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Published byJacob Franklin Modified over 6 years ago
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APPLIED POTENTIAL (V) active passive transpassive log CURRENT DENSITY
NOBLE APPLIED POTENTIAL (V) active passive transpassive log CURRENT DENSITY ip ic ACTIVE Epp EF
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Fe2O3 Fe3+ Fe2+ Fe 5 pH E Fe3O4 transpassive passive Active dissolution 2H2OO2+4H++4e- MM++e- Epp icorr ioM+/M ioH+/H2(Fe) Er,H Ecorr Er,M ip log |i| Epp EM+Z/MxOy For only those who are interested in knowing what a pourbaux diagrams looks like
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Inflammation What are the signs of Inflammation?
The inflammatory reaction is normally characterized by 5 distinct signs, each of which is due to a physiological response to tissue injury. Pain (due to chemicals released by damaged cells) Swelling or Edema (due to an influx of fluid into the damaged region) Redness (due to vasodilatation- the widening of blood vessels) Heat (due to an increase in blood flow to the area) Loss of function (due to increased swelling and pain)
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Turbostratic Stucture
A type of crystalline structure where the basal planes have slipped sideways relative to each other, causing the spacing between planes to be greater than ideal.
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Pyrolytic carbon is an isotropic turbostratic form of carbon.
The crystalline structure of pyrolytic carbon has a distorted lattice structure with random unassociated carbon atoms This structure provides it with isotropic properties (similar in all directions) It is formed by pyrolysis of a hydrocarbon gas creating random crystallization Key Properties Biocompatible Thromboresistant i.e. resists blood clotting Good durability Good wear resistance Good strength
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How is Pyrolytic Carbon ?
It is usually formed in a fluidized bed furnace The bed consists of small ceramic particles and parts to be coated A levitating gas creates required random motion of parts within the bed Heating elements raise furnace temperature to 1200° -1400°C An introduced hydrocarbon gas undergoes decomposition at these temperatures creating free carbon that recrystallizes on whatever surface it comes in contact with first
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Applications Pyrolytic carbon coatings are made by co-depositing carbon and silicon carbide onto suitable substrates using chemical vapour deposition processes. Deposition is carried out in a fluidised bed furnace, fed with silicon carrier gas and a hydrocarbon.
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