first hand investigations (1 Viewer)

[tennille]

Does anyone have information on the dot pt. "identify data, choose eequipment, plan and perform a first hand investigation to compare the corrosion rate, in a suitable electrolyte, of a variety of metals, including named modern alloys to identify those best suited for use in marine vessels". We didn't perform this experiment and I would appreciate it is someone could give me a brief description of the modern alloys used, procedure, and results obtained.

Also, for the dot pt. "identify data, select equipemtn, plan and perform a first ahnd investigation to compare the rate of corrosion of iron and an identified form of steel", what conditions were used? eg. salt water, distilled water...etc

Thanks for that.

 

[tennille]

anyone there? I dont need a detailed description.

 

[withoutaface]

Ummm, for the second one (from Macquarie)

Samples:
Iron (wrought and/or cast)
Mild steel (eg bolts)
Stainless Steel

Each sample was placed in the following different kinds of tubes:
- dry air only (use drying crystals)
- water and air present
- water only (degassed by boiling)
- salt water

The samples were left and checked each lesson, and the amounts of rusting were compared, the most rusted should be cast iron, then mild steel, then wrought iron, and then stainless steel.

First one:
In macq it doesnt give results, but here's what it has:


alloys used are stainless steel and brass
metals used are aluminium, iron, zinc, copper

Proceedure:
1. Clean all metals and alloys with steel wool
2. Place each metal flat in a petri dish, with 5% saltwater solution, so that they are partially immersed.
3. Observe and record any changes to the surfaces of each metal each lesson for several weeks.

Someone with a better knowledge of chem might be able to correct me, but the results in order from most to least corrosion sould be:

iron, copper, brass,aluminum=stainless steel. not sure about zinc

Wow, this made me realise how much I need to revise my pracs

 

[tennille]

Thank you so much for that

 

[tennille]

aluminum=stainless steel, iron, copper, brass. not sure about zinc

shouldn't that be the other way around. Aluminium and stainless steel should be the least corrosive since stainless steel has a protective chromium layer and aluminium has a protective oxide layer.

 

[withoutaface]

shouldn't that be the other way around. Aluminium and stainless steel should be the least corrosive since stainless steel has a protective chromium layer and aluminium has a protective oxide layer.

Fixed now

 

[tennille]

hehehe...