Lectures 9-10

Question 1

Diffusion layers are usually present in the – depth, in surface processing

Answer 1

μm

Question 2

Coasting layers are usually present in the – to – depth in surface processing

Answer 2

nm to mm

Question 3

Surface coatings (surface processing) is when

Answer 3

a layer of coating is applied to a material to protect the surface

Question 4

Industrial cleaning can come in two different catergories of —— cleaning and —— cleaning

Answer 4

Chemical and mechanical

Question 5

Few reasons why cleaning of parts is necessary

Answer 5

• Prepare surfaces for subsequent processing
• Improve hygiene conditions for workers
• Remove contaminants that may chemically react with the surface
• Enhance appearance of product
• Restoration

Question 6

Few factors needing to be considered when selecting a cleaning method

Answer 6

• Contaminant present
• Required degree of cleanliness
• Substrate material used on the surface
• Environmental and safety factors
• Size and geometry of the part
• Production and cost requirements

Question 7

Alkaline cleaning is usually used on —— surfaces to remove …

Answer 7

metallic surfaces to remove wax, grease, oil and other particles stuck to the surface

Question 8

Solvent cleaning is usually effective on —- and —–, using ——- ——-

Answer 8

oil and grease, organic solvents

Question 9

Acid cleaning is used to remove —- and —– —- from metal surfaces

Answer 9

oils and light oxides

Question 10

Acid cleaning solutions are

Answer 10

an acid solution usually mixed with water or …..

Question 11

Acid pickling compared to acid cleaning is different in three ways.

Answer 11

• Temperature
• Acid concentration/strength
• Time immersed

Question 12

Ultrasonic cleaning is carried out by

Answer 12

agitation of a cleaning solution that is applied to a compoennt and high frequency waves allow for vibrations of the solution which results in cleaning

Question 13

Blast finishing is when

Answer 13

media is propelled at the target surface by pressurised air

Question 14

Shot peening is when a

Answer 14

high velocity stream of small cast steek pellets are fired directly at a surface

Question 15

Shot peening allows the surface of the material to improve in —— as well as improve its ——

Answer 15

strength, appearance

Question 16

Tumbling is when a barrel is spun and the parts in side the barrel are cleaned by

Answer 16

a media that landsides within the barrel as it rotates