~Chapter 5~

ok kengkawan..kte start ngn chpter 5..hehe..nape chpter 5??haaa...ini kerana..diriku start
bce chpter 5 dlu..so,pale aku da set chapter 5 dlu n chpter 5 yang mule2 menapak di benak
ini..heee...cheewaaaahhh..eh..eh...silap2..

"concentrate noraini..kamu tgh nk share ilmu ngan org..jgn main2"
"ye...baik lah...."

in chpter 5 ni...kte blaja psl tafel extrapolation,polarization methods,instrumental methods
for polarization resistance ngan other methods utk determine polarization resistance ni...
as the introduction..kte kne la tau..chpter 5 ni sbnrnye nk cte psl polarization resistance..
so..ade 2 methods utk kte measure corrosion by electrochemical polarization which are tafel
extrapolation and polarization resistance..chpter ni kn nk focus pd polarization resistance..
so kte kne la tau polarization resistance tu ape...
polarization resistance ni adlh method yang..
- highly sensitive
- accelerating factors mcm elevated temp.
- method ni jgk is nondestructive..so,bley buat byk2 kali la..

first of all..psl tafel extrapolation..
tafel extrapolation ni sbnrnye was introduced to illustrate the application of mixed
potential theory to aqueous corrosion...
kalo ikot buku,die ade bg 2 reaction kn?haa...bkak balik buku..tgk..btol tak..:)
yang first equation tu psl reduction of hydrogen..rate utk reaction tu is relatively high
sbb ready availability of H plus kt ctu yang di control oleh pH..
yang rxn kedua tu plak..rate die is low and limited bcz of dissociation of water molecule..
sbnrnye kn..cathodic polarization is more rapid and reversible compared to anodic polarization.
tafel ni sbnrnye ade kt cathodic je sbb linear graf tu tak intercept ngan anodic polarization
punye graf..yang ni korg kene la tgk buku..cane aku nk tnjuk kn..heee:)

degree of polarization sbnrnye lagi tinggi utk lower corrosion rate.
polarization resistance method ni derived from mixed potential theory..
so,refer buku ek utk tgk die punye formula yg ade itu..:)

experimental methods tu ade 2..
- galvanostatic
- potentistatic/potentidynamic

1. galvanostatic
utk yang ni..current steps are apllied n nnt result die kte leh observe kt monitor.
- advantages galvanostatic ni...
- small constant current superimposed at potential chage
- potential overvoltage decays rapidly akn back to the consistent value
- polarization resistance procedure ni takkan bg effect pd potential drift.

2. potentiodynamic
- mse buat measurement ni,kne make sure corrosion potential adlh stable.
- then kne run exp ni slowly untk make sure steady state die..

methods lain plak..ade 3 lg..which are....
1. analysis of polarization curve shape
- yang ni basically gne tangents slope n intercepts
2. transient methods
- yang ni korang kne check kt buku..ade formula die bg...
3. electrochemical impedance spectroscopy (EIS)

ummm...ni je kot cket2 yang aku ingt psl chpter 5 ni...
every methods tu korang kne la tgk cket kt buku..tgk cane methods tu sbnrnye...
ok..mane2 yang kurang tu..korang bce sndiri ek..aku taip ape yg aku ingt je ni...
kalo ade yg slh...betolkn ye...thanks...semoga kte same2 bleh jwb senin ni..aminn..:)