早餐喝橙汁的机器，你投入新鲜的橙汁，直接挤压，从左边出来是轧完的橙子，中间流入杯子是新鲜的橙汁，奢侈的新鲜

德国Helmholtz-Zentrum Geesthacht的博士后的广告，很不幸的是不要材料专业的

本日下午是去Cilento National Park: Morigerati and Sicili，没有学术报告

Session 3: Corrosion

Time Title PresenterAffiliation Page

08:30-09:00 K2- Influence ofcorrosion on mechanical properties of Mg5Gd wire P. Maier

University of AppliedSciences Stralsund,

Germany

Cor-1

Wire of Mg-alloys itself are rarely discussed in literature

Possible wire application: Kirscher wires

Prebending to fit contour

Wire 1.6mm

Extrusion

Solution heat treatment at 500 degree for 6h

Drawing at 350 degree C

9 step  (each step with thedeformation of 30%)

Finalized by anneal 470 degree  Cfor15 min

Grain size -20micrometer

Second phase Gd-rich (37.5wt%)

Gd-particles of 80wt.%Gd are also found (formed during casting and heattreatment)

Three point bending

Span 25mm test speed 1mm/min(work hardening at 10mm/min only slightlyhigher)

Hardness: ad-cast HV 47---extruded 50---T4—46.8 ---wire drawging 62.9  (longitudinal)  68.7(cross section)

Hardness of pre-bent wires

Higher hardness increase at compression side (known for small thickness)

Outer strain -15% deflection 10 mm, internal angle <90degree

Corrosion of wires: pitting but all over the surface

Corrosion products Mg(OH)2

Over 3 days weight increase 10 mg ~10%

Some wire parts show residual stresses

Corrosion attacked mostly on tension

Elliptical pits developing into subsurface pitting corrosion

Hardly any corrosion attack on compression side even higher hardnessincrease at this side(in theory disclocation increase anodic dissolution)

Tensile stress increase corrosion forming passive layer opens up by thetensile stress

After corrosion, Ductility can be only found for the compression (evenhigher for bending), not for tension

Corrosion strongly reduces strength of the wire

Less microgalvanic corrosion and less residual stress

Correlation between pit shape/size to strength loss

Stress corrosion cracking

09:00-09:20

O14- Cyclic voltammetry for prediction of degradation ofresorbable metallic biomaterials: possibilities and limitations

W.D. Mueller

Charite UniversitaetsmedicineBerlin,

Germany

Cor-2

Discrepancies in corrosion rates between different measurements

Reliability of electrochemical testing?

Al, Fe, Zn, Mg(99.8%)

Ringer solution

Cyclic voltammogramms on Mg with different rate

1mV/S 10, 50mV/S 100 mV/S 200mV/S

H2 gas evolution, current increase

Mg2+ + 2H+ + 4e- = MgH2, pH shift

wolf-dieter.mueller@charite.de

09:20-09:40

O15- How Fe35Mn alloy stent degrade in a short-term period

H. Hermawan UniversitiTeknologi Malaysia, Malaysia Cor-3

09:40-10:00

A stent experience “excessive” plastic deformation crimping and expansion,…

0.5h, 1h 24h, 168h

Degradation proceeds on the stent surface, amount of Fe and Mn decreasewhile O increases.

Degradtion rate increase pure Fe< Fe35Mn alloy< Fe35Mn stent

O16- Methodical Screening of Corrosion Iron Alloys

P. Quadbeck IFAM, BranchLabDresden, Germany Cor-4

Low mass components

Corrosion promoting elements

Adjustment of grain size

Formation of precipitates

Fe-0.6P by mixing Fe with 3.6%Fe3P

Increased sintering activity

Fe-C 0.38, 0.49, 0.65, 0.88 %C

Intermeallic phases  precipationwith increase corrosion

Fe-9.3W Fe-20W 1300 degree C homogenized

Mn

S known to initiate pitting

Fe3MnS 590 micrometer/y

Fe 463 micrometer/y

Silicon Fe-0.5Si

Fe+FeSi45

Contact corrosion

Fe-0.6P5Ag Fe-21.3Au Fe31Ag Fe7.3Sn Fe5.9Ti

Increase corrosion by continuous phase, corrosion at phase boundaries

Carbides phosphides and intermetallic phases reduced the corrosion rate

10:30-10:50 O17- Bioactivecoatings as a key for advanced biomedical applications A. Eliezer Bialik/BaselSts. Beer-Sheva, Israel Cor-5

Most corrosion protection coatings are multi-layer systems

Proper preparation of the surface is absolutely critical to achievingaffective coating performance

The major issue driving development of corrosion protection coatingstodays is the need to meet increasingly strict regulatory requirements

Different mechanism by which bacteria can protect alloys from MIC

Corrosion change with the incubation with bacteria

Bacteria performance Biofilm

Mg-4Y

Cannulated interference screw

Corrosion Bio-reactor Cell

For uncoated sample the geometry have influence on corrosion rate, butafter coating the influence decreases.

10:55-11:00

SOP17- Comparison of the degradation behaviour of binary Mg-Agand Mg-Gd alloys in PBS and in physiological conditions

I. Marco KatholiekeUniversiteit Leuven, Belgium Cor-7

Mg-Gd (slown down)

Mg-Ag(speed up)

Pure Mg WE43 reference

PBS 37 degreeC V/S=30

5%CO2 DMEM V/S=30 37 degreeC

5%CO2 DMEM V/S=2 37 degreeC

MgCO3 Mg(OH)2 HA

11:00-11:05

SOP18- Study of magnesium fluoride and self-assembledorganosilane coatings of AZ31 and MgCa0.8 alloys

T. Hassel Leibniz UniversitätHannover, Germany Cor-8

Discharge optical emission spectroscopy

11:05-11:10

SOP19- Influence of different surface modifications of themagnesium alloy

WE43 on the electrochemicalbehaviour

C. Schille UniversityHospital Tuebingen, Germany Cor-9

To avoid the use of harmful HF, KF, NaF, NH4F, CaF2 can be used.

11:10-11:30

O18- Different approaches for invivo testing of absorbable metals inblood vessels

M. Bartosch DeutschesHerzzentrum Berlin, Germany Cor-10

Large degradable stent up to 30mmX30mm

Preselection mechanical property, cytotoxicity, hemocompatibility

Aim at establishing methods for fat and easy testing of possible stentmaterials

Different materials, process, post treatment….

Mg10Gd

Cold drawing from 6 to 40.4mm (66 pass)

Wire implantation 1,2,4,6,8 weeks

Carrier stent

Sewing Mg alloy wire on polyamide stent