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{
"metadata": {
"name": "CH17"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 17: Corrosion and Degradiation of Materials"
]
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 17.1 Page No 629"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Determination of Electrochemical Cell Characteristics\n",
"\n",
"#Given\n",
"V_Cd=-0.403 #Half Cell Potential of Cd++|Cd\n",
"V_Ni=-0.250 #Half Cell Potential of Ni++|Ni\n",
"\n",
"#calculation\n",
"dV=V_Ni-V_Cd\n",
"C_Ni=10**-3\n",
"C_Cd=0.5\n",
"n=2 #Net electron exchange in Redox reaction\n",
"V=-dV-(0.0592*math.log10(C_Ni/C_Cd)/n)\n",
"\n",
"#Result\n",
"print\"Standard Cell potential is \",dV,\"V\"\n",
"print\"Net EMF is \",round(V,3),\"V\"\n",
"if V<0:\n",
" print\"Ni is reduced & Cd is oxidised\"\n",
"else:\n",
" print\"Cd is reduced & Ni is oxidised\"\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Standard Cell potential is 0.153 V\n",
"Net EMF is -0.073 V\n",
"Ni is reduced & Cd is oxidised\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 17.2 Page No 637"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Rate of Oxidation Computation\n",
"\n",
"#Given\n",
"#Activation polarisation data for Zn\n",
"VZn_Zn2=-0.763\n",
"iZn=10**-7\n",
"beta_Zn=0.09\n",
"#For H2\n",
"iH2=10**-10\n",
"VH_H2=0\n",
"beta_H2=-0.08\n",
"\n",
"#calculation\n",
"#Part i\n",
"ic=10**((VH_H2-VZn_Zn2-(beta_H2*math.log10(iH2))+(beta_Zn*math.log10(iZn)))/(beta_Zn-beta_H2))\n",
"n=2 #Exchange of 2 electrons\n",
"F=96500 #Faradays constant\n",
"r=ic/(n*F)\n",
"#Part ii\n",
"Vc=VH_H2+(beta_H2*log10(ic/iH2))\n",
"\n",
"#Result\n",
"print\"i) Rate of oxiadation is\",round(r,12),\"mol/cm**2-s\"\n",
"print\"ii) Corrosion potential is\",round(Vc,3),\"V\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"i) Rate of oxiadation is 6.18e-10 mol/cm**2-s\n",
"ii) Corrosion potential is -0.486 V\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|
