Lecture 7 Flashcards
Corrosion
A passive surface oxide film within the human body environment provide some measure of corrosion resistance
Wear
smooth and hard surface is targeted when lubricated conditions
Cell adhesion
rough surface enable better cell anchorage, bioactive coating promote cell proliferation and better tissue in-growth
Sharp spikes, deep pits, or general isotropy may all yield
the same average roughness value
Ra makes no distinction between ___ & ___, nor ___
peaks and valleys, nor does it provide information about spatial structure
3D data can highlight large data trends, such as _____ and features such as ____
waviness or lay,
predominance of ridges or scratches, that a 2D trace cannot show
Metals like Ti or Ti alloy are considered ___, and therefore need ___
bioinert, Surface treatments and coatings
Morphological Structuration
chemically etched, machined, grit blasting, laser texturing and cell adhesion
Problem w/ grit blasting
abrasive embedment
Surface Modification and Coatings Technologies
SMCT
thermal, mechanical, or thermo-mechanical treatment. Wet and dry environments
Thin TiO2 coatings on Ti-based alloys are
better protective against
corrosion in liquid environment
Thick coatings are administered by
thermal spraying, plasma spraying
Ti Plasma VPS
Prevent Ti oxidation
achieve highly porous architecture to
favor ingrowth of new bone
good adhesion
Latest developments of plasma spray
- PEEK coated by Porous Ti
* Forming of Ti scaffold
Ti spheres (100-500μm) are agglomerated by
hot pressing and sintering
Intra-lamellar cracks / fine grains due
to
high cooling rate
What is an amorphous phase?
any noncrystalline solid in which the atoms and molecules are not organized in a definite lattice pattern
Adhesion test
- main standard test in industry
* overall assessement of coating adhe
adhesion =
F(rupture)/S
