
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Term
| Thermal stress is created by: a. Restrained thermal expansion or contraction b. Surface flaws c. Thermal gradient d. a & c e. All of the above |
|
Definition
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|
Term
The thermal shock resistance depends on:
a. Temperature gradient
b. Mechanical properties of the material
c. Thermal properties of the material
d. Elastic modulus of the material
e. All of the above |
|
Definition
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Term
A thick steel sheet of area 100 in2 is exposed to air near the ocean. After a one year
period it was found to experience a weight loss of 485 g due to corrosion. To what rate
of corrosion does this correspond? K = 534, ρ = 7.9g/cm3
a. 37.4 mpy
b. 5.46 x 10-8 mpy
c. 895 mpy
d. None of the above |
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Definition
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|
Term
Which of the following(s) is(are) considered to be the most anodic?
a. Au3+ + 3e- → Au
b. K+ + e- → K
c. Pt2+ + 2e- → Pt
d. All of the above |
|
Definition
|
|
Term
Type(s) of corrosion:
a. Erosion corrosion
b. Intergranular corrosion
c. Galvanic
d. All of the above |
|
Definition
|
|
Term
Corrosion occurs in the following environments(s):
a. Salts
b. Atmosphere
c. Pure water
d. a & b
e. All of the above |
|
Definition
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|
Term
The corrosion rate can be reduced by:
a. Increasing the fluid velocity
b. Applying non-reactive coating to the material
c. Adding inhibitors
d. b & c
e. All of the above |
|
Definition
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|
Term
Which of the following material has very good corrosion resistance?
a. Stainless steel with 2% molybdenium
b. Polished steel
c. Aluminum alloy
d. a & b
e. All of the above |
|
Definition
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|
Term
Which of the following is the possible oxidation and reduction half reaction that occur
when magnesium is immersed is HCl solution?
a. Oxidation : Mg → Mg2+ + 2e- Reduction: 2H+ + 2e- → H2
b. Oxidation: H2 → 2H+ + 2e- Reduction: Mg2+ + 2e- → Mg
c. Oxidation: Mg → Mg2+ + 2e- Reduction: 4H+ + 4e- → H2O
d. None of the above |
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Definition
| a. Oxidation : Mg → Mg2+ + 2e- Reduction: 2H+ + 2e- → H2 |
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Term
Some metal M is placed in a solution containing hydrogen ions. Use the following
corrosion data and determine the rate of corrosion (r) of Metal M (in mol/cm2-s).
Assume activation polarization controls both oxidation and reduction reaction.
Metal M Hydrogen
V -0.9 V 0 V
i0 10-12 A/cm2 10-10 A/cm2
β +1.0 - 0.15
a. 6.31 x 10-8 mol/cm2-s
b. 3.27 x 10-13 mol/cm2-s
c. 5.28 x 10-10 mol/cm2-s
d. None of the above |
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Definition
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|
Term
Using the information from problem 117, compute the corrosion potential for this
reaction.
a. 0.1 V
b. -0.15 V
c. -0.42 V
d. None of the above |
|
Definition
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|
Term
Determine the Pilling-Bedworth (P-B) ratio for zinc:
Zn atomic mass = 65.39g/mo Oxygen atomic mass = 16g/mol
Zn density = 7.13 g/cm3 ZnO = 5.61 g/cm3
a. 1.58
b. 0.81
c. 3.25
d. None of the above |
|
Definition
|
|
Term
Does the ZnO coating in problem 119 protect the Zn metal from further oxidation?
a. No
b. Yes
c. No idea |
|
Definition
|
|
Term
For Pilling – Bedworth (P-B) ratio is less than 1, the oxide film is:
a. Porous
b. Flaky
c. Protective
d. Well bonded |
|
Definition
|
|
Term
For stress corrosion to occur, the following is (are) required:
a. Corrosive environment
b. Tensile stress
c. Compressive stress
d. a & b
e. All of the above |
|
Definition
|
|
Term
| The polarization curve for a metal that passivates will show a constant current density as the electrochemical potential: a. Increases b. Decreases c. Constant d. None of the above |
|
Definition
|
|
Term
Crack spacing in a fiber reinforced composite material:
a. decreases as bond stress increases
b. increases as fiber diameter increases
c. decreases as the fiber content increases
d. increases as the matrix strength increases
e. all of the above |
|
Definition
|
|
Term
After cracking, the active component in FRC is
a. the matrix
b. the fiber
c. a combination
d. depends on the efficiency level
e. all of the above |
|
Definition
|
|
Term
At a crack in FRC:
a. stress in the matrix is minimal
b. stress in the fiber is maximum
c. bond slip occurs
d. a and b
e. all of the above |
|
Definition
d. a and b
OR
e. all of the above |
|
|
Term
Bond stress:
a. transfers stress from the fiber to the matrix
b. affects the critical length
c. affects the matrix cracking interval
d. is greater in the center of the cracking interval
e. all the above |
|
Definition
|
|
Term
A particulate composite consists of two materials (A and B) that have the following
proportions and properties:
Percentage Volume of Material A = 30%,
Modulus of Elasticity of Material A = 30,000 psi
Percentage Volume of Material B = 70%,
Modulus of Elasticity of Materials B = 60,000 psi
The modulus of elasticity of the composite according to the series model is:
a. 60,000 psi
b. 51,000 psi
c. 48,577 psi
d. 46,154 psi
e. none the above |
|
Definition
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|
