Assalam o Alaikum Dr. Hazwan , the way you are guiding the young scientist is reallt appreciable.... I am also a young phD student and working on Mg AZ31 alloy.. Could you please provide me the guidance on following ponits related to PDP 1. Which counter electrode is better graphite or platinum 2. How to put the values of stern geary coefficient , equivalent weight , is there any standard method. 3. What should be the appropriate votlage value w.r.t OCP , i mean some people put +250 mv - 250 mv , some put +1 V -1 V ... is there any logic behind it. Best Regards
Waalaikumsalam 1. Both graphite and platinum works well as counter electrode. 2. For the equivalent weight, we understand that it is equal to Mew = Mw/n (average molecular mass of metal/valency). Therefore you need to calculate first the average molecular mass of MgAZ31 alloy based on their elemental composition. 3. Well it depends on what kind of information that you want to see. Bigger range of potential (-1 V to 1 V) is often used to study the passivation and pitting corrosion, while lower potential range (like those mentioned in the video) is used for active polarization.
Excelente video, actualmente utilizo un potenciostato Gamry Reference 3000 me encuentro terminando mi tesis estos videos me ayudan, me gustaria encontrar mas informacion o derrepente entrar a algun foro o grupo donde podamos intercambiar informacion.
Hi Dr. Mohd Hazwan Thank you for the details . I am working on nano aluminium metal matrix composite and I wanted to know 1) For PD what should be the initial and final V and the Scan Rate 2) For EIS What should be the initial freq. and final freq. and AC voltage Waiting for your valuable feedback.
@@nikhilbharat8689 ok 1) Potential range of PD can be -500 mV to 500 mV vs. Eocp. Scan rate can be 0.5 mV/s to 1 mV/s 2) Recommended frequency range can be 10kHz to 0.1 Hz and AC voltage can be 10 mV
Thank you very much to presentaiton Mr Hazwan. As i understand, it is possible to measure corrosion rate of coated steels. I have some coated steels which are coated with pet,pvc, etc. Can i use same set up logic for our coated materials? and will i see corrosion rate of our materials in same table which is at 18:10 in your video?
True, inspection for corrosion under insulation (CUI) is sometimes tricky. Nevertheless, you still can undergo polarization measurement for coated samples in order to get the corrosion current density, icorr or even corrosion rate. Remember to remove some part of the coatings so that working electrode cable can be clipped directly to the substrate.
Great video .. Can I ask about using different concentrations of the inhibitor.. do you have to polish working electrode before each concentration? Or is it sufficient to polish once in the beginning when the lowest amount is used?
Hi Dr, i have several questions regarding this corrosion testing 1. For the reference electrode, is it mandatory to use SCE? can we use Ag/AgCl instead? and if we can use Ag/AgCl instead, will there be any difference in the method as shown by your video 2. Does analysing using the potentiostat is used directly after immersing the corrosion object (working electrode) in the cell, or do we need to wait for several times? and will there be any difference if we immerse it first for 3 hours and then analysing using the potentiostat?
@@027-delondavidson-sithr2 Hi there, 1. Yes you can use Ag/AgCl electrode or even silver wire as long as it functions as a reference electrode 2. Well it depends on the nature of analysis that you wanted to do. Normally electrochemical analysis are done after we obtained the steady state potential from OCP analysis. But in case of you wanted to study the corrosion rate at different immersion time, it will be a different sequence
Hello Sir, I want to ask that , by definition anodic beta taefel constant and cathodic beta constants are the volts/decade .... But my confusion is which decade we have to obsevrve ? there are more than one decades on x-axis (log current density)
Well, ba and bc are basically the slopes of anodic and cathodic polarization curves. No doubt it is the potential over current relation but the equivalent unit is also equals to potential over decade
Thank you for the informative video. I want to figure out polarization resistance for a reinforced concrete setup. My cable connection is fine. But when I perform Polarization resistance measurement, the current is around pico ampere. my OCP is around -535mV. How can I correct my current data?
@@suraksha56 please recheck your counter electrode..try with simple graphite electrode or if you have another counter electrodes like platinum or stainless steel
Hello Dr. Hazwan, I’m curious, do you have to always polish before running corrosion experiments? Would cleaning with distilled water and acetone be okay? Thanks for a great video. I look forward to what you have to say. Sincerely, Richard
Hi Richard, The main purpose of polishing is to get rid of any impurities (for instance oxide layer that may form) that may increase the surface resistance. By principle, to get a sensible value of electrochemical parameters, it is best to do the surface pretreatment (polishing) before running the experiment.
Hello Dr. Hazwan, I ran a steel test. It went very well. Do you have any advice on how I can work with aluminum alloy? When running potentiodynamic polarization I always get noisy signals near Eoc. I’m using 2000 SiC to polish the aluminum working electrode. I sonicate 15 minutes each with acetone followed by a quick rinse with DI water and finally sonicate with DI. Electrolyte contains sodium chloride, and potassium sulfate when running PDYN on Gamry. Any help would be truly fantastic.
@@richardwest4567 dear Richard, is there any bubbles formed on the aluminum surface? If yes, perhaps you can purge it first using a dropper before running the polarization
@@mohdhazwan6523 Hi Dr. Jazwan, thanks for getting back to me. There is no bubbles before beginning the polarization experiment. I run it from -50 mV to + 50 mV vs Eoc and no bubbles. However, if I push well beyond +50 mV the Eoc I will see it.
good explanation! I am a freshman in the corrosion field and I'm been working for several months on metal corrosion experiments. yet I can't repeat my data for once. So confused and frustrated! May I have your email so I can introduce you to more details and the data? Thank you so much!!!
Thank you. You can check my email address from this link chem.usm.my/index.php?option=com_content&view=article&id=80:dr-lee-hooi-ling&catid=17:academic&Itemid=272
Greetings, This was a very informative video for great visual understanding. I would like to know if it's possible to measure the corrosion rate for reinforced cement concrete in the field of Civil Engineering. Thank You.
Assalammualaikum Dr Hazwan. I'm Asiah, PhD student, working on piezoelectric material. I want to obtain current response graph, to switch on/off event using electrochemical method (Metrohm). Could you guide me to setup the procedure, either to select LSV or chronoamperometry setup in the AUTOLAB software? I use Na2SO4 as electrolyte, reference electrode : standard calemel electrode (SCE), counter electrode: Platinum electrode. Thank you.
Hi Mohd, I am working on welding of austenitic stainless,inconel and dissimilar welding. What are the different electrochemical corrosion test, I can perform.
Hi, you can perform both polarization and impedance. But in order to calculate the corrosion rate of your welding metals, you need to know the elemental composition of the alloy.
Assalamualaikum Dr..may I ask you Dr regarding corrosion inhibition studies? Currently I'm doing corrosion inhibition studies (EIS & POLARIZATION) using Autolab NOVA 2.1.4..according to the theory, as the concentration of inhibitor increases, the semicircle in EIS supposedly to be increased..however, the data obtained is fluctuate & inconsistent (not follow the rules)..does the geometries, distance & position between WE, RE & CE can affect the data? Or it is because the working electrode is not consistently polished? And may I have the suggestion to minimize this problem?
Waalaikumsalam Alia, There are many reasons for scattered points of EIS data; 1. The experimental set up is not suitable 2. Formation of bubbles on the surface of your WE 3. RE or CE are not working well 4. Cables are not properly connected to the cell 5. Leaking from the electrolyte 6. Noise disturbance from the environment. What is the type of metal that you used as WE? What is the Eocp value? From here we can deduced something, either the problem is coming from RE or connection.
@@mohdhazwan6523 Thank you so much Dr for your explaination..for your information the material been used is mild steel & Eocp value obtained around -0.474V
@@aliaatiqah4829 RE seems ok because it measures the actual range of iron standard potential. Is there any hydrogen gas bubbles on the surface of your WE? If there is, I would recommend you to remove the bubbles using dropper (flushing on the surface) after OCP just before EIS measurement
Thank you for your question. The corrosion inhibitor was added in the solution media via dilution. Let say 100 ppm (100 mg/L) of inhibitor in 0.5 M HCl, we weighed first 100 mg of inhibitor and later dilute it with 0.5 M HCl for 1 L volume. You can scale it done (depends on how much sample you have) like to 100 mL (weigh only 10 mg instead of 100 mg).
Good question. If you want to monitor the stability of your potential, you can switch it on and perform open circuit potential. The outcome will be a profile of your metal's potential over time.
not literally the same. PDP plots are logarithmic version of current density, while LPR plots are linear version of current density. The potential range between these two methods are not the same as well. PDP have slightly bigger range than LPR.
@@chuaalvin7455 well there is a lot of references available. For PDP the potential range is normally around +-300 mV or +-250 mV from Eocp, while for LPR the potential range is around +-20 mV only from Eocp.
Hi Mr Mohd, if I want to measure the corrosion rate for coating application using this method, do I need to apply coating on both side of the sample? Or 1 side is enough?
Hi Ahza, for this method one specific exposed area is enough. Corrosion rate use electrochemical technique can be calculated as follows: CR (mpy) = (0.13 x icorr x Mew)/density Where icorr must be in microamperes, Mew is the equivalent weight (atomic mass/valency) and density is the density of the studies metal
Hi Mohd, I would love to speak with you in order to better understand the different methods I could use to corrosion test my stainless steel. Would you be open to a zoom call? I’m in Orlando, Florida, so I would be on EST time
Hi i m new researcher n i m going to work on corrosion inhibition but can u please suggest me which electrochemical machine is very good for corrosion inhibition study
Oh well, all potentiostats have the same purpose. I have been working with different types of potentiostats and found that each potentiostats have its own uniqueness. To me, it doesn't matter which brand you are working with, the most important thing is the consistency and the ease of setting. That's all
Thanks Dr. Hazwan for the video, interesting one. I want to measure the corrosion rate of two metals (Titanium and Aluminium) in FeCl2/HCL/KCL solutions. Would you be able to help me to do the experimental set-up. That would be nice If I can have your email address, please.
Dear John, you can dissolve the pcm first with small amount of ethanol and later dilute it with the electrolyte of interest (distilled water or brine or acid solution). Remember solubility is crucial for corrosion inhibition studies.
@@gyaniyumnam7266 this is the old version. Most of Gamry 600 has been upgraded to Gamry Reference 600+. The price is almost the same as mentioned earlier
Amazing, thanks for sharing!
Thanks!
very nice and informative video
Thank you
very helpful. thank you!
Assalam o Alaikum
Dr. Hazwan , the way you are guiding the young scientist is reallt appreciable....
I am also a young phD student and working on Mg AZ31 alloy..
Could you please provide me the guidance on following ponits related to PDP
1. Which counter electrode is better graphite or platinum
2. How to put the values of stern geary coefficient , equivalent weight , is there any standard method.
3. What should be the appropriate votlage value w.r.t OCP , i mean some people put +250 mv - 250 mv , some put +1 V -1 V ... is there any logic behind it.
Best Regards
Waalaikumsalam
1. Both graphite and platinum works well as counter electrode.
2. For the equivalent weight, we understand that it is equal to Mew = Mw/n (average molecular mass of metal/valency). Therefore you need to calculate first the average molecular mass of MgAZ31 alloy based on their elemental composition.
3. Well it depends on what kind of information that you want to see. Bigger range of potential (-1 V to 1 V) is often used to study the passivation and pitting corrosion, while lower potential range (like those mentioned in the video) is used for active polarization.
@@mohdhazwan6523 Really thankful
Excelente video, actualmente utilizo un potenciostato Gamry Reference 3000 me encuentro terminando mi tesis estos videos me ayudan, me gustaria encontrar mas informacion o derrepente entrar a algun foro o grupo donde podamos intercambiar informacion.
Gracias
Very interesting, thank you Dr. ☺
Thank you Tahir
Hi
Dr.
Mohd Hazwan
Thank you for the details . I am working on nano aluminium metal matrix composite and I wanted to know
1) For PD what should be the initial and final V and the Scan Rate
2) For EIS What should be the initial freq. and final freq. and AC voltage
Waiting for your valuable feedback.
Hi Nikhil, before I answer your questions may I know what is the medium (electrolyte) that will be used to test your aluminium metal?
@@mohdhazwan6523 Dear Hazwan it is NaCl
@@nikhilbharat8689 ok
1) Potential range of PD can be -500 mV to 500 mV vs. Eocp. Scan rate can be 0.5 mV/s to 1 mV/s
2) Recommended frequency range can be 10kHz to 0.1 Hz and AC voltage can be 10 mV
@@mohdhazwan6523 Thank you so much for your help. I appreciate your work
Thank you very much to presentaiton Mr Hazwan. As i understand, it is possible to measure corrosion rate of coated steels. I have some coated steels which are coated with pet,pvc, etc. Can i use same set up logic for our coated materials? and will i see corrosion rate of our materials in same table which is at 18:10 in your video?
True, inspection for corrosion under insulation (CUI) is sometimes tricky. Nevertheless, you still can undergo polarization measurement for coated samples in order to get the corrosion current density, icorr or even corrosion rate. Remember to remove some part of the coatings so that working electrode cable can be clipped directly to the substrate.
Great video .. Can I ask about using different concentrations of the inhibitor.. do you have to polish working electrode before each concentration? Or is it sufficient to polish once in the beginning when the lowest amount is used?
Yes polishing is mandatory to the working electrode before any electrochemical testing
Hi Dr, i have several questions regarding this corrosion testing
1. For the reference electrode, is it mandatory to use SCE? can we use Ag/AgCl instead?
and if we can use Ag/AgCl instead, will there be any difference in the method as shown by your video
2. Does analysing using the potentiostat is used directly after immersing the corrosion object (working electrode) in the cell, or do we need to wait for several times? and will there be any difference if we immerse it first for 3 hours and then analysing using the potentiostat?
@@027-delondavidson-sithr2 Hi there,
1. Yes you can use Ag/AgCl electrode or even silver wire as long as it functions as a reference electrode
2. Well it depends on the nature of analysis that you wanted to do. Normally electrochemical analysis are done after we obtained the steady state potential from OCP analysis. But in case of you wanted to study the corrosion rate at different immersion time, it will be a different sequence
@@mohdhazwan6523 Thanks a lot Dr.!
@@mohdhazwan6523 Also, i would like to ask more questions
for the corrosion test, do we need salt bridge?
@@027-delondavidson-sithr2 if you use reference electrode that contains porous separator or with Luggin capillary, you don't need the salt bridge
@@027-delondavidson-sithr2 if you use reference electrode that contains porous separator or with Luggin capillary, you don't need the salt bridge
Hello Sir,
I want to ask that , by definition anodic beta taefel constant and cathodic beta constants are the volts/decade .... But my confusion is which decade we have to obsevrve ? there are more than one decades on x-axis (log current density)
Well, ba and bc are basically the slopes of anodic and cathodic polarization curves. No doubt it is the potential over current relation but the equivalent unit is also equals to potential over decade
Thank you for the informative video. I want to figure out polarization resistance for a reinforced concrete setup. My cable connection is fine. But when I perform Polarization resistance measurement, the current is around pico ampere. my OCP is around -535mV. How can I correct my current data?
And your sample is stainless steel?
@@mohdhazwan6523 no it is normal carbon steel used to make rebar
@@suraksha56 please recheck your counter electrode..try with simple graphite electrode or if you have another counter electrodes like platinum or stainless steel
Hello Dr. Hazwan,
I’m curious, do you have to always polish before running corrosion experiments? Would cleaning with distilled water and acetone be okay? Thanks for a great video. I look forward to what you have to say.
Sincerely,
Richard
Hi Richard,
The main purpose of polishing is to get rid of any impurities (for instance oxide layer that may form) that may increase the surface resistance. By principle, to get a sensible value of electrochemical parameters, it is best to do the surface pretreatment (polishing) before running the experiment.
@@mohdhazwan6523 thank you very much for replying back so quickly and over the weekend. I really appreciate it and thank you for the advice.
Hello Dr. Hazwan, I ran a steel test. It went very well. Do you have any advice on how I can work with aluminum alloy? When running potentiodynamic polarization I always get noisy signals near Eoc. I’m using 2000 SiC to polish the aluminum working electrode. I sonicate 15 minutes each with acetone followed by a quick rinse with DI water and finally sonicate with DI. Electrolyte contains sodium chloride, and potassium sulfate when running PDYN on Gamry. Any help would be truly fantastic.
@@richardwest4567 dear Richard, is there any bubbles formed on the aluminum surface? If yes, perhaps you can purge it first using a dropper before running the polarization
@@mohdhazwan6523 Hi Dr. Jazwan, thanks for getting back to me. There is no bubbles before beginning the polarization experiment. I run it from -50 mV to + 50 mV vs Eoc and no bubbles. However, if I push well beyond +50 mV the Eoc I will see it.
good explanation! I am a freshman in the corrosion field and I'm been working for several months on metal corrosion experiments. yet I can't repeat my data for once. So confused and frustrated! May I have your email so I can introduce you to more details and the data? Thank you so much!!!
Thank you. You can check my email address from this link chem.usm.my/index.php?option=com_content&view=article&id=80:dr-lee-hooi-ling&catid=17:academic&Itemid=272
Greetings,
This was a very informative video for great visual understanding.
I would like to know if it's possible to measure the corrosion rate for reinforced cement concrete in the field of Civil Engineering.
Thank You.
Hi, yes it is possible to calculate corrosion rate for reinforced steel. But the set up is not the same as shown in this video
Assalammualaikum Dr Hazwan. I'm Asiah, PhD student, working on piezoelectric material.
I want to obtain current response graph, to switch on/off event using electrochemical method (Metrohm). Could you guide me to setup the procedure, either to select LSV or chronoamperometry setup in the AUTOLAB software?
I use Na2SO4 as electrolyte, reference electrode : standard calemel electrode (SCE), counter electrode: Platinum electrode.
Thank you.
Dear Asiah, unfortunately I dont have Autolab unit in my lab
Hi Mohd, I am working on welding of austenitic stainless,inconel and dissimilar welding. What are the different electrochemical corrosion test, I can perform.
Hi, you can perform both polarization and impedance. But in order to calculate the corrosion rate of your welding metals, you need to know the elemental composition of the alloy.
Assalamualaikum Dr..may I ask you Dr regarding corrosion inhibition studies? Currently I'm doing corrosion inhibition studies (EIS & POLARIZATION) using Autolab NOVA 2.1.4..according to the theory, as the concentration of inhibitor increases, the semicircle in EIS supposedly to be increased..however, the data obtained is fluctuate & inconsistent (not follow the rules)..does the geometries, distance & position between WE, RE & CE can affect the data? Or it is because the working electrode is not consistently polished? And may I have the suggestion to minimize this problem?
Waalaikumsalam Alia,
There are many reasons for scattered points of EIS data;
1. The experimental set up is not suitable
2. Formation of bubbles on the surface of your WE
3. RE or CE are not working well
4. Cables are not properly connected to the cell
5. Leaking from the electrolyte
6. Noise disturbance from the environment.
What is the type of metal that you used as WE? What is the Eocp value? From here we can deduced something, either the problem is coming from RE or connection.
@@mohdhazwan6523 Thank you so much Dr for your explaination..for your information the material been used is mild steel & Eocp value obtained around -0.474V
@@aliaatiqah4829 RE seems ok because it measures the actual range of iron standard potential. Is there any hydrogen gas bubbles on the surface of your WE? If there is, I would recommend you to remove the bubbles using dropper (flushing on the surface) after OCP just before EIS measurement
can you show galvanostatic charging and discharging demonstration
Hello, few people have asked me the same thing. Unfortunately our potentiostat system did not come with a charge discharge software
Hi dr, i would like to ask how the process of adding inhibitor at the end of your video? Is it just adding into the electrolyte?
Thank you for your question. The corrosion inhibitor was added in the solution media via dilution. Let say 100 ppm (100 mg/L) of inhibitor in 0.5 M HCl, we weighed first 100 mg of inhibitor and later dilute it with 0.5 M HCl for 1 L volume. You can scale it done (depends on how much sample you have) like to 100 mL (weigh only 10 mg instead of 100 mg).
Sir, can I get your email to ask regarding GAMRY instruments? I am doing my fyp in my university but my university didnt have GAMRY
@@nurkhuzaimah1602 you can check it out from my profile at chem.usm.my directory
I want to know while we are buying that gamry that white one i.e for keeping mild steel sample, will also come together or what??
Do you mean the cell? No it is not. That cell i have fabricated it but you can also use a beaker as a simple electrochemical cell
Hi Mr Mohd, if i want to immerse the material in the solution for 3 hours first, do i have switch on the potentiostat?
Good question. If you want to monitor the stability of your potential, you can switch it on and perform open circuit potential. The outcome will be a profile of your metal's potential over time.
Hi Mr. Mohd. Do I need to stirr while taking polarization measurements ?
Hi, it depends on your interest. If it is in static conditions then you dont have to stir but if it is in dynamic flow studies then you need to stir
@@mohdhazwan6523 thank you very much!
Is Potentidynamic Polarisation same as LPR?
not literally the same. PDP plots are logarithmic version of current density, while LPR plots are linear version of current density. The potential range between these two methods are not the same as well. PDP have slightly bigger range than LPR.
@@mohdhazwan6523 which reference can I refer to know the potential range between these two?
@@chuaalvin7455 well there is a lot of references available. For PDP the potential range is normally around +-300 mV or +-250 mV from Eocp, while for LPR the potential range is around +-20 mV only from Eocp.
Hi Mr Mohd, if I want to measure the corrosion rate for coating application using this method, do I need to apply coating on both side of the sample? Or 1 side is enough?
Hi Ahza, for this method one specific exposed area is enough. Corrosion rate use electrochemical technique can be calculated as follows:
CR (mpy) = (0.13 x icorr x Mew)/density
Where icorr must be in microamperes, Mew is the equivalent weight (atomic mass/valency) and density is the density of the studies metal
@@mohdhazwan6523 Thank you so much dr for your reply, really helpful. Much appreciated. Btw, are you familiar with the composite coating dr?
@@nurahzachenasir4299 yes, i am currently working on composite coatings (epoxy based reinforced filler)..let me know if you need any help
@Mohd Hazwan dr, do you know how to measure coating thickness? And what equipment do we usually use to measure the thickness?
@@nurahzachenasir4299 i use thickness gauge. But if you dont have it, you can calculate the thickness via cross sectional SEM
very nice
Thanks!
Hi Mohd, I would love to speak with you in order to better understand the different methods I could use to corrosion test my stainless steel. Would you be open to a zoom call? I’m in Orlando, Florida, so I would be on EST time
Hi Cameron, are you testing on SS316 or SS318?
can I send you some samples and you do the testing for it ?
yes can. but there will be some testing charges.
Hi i m new researcher n i m going to work on corrosion inhibition but can u please suggest me which electrochemical machine is very good for corrosion inhibition study
Oh well, all potentiostats have the same purpose. I have been working with different types of potentiostats and found that each potentiostats have its own uniqueness. To me, it doesn't matter which brand you are working with, the most important thing is the consistency and the ease of setting. That's all
Thanks Dr. Hazwan for the video, interesting one. I want to measure the corrosion rate of two metals (Titanium and Aluminium) in FeCl2/HCL/KCL solutions. Would you be able to help me to do the experimental set-up. That would be nice If I can have your email address, please.
Hi, is the two metals are separated one (galvanic cell) or it is an alloy (mixture of Al and Ti)?
Address... I want to test ss316l samples...
Hello, please check my details from chem.usm.my
hi can i check the corrosive effect of a pcm on aluminium sheet with this method
Yes of course you can
@@mohdhazwan6523 the pcm will be solid at room temperature the volume ia roughly 10 ml only
Dear John, you can dissolve the pcm first with small amount of ethanol and later dilute it with the electrolyte of interest (distilled water or brine or acid solution). Remember solubility is crucial for corrosion inhibition studies.
Can u please share the price now i want to buy this one
The potentiostat price is ranging around USD 19k to 40k. It depends on the specification that you need.
@@mohdhazwan6523 what about this gamry 600
@@gyaniyumnam7266 this is the old version. Most of Gamry 600 has been upgraded to Gamry Reference 600+. The price is almost the same as mentioned earlier
@@mohdhazwan6523 thnk u dear u help me alot
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