This document summarizes a study on the corrosion of magnesium and its alloys for biomedical applications. The objectives were to optimize the gas mixture in Hank's solution to obtain pH 7 and study corrosion effects when immersed with and without added protein. Various techniques were used, including immersion testing magnesium alloys in Hank's solution with controlled bubbling of CO2 and air gases. The results found that bubbling CO2 maintained pH at 7, AZ91 alloy had a higher corrosion rate than HP magnesium due to galvanic corrosion from different phases, and adding protein lowered the corrosion rate. In conclusion, the study helped understand applying magnesium alloys in biomedicine by measuring corrosion rates and examining microstructure changes after

1. By
DINI DAYANA BINTI MUSTAFFA KAMAL
(KEB110010)
CORROSION OF MAGNESIUM AND
ITS ALLOYS FOR BIOMEDICAL
APPLICATIONS
Supervised by
DR NOR ISHIDA BINTI ZAINAL ABIDIN

2. Magnesium
Good
mechanical
properties
Biocompatible
Has ability to
biodegrade
Chosen as biomedical
implants
• Light
weight
• Good
strengt
h
• Non toxic
• Mg ions
present in
bone
• Degrade
biological
ly in
solution
CORROSION
!

3. Objectives
 To optimize the gas mixture of
compressed air and carbon dioxide
(CO₂) in Hank’s solution to obtain
pH 7
 To study the corrosion effects on
magnesium and its alloys when
immersed in Hank’s solution, with
and without addition of protein

4. Corrosion
Mg(s) +H₂O(aq) ↔ Mg(OH)₂(s) +
H₂(g)
Corrosion
products
Why need to control the corrosion
rate?
• Implants can function in the required
period of time in human body
• To maintain its mechanical integrity in
order to effectively serve its purpose
• Prevent toxication in human body

5. In vitro
• Procedure
performed in a
controlled
environment
• Immersion test
In vivo
• Experimentation
using a whole,
living organism
• Animal test
Techniques used to determine
corrosion rate

6. Methodology

7. Type of gas
Scale reading
(flowmeter) Flowmeter (ml/min) % of gas Time (min) pH readings
CO2 2 141.8 12.4
Initial 7.92
30 min 6.18
60 min 6.25
Air 32 1001 87.6
90 min 6.24
120 min 6.25
CO2 1 70.9 6.6
Initial 8.19
30 min 6.27
60 min 6.27
Air 32 1001 93.4
90 min 6.29
120 min 6.33
CO2 4.3 304.87 83.4
Initial 8.25
30 min 5.45
60 min 5.53
Air 3 60.6 16.6
90 min 5.51
120 min 5.64
CO2 1 70.9 41.2
Initial 8.29
30 min 5.69
60 min 5.69
Air 5 101 58.8
90 min 5.73
120 min 5.78
CO2 1 70.9 15.4
Initial 8.2
30 min 6.86
60 min 6.01
Air 15 389 84.6
90 min 6.02
120 min 6.14
C02 1 70.9 11.0
Initial 7.82
30 min 6.18
60 min 6.2
Air 20 576 89.0
90 min 6.14
120 min 6.13
Results & Discussion- Obj 1

8. Results & Discussion- Obj 2

9. HP Mg without
protein
HP Mg with protein
AZ91 without protein AZ91 with protein
EDS Analysis before corrosion product removal

10. Microstructure of Mg Alloys after
corrosion product removal

11. Material Specimen PW (mm/y)
HPMgwoP 1 4.207
2 5.986
HPMgwP 1 0.557
2 0.575
AZ91woP 1 0.965
2 1.533
AZ91wP 1 3.535
2 7.167
Corrosion rate measurement using
weight loss

12. Recommendations
 Bubbling CO₂ gas into the solution had maintained pH at 7.
 Corrosion reactions of HP Mg and AZ91 have been studied.
AZ91 has higher corrosion rate as it has different phases in its
microstructure, leading for galvanic corrosion to occur.
 Effects of addition of protein to the Hank’s solution have been
determined. Protein had caused the corrosion rate to be lower.
 Corrosion rate measurements and microstructure studies helped
in understanding the application of magnesium alloys in
biomedical.
Conclusion
 Ensure there is no leaking of gas during the bubbling of CO₂ gas
into Hank’s solution.
 Experimental set up should be checked regularly in order to
avoid faulty in data collections.
 Proper cleaning of immersed specimens must be done to
remove all corrosion product

13. Thank you