Electroless Deposition Quizes
AESF Foundation Training Course:
Electroless Deposition-Lesson 1 Chemistry
Review Quiz:
1. If an acidic solution has a pH of 3.0, what is the normality of the acid?
2. A 2 molar solution of H2SO4 contains _______ g/L, while a 2N solution of H2SO4 contains________ g/L.
/
3. True [ ] or False [ ]: In water-based solutions, pH is defined by the equation pH = log [H+]
4. If ionic aluminum has a valence of +3 and the valence of oxygen is -2, the correct formula for aluminum oxide is:
____a. AlO3
____b. AlO2
____c. Al2O3
____d. Al3O2
5. True [ ] or False [ ]: The element, boron, is one of several elements that fall into the “metals” category.
6. A five mL solution of NaOH is neutralized by ten mL of 1N H2SO4.
The normality of the NaOH solution is __________ .
7. Complete the equation NaOH + H2SO4 ® Na2SO4 + H2O
8. Surface tension is produced because water molecules are ______________ .
9. 1 oz/gal = ___________mg/L = _________________ ppm (solution SPG = 1.0)
10. Which of the following are the strongest bonds?
______ a. covalent
______ b. ionic
______ c. chelated
______ d. none of the above
11. An acid is a substance that produces an excess of ______ ions when added to water.
12. A reaction tends to go to completion when:
____a. The product is ionized
____b. The product is a gas and can leave the vessel
____c. The product is insoluble
____d. All of the above
13. The main purpose of a complexing agent in electroless nickel solutions is to
____a. control the temperature of the solution
____b. prevent the formation of insoluble nickel compounds
____c. speed up the rate of deposition
____d. prevent gas pitting
____e. All of the above
14. The best choice for acid pickling of leaded brass is
____a. sulfuric
____b. fluoboric
____c. nitric
____d. nitric plus sulfuric
____e. None of the above
15. Assuming the following valences:
O = -2
H = +1
SO4 = -2
CrO4 = -2
In the reaction: 3H2SO3 + 2H2CrO4 ® Cr2(SO4)3 + 5H2O, which atom is reduced and which is oxidized?
____a. Hydrogen is oxidized and oxygen is reduced
____b. chromium is reduced and hydrogen is oxidized
____c. chromium is oxidized and oxygen is reduced
____d. chromium is reduced and sulfur is oxidized
____e. sulfur is reduced and is chromium oxidized
AESF Foundation Training Course:
Electroless Deposition,
Lesson 02: Overview, Review Quiz:
1. The reducing agent for producing an EN-P deposit is __________________ _____________________________________.
2. High phos EN-P typically contains more than ______%P.
3. High phos EN is typically used for its
______a. Solderability
______b. Weldability
______c. Appearance
______d. Ductility
______e. all of the above
______f. none of the above
4. Medium phos EN is typically employed for
______a. best corrosion resistance
______b. best solderability
______c. best combination of corrosion resistance, wear and economy
______d. best heat treatability
______e. all of the above
______f. none of the above
5. Low Phos Ni is typically employed for
______a. best corrosion resistance
______b. best solderability
______c. best heat treatability
______d. all of the above
______e. b and c
6. Alkaline EN processes may be employed for
______a. best corrosion resistance
______b. plating on plastics
______c. best heat treatability
______d. plating over zincated aluminum
______e. b and c
______f. b and d
7. The most basic (two) ingredients of an EN-P solution are
______a. Nickel sulfate or nickel chloride plus lead acetate
______b. Nickel sulfate or nickel chloride plus boric acid
______c. Nickel sulfate or nickel chloride plus sodium hypophosphite
______d. Nickel sulfate or nickel chloride plus thiourea
______e. none of the above
8. Which of the following metal surfaces is not catalytic in a common EN solution reduced with hypophosphite?
______a. Steel
______b. Zincated aluminum
______c. Nickel
______d. Copper
______e. none of the above
9. True [ ] or False [ ]: Traces of lead or thiourea have historically been used as stabilizers in a common EN-P solution.
10. When EN-P or EN-B is heat treated at the proper temperature and for the correct amount of time, which of the following changes occur to the deposit:
______a. Deposit is softer than as plated and amorphous in structure
______b. Deposit is harder than as plated and better in corrosion resistance
______c. Deposit contains an intermetallic between nickel and phosphorus (or boron)
______d. Deposit is lower in corrosion resistance than as plated
______e. a and b
______f. c and d
11. True [ ] or False [ ]: Common reducing agents for producing Ni-B include sodium borohydride and dimethyl sulfonic acid (DMSA).
12. [ ] True [ ] False: Sodium borohydride can be used to deposit Ni-B from an EN solution at pH 5.
13. Surfactants that may be employed in electroless nickel plating solutions are either cationic or
______a. sulfurized
______b. anionic
______c. catatonic
______d. non-ionic
______e. none of the above
14. Composite EN-P-PTFE coatings typically contain between ____ and _____% by volume of PTFE particulates.
15. [ ] True [ ] False: Immersion plating and electroless plating are the same process.
16. Excessive concentration of stabilizer can cause
______a. low plating speed
______b. low corrosion resistance
______c. edge effects
______d. skip plating
______e. all of the above
17. [ ] True [ ] False: Some buffers that may be part of an EN formulation can also act as complexing agents
18. Using nickel hypophosphite instead of sodium hypophosphite has the following advantage:
______a. higher plating speed
______b. higher corrosion resistance
______c. introduces no undesirable ions
______d. no skip plating
______e. none of the above
19. If an aluminum or zincated part is to be EN-B plated, the borohydride solution might:
______a. be the best choice
______b. chemically attack the parts
______c. plate slower than the DMAB solution
______d. produce a soft deposit
______e. none of the above
20. A deposit produced from an amine-borane EN-B solution may be excessively stressed if the thickness is greater than about ______ microns.
AESF Foundation Training Course:
Electroless Deposition,
Lesson 03, Properties of EN
Review Quiz
1. [ ] True or [ ] False: The density of an EN-P or an EN-B deposit is increased as the alloy increases in phosphorus/boron content.
2. [ ] True or [ ] False: While the phosphorus in EN-P deposits is typically uniformly dispersed, the boron in EN-B deposits tends to be non-uniform.
3. [ ] True or [ ] False: The cauliflower-like surface of EN-P deposits partially explains the high level of wear resistance, since the gaps between the bumps can retain lubricants.
4. In comparing the salt spray performance of EN-P with EN-B, 10-25 microns of a 5th generation EN-B deposit tends to:
____a. perform better than high-phos EN-P
____b. perform as well as high-phos EN-P
____c. perform better than low and mid-phos EN-P
____d. perform worse than any EN-P deposit
____e. none of the above
5. [ ] True or [ ] False: While heat treating EN-P deposits typically reduces corrosion resistance, at temperatures greater than 600ºC, a dense intermetallic may form at the substrate-plating interface and actually enhance corrosion resistance.
6. [ ] True or [ ] False: EN-B deposits tend to resist corrosion better in neutral or acidic environments vs. those that are alkaline.
7. [ ] True or [ ] False: A part that has a rough surface may require 50-100% more plating vs. one that has a smooth surface.
8. The impact on the fatigue strength of an EN-P plated part is dependent upon:
____a. %P
____b. plating thickness
____c. thermal treatments, if any
____d. a and b but not c
____e. a, b and c
____f. none of the above
9. [ ] True or [ ] False: Because EN-B deposits are generally compressively stressed, they do not impact the fatigue strength of an EN-B plated part.
10. [ ] True or [ ] False: In general, EN-P deposits display a harder “as plated” condition vs. EN-B deposits.
11. [ ] True or [ ] False: The as plated hardness of EN-P goes down if the %P goes up.
12. [ ] True or [ ] False: The as plated hardness of EN-B goes down if the %B goes up.
13. [ ] True or [ ] False: Based on data from the Nickel Development Institute, the heat treatment temperature for obtaining the maximum hardness of an EN-P deposit should be adjusted based upon the %P.
14. [ ] True or [ ] False: Based on data from the Nickel Development Institute, the heat treatment of an EN-4%B deposit should be conducted in less than 20 minutes, if the temperature is 400-500ºC.
15. [ ]True or [ ] False: Adhesion of EN deposits over aluminum can be enhanced by baking 1-4 hours at 400-550°C.
16. Which is more ductile?
____a. EN-10%P
____b. EN-5%B
____c. they are equally ductile
17. Which of the following composite EN deposits can match the Taber Wear Index of hard chromium?
____a. EN-P + Silicon carbide
____b. EN_P + aluminum oxide
____c. EN-P + boron carbide
____d. EN-P + diamond
____e. all of the above
____f. none of the above
18. [ ]True or [ ] False: the internal stress of an EN-P deposit can be compressive, if it is very low or very high in %P
19. [ ]True or [ ] False: In general, EN-B deposits are typically lower in internal stress vs. EN-P deposits.
20. [ ]True or [ ] False: EN-P and EN-B deposits typically lose all of their magnetic properties when the %P and the %B exceed 6.4% in concentration.
AESF Foundation Training Course:
Electroless Deposition,
Lesson 04: Equipment for Electroless Plating, Review Quiz:
1. The minimum total surface area to volume of electroless plating solutions is______________________________________________________________
2. What are the common plating tank materials of construction:
___________________________________________
____________________________________________
____________________________________________
3. What is the pore size for filtration of an EN process solution?
_____________________________________
4. What are the methods of heating EN solutions?
___________________________________________
____________________________________________
____________________________________________
5. At what size are exterior supports needed for polypropylene tanks?_______ gallons.
6. What are some simple energy conservation devices for EN tanks? ___________________________________________
____________________________________________
____________________________________________
7. Which of the following materials should NOT be used for long term service piping on an EN process tank?
____ (a) CPVC
____ (b) Polypropylene
____ (c) glass
____ (d) Kynar®
____ (e) Stainless steel
____ (f) polycarbonate
8. The purpose of agitation of an EN solution is to
___________________________________________
____________________________________________
9. Is carbon filtration of an EN plating solution a good idea? When?
___________________________________________
___________________________________________
10. What are the benefits of automated analysis and control of an EN process?
__________________________________________________________________________________________________________________________________________________________
___________________________________________
AESF Foundation Training Course:
Electroless Deposition,
Lesson 05: Pre & Post Plate Processing Part-1,
Review Quiz:
1. The basic preparation “secret” for aluminum is___________________________.
2. What is the activation process for stainless steels or nickel alloys?
3. Best first plated layer over zincate is_________________.
4. When cleaning a part, the best location for ultrasonics is:
____a. the EN solution
____b. the soak cleaner
____c. the acid pickle
____d. none of the above
5. [ ] True [ ] False: The zincate formulation that is used for magnesium is the same basic formulation as for aluminum.
6. Name three of the control parameters of a zincate for aluminum? ___________________________________________
____________________________________________
____________________________________________
7. [ ] True [ ] False: Magnesium can be plated without a zincate.
8. [ ] True [ ] False: When plating magnesium without a zincate the EN plating solution needs to be modified in chemistry
9. [ ] True [ ] False: The EN plating solution formulation for plating magnesium without a zincate contains fluoride(s).
10. [ ] True [ ] False: Periodic reverse cleaning does not expose high strength steel to hydrogen.
AESF Foundation Training Course:
Electroless Deposition,
Lesson 06: Pre & Post Plate Processing Part-2,
Review Quiz:
1. [ ] True [ ] False: Beryllium is treated using a zincate as part of the preparation cycle.
2. [ ] True [ ] False: Zinc die castings typically have buffing compound on the surface
3. Which of these acids would you chose for pickling zinc die castings:
_____ 2% vol sulfuric
_____ 2 %vol nitric
_____ 2%vol Hydrochloric
4. A major problem with powder metallurgy is
_____ a. Surface Passivity
_____ b. Surface porosity
_____ c. Surface oxides
_____ d. None of the above
5. The acid in most any EN stripping solution is most likely _____________.
6. Which of the following acids would you use to strip EN off aluminum?
_____ 50% vol sulfuric
_____ 50%vol nitric
_____ 50%vol Hydrochloric
7. Activation process for tungsten may employ an etch in hot ________________________.
8. As taught in this lesson, molybdenum may be electrolytically etched using
_____ a. a chromic acid solution
_____ b. KOH
_____ c. nitric-phosphoric
_____ d. none of the above
9. Pure Mo can be activated using a cathodic activation treatment in___________________ acid followed by a sulfamate nickel strike.
10. If a steel part needs repetitive stripping of EN, the acidic solution most likely to be used probably will contain ___________________ acid.
11. [ ] True or [ ] False: Some high strength steel and heat treated Be-Cu alloys require stress relief baking before stripping defective EN deposits.
12. Powder metallurgy parts that exhibit surface porosity may be treated with
_____ a. chromic acid
_____ b. KOH
_____ c. vacuum impregnation
_____ d. none of the above
13. According to BAC 5771, hydrogen sensitive parts should be relief baked within _____ hrs. of stripping.
14. [ ] True or [ ] False: Adhesion of EN deposits on titanium substrates is improved by thermal treatment at 390ºC.
AESF Foundation Training Course:
Electroless Deposition,
Lesson 07: Hypophosphite Reduced Solutions
Review Quiz:
1. What is the most commonly employed reducing agent for EN-P?
____ a. Nickel chloride
____ b. Nickel sulfate
____ c. Nickel acetate
____ d. Nickel orthophosphite
____ e. None of the above
2. What is the main advantage to using nickel hypophosphite as the reducing agent?
____ a. Lower cost
____ b. lower carbon footprint
____ c. no need for a complexing agent
____ d. contains no undesirable anion
____ e. None of the above
3. If the Ni content drops below about 4g/L in an EN-P solution, the most likely effect on the process is:
____ a. increased plating speed
____ b. increase in the %Ni in the deposit
____ c. decrease in %Ni in the deposit
____ d. increase in the brightness of the deposit
____ e. None of the above
4. A complexing agent that has a high stability constant has what effect in an EN-P process:
____ a. increases the %Ni in the deposit
____ b. decreases the %Ni in the deposit
____ c. decreases the stability of the solution
____ d. increase in the brightness of the deposit
____ e. None of the above
5. Operating an EN-P solution at the high end of the pH range:
____ a. increases the %Ni in the deposit
____ b. decreases the %Ni in the deposit
____ c. decreases the plating speed
____ d. increases the plating seed
____ e. a and c
____ f. a and d
____g. None of the above
6. [ ] True [ ] False: Some EN-P complexing agents also act to buffer the pH
7. Which of the following is a stabilizer?
____a. Lead acetate,
____b. lead sulfide,
____c. thiosulfate,
____d. thiourea,
____e. molybdic acid
____f. thiocyanate
____g. All of the above
8. Even if an EN-P solution contains a stabilizer, the plated parts may develop edge pull-back if:
____a. the stabilizer is lead acetate,
____b. the pH of the EN solution is too high
____c. the agitation level is too low
____d. the agitation level is too high
____e. the solution is air agitated
____f. the solution has no agitation
____g. none of the above
9. An a typical EN-P solution, incorporation of a surfactant into the solution formulation has which of these effects:
____a. reduces pitting tendency
____b. increases plating speed
____c. produces a much harder as-plated deposit
____d. produces a much softer as-plated deposit
____e. none of the above
____f. a and b
____g. a and c
10. [ ] True [ ] False: Brightener for typical EN-P solutions fall into two categories; organic or inorganic.
11. [ ] True [ ] False: Typical EN-P solutions can tolerate a higher concentration of orthophosphite at the higher end of the operating pH range.
12. [ ] True [ ] False: As a typical EN-P solution is used, the specific gravity of the solution is decreased by the accumulation of reaction by-products.
13. [ ] True [ ] False: Nitrates can be especially beneficial in a typical EN-P solution, by accelerating the plating speed.
14. Lactic acid, acetic acid, glycolic acid and propionic acid are common _______________ ______________ that may be part of an EN-P solution formulation.
15. What is the major contaminant that builds up over time in a common EN-P solution and eventually causes the plater to replace the plating solution?
____ a. Orthophosphate
____ b. Pyrophosphate
____ c. Megaphosphite
____ d. Orthophosphite
____ e. None of the above
16. [ ] True [ ] False: When comparing a citrate complexed to a pyrophosphate complexed alkaline EN-P solution, the citrate complexed solution has a higher plating speed at all operating temperatures.
17. While hypophosphite is a more powerful reducing agent in alkaline EN-P solutions, one major drawback to such a process is:
____ a. inability to plate zincated aluminum
____ b. inability to plate at temperatures lower than 90ºC
____ c. inability to plate alloys containing >7%P
____ d. None of the above
18. [ ] True [ ] False: While “non-proprietary” alkaline EN-P solution complexed with citrate plate at a constant speed, even if the pH changes from 8 to 11, pyrophosphate complexed solutions will plate at varying speed based not only on pH, but also on plating time.
AESF Foundation Training Course:
Electroless Deposition,
Lesson 08: EN-B Solutions, Review Quiz:
1. In electroless plating, which of the following describes the anodic reaction:
____ a. Electrons produced at the anode convert atomic nickel to ions
____ b. A reducing agent is chemically reduced to produce electrons
____ c. A reducing agent is chemically oxidized to produce electrons
____ d. Electrons produced at the catalytic surface reduce metal ions to atomic metal
____ e. None of the above
2. Which of the following is a draw-back to amine-borane solutions?
____ a. Relatively slow plating speed
____ b. thick deposits have high tensile stress
____ c. limited plating thickness
____ d. not suitable for wear applications
____ e. All of the above
3. [ ] True [ ] False: Amine-borane reduced EN-B tend to be favored over borohydride reduced solutions because they are more stable and can be operated for significantly more MTOs
4. [ ] True [ ] False: The %B in deposits from amine-borane reduced EN-B solutions is limited 2% or less.
5. [ ] True [ ] False: Air agitation is favored in EN-B plating processes.
6. [ ] True [ ] False: Nickel chloride is favored for producing high purity EN-B deposits
7. Above about _______g/L nickel, the %B in the deposit tends to be relatively constant.
____a. 50 to 60
____b. .5 to 1.0
____c. 12 to 24
____d. 5 to 6
____e. none of the above
8. [ ] True [ ] False: Up to about 2.5 to 3g/L of DMAB, and increase in DMAB causes an increase in %B in the deposit.
9. [ ] True [ ] False: Initially, an increase in complexer concentration increases the %B in the deposit. However, at some point, and increase actually decreases the %B
10. Which of the following are stabilizers in EN-B solutions:
____a. lead compounds
____b. organic compounds containing sulfur
____c. ethylene diamine
____d. a and c
____e. a and b
____f. none of the above
11. DMAB decomposes rapidly above which of these temperatures (in degrees C)
____a. 25
____b. 45
____c. 55
____d. 65
____e. 70
____f. none of the above
12. [ ] True [ ] False: For DMAB solutions, lower pH produces higher plating speed but lower %B
13. If the pH of a DMAB solution is too high, which of the following is a distinct possibility:
____a. deposits will be brighter than normal
____b. deposits will be rough
____c. deposits will be stressed
____d. the solution may decompose
____e. all of the above except a
____f. none of the above
14. DMAB decomposes rapidly if the solution pH is lower than about ____________.
15. What is a major drawback of a borohydride reduced EN-B solution?
____ a. deposits are hard and wear resistant
____ b. the high pH is incompatible with aluminum and other pH sensitive metals
____ c. the cost of operation is much higher than DMAB solutions
____ d. all of the above except a
____ e. None of the above
16. If the pH of a borohydride solution drifts below about ____, the borohydride rapidly decomposes
17. About ________% of the sodium borohydride in a borohydride solution is consumed in about _______ minutes of plating.
18. [ ] True [ ] False: The solution temperature of a borohydride reduced solution can range from 90 to 97ºC, without a significant impact on the process.
19. For borohydride reduced solutions, operating at a lower temperature ____________ (increases or decreases) the %B in the deposit.
20. [ ] True [ ] False: For borohydride reduced solutions stabilized with lead tungstate, the lead in the deposit typically exceeds 0.15% which exceeds RoHS limits.
AESF Foundation Training Course:
Electroless Deposition,
Lesson 09: Troubleshooting EN, Review Quiz:
1. When considering the parts in conducting troubleshooting, it can be assumed that deposit thicknesses under ______ microns tend to produce rejects.
2. A poor corrosion resistance issue may be the result of:
_______(a) poor deposit quality
_______(b) a smooth substrate
_______(c) poor chemistry conditions
_______(d) 10-11 %P in the deposit
_______(e) all of the above
_______(f) a and c
_______(g) none of the above
3. The most likely place to find a cause of poor adhesion is:
_______(a) the solution pH
_______(b) the solution temperature
_______(c) %P in the deposit
_______(d) the pretreatment method(s)
_______(e) all of the above
_______(f) a and c
_______(g) none of the above
4. Calcium and silicates may react to produce:
_______(a) a change in the solution pH
_______(b) a hard to remove film
_______(c) low thickness
_______(d) poor adhesion
_______(e) all of the above
_______(f) b and d
_______(g) none of the above
5. A good operating practice is to avoid plating aluminum substrates in EN solutions that are:
_______(a) at a pH of 8
_______(b) new
_______(c) over 4 MTOs
_______(d) air agitated
_______(e) none of the above
6. The most likely cause of a rough EN deposit is:
_______(a) High solution pH
_______(b) High temperature
_______(c) tank plate-out
_______(d) formation of nickel phosphite
_______(e) all of the above
_______(f) b and d
_______(g) none of the above
7. Copper and nitrate contamination of an EN solution containing one or more sulfur-type stabilizer can cause the production of a pitted deposit because they:
_______(a) a change in the solution pH
_______(b) produce a hard to remove film
_______(c) lower the stabilizer concentration
_______(d) react with each other
_______(e) all of the above
_______(f) b and d
_______(g) none of the above
8. An EN solution that produces a deposit that is normally bright, but now produces a dull deposit may have the following condition(s):
_______(a) low hypophosphite content
_______(b) low MTOs
_______(c) low nickel content
_______(d) low pH
_______(e) low temperature
_______(f) all of the above
_______(g) all of the above except “b”
9. An EN deposit that is brittle/high stressed may be produced from a solution that has:
_______(a) PO3 greater than 80g/L
_______(b) too many MTOs
_______(c) 6g/L nickel content
_______(d) a pH of 5-6
_______(e) Si content greater than 6ppm
_______(f) all of the above
_______(g) all of the above except “c” and “d”
10. [ ] True or [ ] False: Patterns/streaks can be caused by poor agitation, low tank loads, an over-stabilized bath, or nitric acid contamination.
11. [ ] True or [ ] False: If an EN solution produces a deposit that is more “active” than normal, it may be more likely dark and or streaked.
12. Edge pull-back is most likely caused by:
_______(a) low temperature
_______(b) low pH
_______(c) excessive agitation
_______(d) high stabilizer content
_______(e) low work-load
_______(f) all of the above
_______(g) all of the above except “c”
13. An EN deposit failed a salt spray test. Possible causes to consider are:
_______(a) Excessively rough substrate
_______(b) too many MTOs
_______(c) %P is higher than 10
_______(d) high solution temperature
_______(e) high pH
_______(f) all of the above
_______(g) all of the above except “c”
14. Slow plating speed can be caused by:
_______(a) low temperature
_______(b) low nickel content
_______(c) low hypophosphite content
_______(d) a pH of 5-6
_______(e) high MTOs
_______(f) all of the above
_______(g) all of the above except “d”
15. [ ] True or [ ] False: Corrective actions for solution white-out include cooling the solution and raising the pH until the solution turns clear.
16. A heat exchanger that is excessively hot, but has no hot spots can cause ________________ ________________ on the tank and equipment.
17. A heat exchanger that has hot spots can cause the solution to ________________________.
18. EN solutions containing ammonia may produce rapid changes in ____________ if they are operated at excessively high temperature or air agitation.
19. EN solutions may produce no deposit under the following conditions:
_______(a) high temperature
_______(b) high nickel content
_______(c) high hypophosphite content
_______(d) workload of 0.5-0.75ft2/gal
_______(e) all of the above
_______(f) none of the above
_______(g) all of the above except “d”
20. When conducting a performance test on an EN solution, the thickness plated in the test should be:
_______(a) higher than the thickness on the actual parts
_______(b) the same as the thickness on the actual parts
_______(c) <5 microns
_______(d) >5microns but <10 microns
_______(e) none of the above
AESF Foundation Training Course:
Electroless Deposition,
Lesson 10: Quality Control Testing, Review Quiz:
1. When developing a quality control system, three areas that require control by operators include process analysis/history, qualification tests and
____a. Measuring the tank dimensions
____b. Acceptance tests
____c. pH measurement
____d. none of the above
2. It is important to maintain all operating parameters within a ___________ (narrow or broad) range to assure consistent quality
3. ICP and AA instruments can be used to detect the following in EN solutions:
____a. carbonates
____b. alkalinity
____c. trace metals
____d. cyanide
4. The Ferroxyl test is used to detect porosity in EN over which type of substrate(s):
____a. aluminum
____b. magnesium
____c. titanium
____d. none of the above
5. The presence of porosity in an EN deposit, using the Ferroxyl test, is indicated by the presence of:
____a. red blotches
____b. black spots
____c. blue spots/lines
____d. none of the above
6. Name three adhesion tests for EN coatings:
_______________________________________ ________________________________________ _______________________________________
7. [ ] True or [ ] False: The rising step load test for hydrogen embrittlement provides only a pass-fail answer.
8. The hot chloride test is used to detect what imperfection in EN deposits?
____a. presence metallic impurities
____b. blisters
____c. soft deposits
____d. porosity
____e. None of the above
9. The % P of an EN coating can be determined volumetrically and _________________________.
10. XRF is a test for EN___________________________________________________.
11. [ ] True or [ ] False: Coulometric thickness testing devices are non-destructive.
12. A profilometer can be used to measure:
____a. pH
____b. surface roughness
____c. surface hardness
____d. reflectivity
____e. None of the above
13. Which of the illustrations below illustrates a tensile stressed EN deposit:
A B C
____a. Illustration A
____b. Illustration B
____c. Illustration C
____d. Illustration A and C
____e. None of the above
14. If a solderability test results in “dewetting”, this means
____a. the surface is highly solderable
____b. the surface is wet
____c. the surface is not highly solderable
____d. the surface is hydrophobic
____e. None of the above
15. [ ] True or [ ] False: A Knoop indentor may be favored over a Vickers indentor in cases where the indentor cannot travel too deep into the deposit.
AESF Foundation Training Course:
Electroless Deposition
Lesson 11: Stripping EN Deposits, Review Quiz
1. [ ] True or [ ] False: The basic reaction conducted when chemical stripping parts is chemical reduction which leaves the parts in a passive state.
2. [ ] True or [ ] False: Before stripping a part, it is important for the operator to know as much about the coating and substrate as possible.
3. [ ] True or [ ] False: Whenever possible, stripping in an electrolytic stripping process is preferred over immersion stripping.
4. [ ] True or [ ] False: Electrochemical strippers are more prone to produce pitting than immersion strippers.
5. [ ] True or [ ] False: Aside from immersion and electrolytic stripping, mechanical means can also be used as long as the part and specification allows it.
6. [ ] True or [ ] False: Steel part below Rockwell 35c do not need to be stress relieved before or hydrogen embrittlement baked after stripping.
7. [ ] True or [ ] False: Coil springs should always be stress relieved before stripping to avoid hydrogen effects.
8. [ ] True or [ ] False: According to Boeing, the shortest bake time after stripping and before re-plating is 3 hours.
9. [ ] True or [ ] False: When preparing an acidic stripping solution the acid is the last liquid added when multiple liquids need to be mixed up.
10. [ ] True or [ ] False: The stripping solution should be controlled to within +/-5ºC of the optimum operating temperature.
11. [ ] True or [ ] False: It is good practice to check aluminum parts every 5 minutes during the stripping operation.
12. [ ] True or [ ] False: If parts are partially immersed during stripping, the air-surface interface will most likely be severely attacked.
13. [ ] True or [ ] False: The appearance of a new (and different) metallic deposit during stripping is a sign that the process is working well.
14. [ ] True or [ ] False: An oily residue floating on the surface is cause for stopping the stripping process.
15. [ ] True or [ ] False: Before re-plating a part it will most likely require activation of the surface before the plating current is applied.
AESF Foundation Training Course:
Electroless Deposition,
Lesson 12: Electroless Copper, Review Quiz:
1. [ ] True or [ ] False: Due to the build-up of reactionary by-products, electroless copper solutions based on formaldehyde reducing agent require frequent decanting and replacement of key ingredients.
2. [ ] True or [ ] False: Formaldehyde is consumed by the E-Cu process, even when the solution is not being used for plating.
3. [ ] True or [ ] False: E-Cu deposits are denser and less porous than typical electroplated copper deposits.
4. [ ] True [ ] False: Formaldehyde reduced copper plating solutions require frequent monitoring of formaldehyde and hydroxide concentration, independent of corrections made via concentrate bleed-feed.
5. [ ] True [ ] False: A key function of the stabilizers in E-Cu solutions containing formaldehyde is the prevention of the formation of Cu+2, which can yield the production of copper particulates in the plating solution.
6. [ ] True [ ] False: In E-Cu solutions containing formaldehyde, excessive loading and insufficient loading can affect the formaldehyde and hydroxide concentrations over time.
7. A critical operational parameter for E-Cu solutions containing formaldehyde and related to plating speed is:
_____a. Correct freeboard
_____b. Correct tank material
_____c. Correct temperature
_____d. None of the above
8. [ ] True [ ] False: Some formaldehyde reduced E-Cu solutions are benefitted by air agitation, while others are harmed by it.
9. The impact of low complexer concentration in E-Cu solutions containing formaldehyde is
_____a. solution turning blue
_____b. formation of copper hydroxide solids
_____c. formation of copper sulfate
_____d. None of the above
10. E-Cu solutions containing formaldehyde typically contain stabilizers at concentrations ranging from:
_____a. 1-100 g/L
_____b. 1-100 ppm
_____c. 1-100 oz/gal
_____d. None of the above
AESF Foundation Training Course:
Electroless Deposition,
Lesson 13: Electroless Au, Co, Review Quiz:
1. The main reason for use of electroless gold is __________________________.
2. Contamination of EAu by certain transition metals results in _____________________________.
3. What are two limitations on electroless gold plating processes?
__________________________________________________________________
___________________________________________________________________
4. What reducing agents are used in electroless gold plating?
__________________________________________________________________
___________________________________________________________________
5. The borohydride reduced electroless gold process is incompatible with these three things:
___________________________________________ ____________________________________
__________________________________________
6. Name three ways to speed up a borohydride reduced electroless gold process.
___________________________________________ ____________________________________
__________________________________________
7. In the borohydride E-Au process, what is the optimum concentration of Au? __________________
8. [ ] True [ ] False: All E-Au plating solutions contain gold as the cyanide complex?
9. [ ] True [ ] False: All E-Co-P plating solutions are alkaline ammonia based.
10. [ ] True [ ] False: E-Co-B plating solutions can be plated from acidic solutions.
AESF Foundation Training Course:
Electroless Deposition,
Lesson 14: Plating Plastic, Review Quiz:
1. To produce bonding sites, plastics must be ____________ prior to activation.
2. Stresses in the plastic, when plated can result in ___________________.
3. What acid is used to detect stress in plastics?
4. [ ] True [ ] False: Activators are tin/palladium complexes and colloids stabilized by excess stannous chloride
5. What color change in the plastic indicates that an activator is functioning.
6. What are two uses for pre-dips in the preparation of plastic for plating?
7. [ ] True [ ] False: Etchants change a plastic surface from hydrophilic to hydrophobic.
8. When ABS is etched the ____________________ is etched out of the surface.
9. [ ] True [ ] False: Neutralizing solutions are used after etchants to adjust the pH or the surface of the plastic (ABS).
10. [ ] True [ ] False: Pre-activators may change the charge on the surface of ABS.