The purpose of scientific thought is to predict what will happen in given experimental circumstances...
Download
1 / 28

the purpose of scientific thought is to predict what will happen in given experimental circumstances. all the philosoph - PowerPoint PPT Presentation


  • 157 Views
  • Uploaded on

The purpose of scientific thought is to predict what will happen in given experimental circumstances. All the philosophical discussion is an evasion of the point. – Feynman. Last class - More corrosion - micro cells Welding HAZ Sensitization Ol' Harold's story. Today -

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'the purpose of scientific thought is to predict what will happen in given experimental circumstances. all the philosoph' - Jims


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

The purpose of scientific thought is to predict what will happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

– Feynman


Last class - happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

More corrosion - micro cells

Welding HAZ

Sensitization

Ol' Harold's story

Today -

Suppressing corrosion

Corrosion examples


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Components of a cell:

anode

cathode

electrolyte

connection


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Occlude electrolyte - coatings

asphalt

greases, oils

paints

polymers

ceramic coatings

"noble" metals


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Occlude electrolyte - coatings

"noble" metals:

unless scratch

heals, a galvanic

cell is set up


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cathodic protection

galvanizing:

Zn coating applied by

hot-dipping

electroplating


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cathodic protection

galvanizing:

presence of

scratch does not

promote corrosion

of protected metal

but steel helps Zn corrode


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cathodic protection

set up cell by adding

metal which is

more anodic than

metal or alloy to

be protected


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cathodic protection

example:

protecting ship plate


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cathodic protection

example:

protecting hot water heater tanks


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cathodic protection

Problem:

steel fermentation tank in brewery

sacrificial anodes add metallic ions to electrolyte


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cathodic protection

Different approach:

Impose a voltage across cell formed by tank (cathode) and an inert anode

choice of anode material:

very inert material like Pt

but oxygen gas produced at anode


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cathodic protection

Different approach:

Impose a voltage across cell formed by tank (cathode) and an inert anode

choice of anode material:

use carbon - inert

C + O2  CO2


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cathodic protection

"…..join in a planned discussion of whether it is best to use copper tubing coils or stainless steel tubing coils inside of a stainless steel beer fermenter, the coils being used as a chiller? There has been a discussion in another brewing forum about competing concerns between the two, i.e., copper conducts heat better and is easier to bend, versus copper will slowly dissolve in the acidic environment of beer"


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Use passivated materials

Ni - NiO

Ti - TiO2

Al - Al2O3

COR-TEN:

0.19% C

0.30% Cu

0.40% Ni

0.50% Cr

0.05% V


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Anodizing

Al & other materials can be anodized

very thick oxide coating formed (8-50 microns)


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

2300x

540x

Thinking again of noble metal coatings, what about Cr plating?

Cr plating usually filled w/ microcracks due to stresses in plating


Suppressing corrosion happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Cr plating frequently a series of layers


Corrosion examples in shuttle mat'ls happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

60x

1x

235x

1180x


Corrosion examples in shuttle mat'ls happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.


Corrosion examples in shuttle mat'ls happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.


Corrosion examples in shuttle mat'ls happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.


Corrosion examples in shuttle mat'ls happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.


Corrosion area effect happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Area effect:

large cathode & small anode -

corrosion accelerated

electrochemical cell current density high

try to keep potential anodic areas large relative to cathode


Polymers - the nightmare begins happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

I am inclined to think that the development of polymerization is, perhaps, the biggest thing that chemistry has done, where

it has the biggest effect on

everyday life

LORD TODD

President of the Royal

Society of London


What are polymers? happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Why important ?

  • Long chain molecules

  • Extraordinary range of

  • physical properties

  • Many (not all) are cheap

  • Low densities


Assignment: happen in given experimental circumstances. All the philosophical discussion is an evasion of the point.

Review today's classnotes

a. coatings

b. cathodic protection

c. passivation

d. anodizing

e. Cr plating

f. corrosion examples

g. area effect

h. what is a polymer?

Read: pp 569-585, 589-591, chapter 14


ad