This video is very interesting and well executed: I was looking for some videos which shows practically what I am studying theorethically in the metallurgy course, and this is perfect to see how these techniques are applied in the real world :)
Congratulations your presentations are very good. I would ask you if you could put subtitles for people with hearing problems. Congratulations again and thanks for your effort.
+ΘΩΜΑΣ ΚΟΥΜΑΡΗΣ Answer to "I would ask you if you could put subtitles for people with hearing problems": Not at the moment, sorry, but a lot of thanks for this suggestion, we are thinking about it.
Thank you for posting this excellent video and also the Metallography Part 1, on macroscopic techniques. These were very informative and helpful for me.
@@robertmurrayscott9542 I am a music composer now I sell my music on Apple Music Spotify etc but I also do research on Mathematics and science in general the research part is a little less official than the music
Thanks for sharing thats interesting And very clean and fully furnished lab. Where is it? Do you Guys have a graduate program in metallography? My major is on microstructure mainly on steel. I really need to study more on this subject.
The lab is at Karlsruhe University of Applied Sciences in Southern Germany. Sorry to state, that we do not specialise in this area, it just part of our Mechanical Engineering education.
Hi, informative video, I have a question though: How to break a small sample out of a resin? if you have to perform hardness and you don't want the resin to effect the measurements, how shall I proceed to take out a sample from resin?
Answer to "How to break a small sample out of a resin? if you have to perform hardness and you don't want the resin to effect the measurements, how shall I proceed to take out a sample from resin?": You do not need to remove the sample from the resin. Select a suitable test force for the Vickers hardness test (e.g. 1 or 0.1 kp) and carry out the test. Only clamp the resin properly, it should not move horizontally or tilt. A slight elastic yielding has no consequences, as the Vickers test is force-controlled. Good luck!
At my university we do the grinding and polishing *without* the resine. The samples we have have a bigger diameter, but I'm still afraid that might be why we always get such bad results haha.
Answer to "Are you still running Windows 2000 for the microscope ;D" Might have been at that time, when we recorded the video; we have had some variants in the meantime, now Win7, we are very conservative ...
the eye piece of the telescope was removed from the theodolite so the observer could observe distance of even one meter ........ when the eye piece of the telescope has a higher resolution and rays incident on the lens can resolved into its constituent elements ....and distant objects will be able to visualize the grain structure of the metallography ........
For brass 3% Ferric Chloride works , aluminium is usually anodised in fluoroboric acid - and looked at under polarised light to see the grains - castings usually don't need etching because the Si in the alloys stands out in the polished state.
Answer to "How to etch 3D printed 316 l sample ? I am etching with swab I can scratches I think those are of swab. Is it okay to deep sample in etchant": It is generally better to prepare a good microsection and then immerse the entire microsection in the etchant, as shown in the video. Etching with a swab is also possible, but only soft and clean swabs should be used to avoid scratches.
I thought at first that the resin was cured in vacuum, because there is no air included. Where can I buy that kind of resin? It is different from the one used by modellers.
Answer to "I thought at first that the resin was cured in vacuum, because there is no air included. Where can I buy that kind of resin? It is different from the one used by modellers." There are many types of resins, such as two-component resins or heat curing resins. In the video we used a light-curing resin (Technovit 2000 LC), which has the advantage of transparency and easy understanding of our work in the video, but also some disadvantages. In most cases a vacuum is not required. But as you point out, vacuum curing is best. Often the filling-in of the resin (mostly not used with the light-curing ones) is done under vacuum, and then the mold is set under high pressure and elevated temperature to bring the resin to the smallest remaining cavities and start curing.
i would like to asking u about a decarburazion process.. i dont get the layer on the material after eching process.. can u post the proper step or method for decarburazation for quenching steel.. tq
Answer to "What is the appropriate method to etch the zirconia material": In general, ceramic materials such as zirconia (ZrO2) differ significantly from metallic materials. Unfortunately, we are not experts in ceramics. However, chemical etching with phosphoric acid or thermal etching are common.
First I want to say thank you, this is awesome I don't know if I ever would have got to see how any of this is done. One thing though... how can you go from "This is now called a metalagraphic specimen" expecting people to just go "ok, I understand", but then explain for a minute what inverted means? Not actually a critique just made me laugh.
The etching procedure has to be performed inside a fume hood. You shouldn't rinse the specimen with water and alcohol inside the sink after etching. It should be rinsed with alcohol and the waste should go into a labelled polyethylene container.
Answer to "The etching procedure has to be performed inside a fume hood. You shouldn't rinse the specimen with water and alcohol inside the sink after etching. It should be rinsed with alcohol and the waste should go into a labelled polyethylene container.": You are absolutely right, this is the correct procedure. But in our case, all chemicals (alcohol, diluted nitric acid, very small amounts, few samples) our procedure is allowed in a laboratory, at least in Germany. But only in this case! In other circumstances (vapours, hazardous chemicals, environmentally harmful chemicals) you have to take all the precautions you mentioned.
Answer to "It's a very instructive summary about cross section metalography, How can I know what materials are using? Can I buy those?": The materials have been collected over several years on many occasions, one cannot buy them, sorry.
Answer to "Excellent video! Which solution do you use to reveal the grains? Thanks." The etching agents may be quite different for different materials. The etching agent for the steel in the video was a solution of 10 % of concentrated HNO3 in 90 % of ethanol. It works quite well.
Answer to "Thanks for the answer. I'm trying to polish aluminum but it's very soft and I can not polish it all right." Aluminium materials, especially soft aluminium, need special preparation techniques. There are a number of books on the market who deal with this problem. You can also contact the websites of the typical suppliers of metallographic preparation materials. Sorry, I do not have enough own experience for a good advice.
Answer to "What standard does he talk about when he says C80?": C80 is a European standard designation and refers to an unalloyed steel with 0.8% carbon content.
Answer to "What the advantage from rinsing the sample with alcohol": Normal tap water would cause staining on the sample surface. Distilled water is better in this respect, but tends to coagulate on the sample surface or even corrode it during the drying process. Alcohol (ethanol) is a good rinsing and cleaning agent in most cases. It does not coagulate on the surface when drying, it is not corrosive (in most cases), and does not cause environmental damage.
Ahmed El Fadel The liquid is just water. Sometimes we use water with a small addition of a detergent or a small addition of an organic acid to remove rust or oxides.
Dear sir i have an doupt here this type, lesin was used on plastic mould purpose and treated but then why we use backelite powder on mould in the ECD findout.
Answer to: "Best clean with ultrasonic between polishing form 6 to 1 microns and to 0.1 alumina" Yes, ultrasonic cleaning is a good option, and we use it a lot. However, it is not always necessary, and it has to be done cautiously. Some materials may be damaged when using ultrasonic cleaning with too much intensity and for a too long time.
If I want to assess the structure of cement concrete, I will have to dehydrate the samples, which indicates that I am going to visualize the structure without the important hydration products such as CSH (calcium silicate hydrate) and CH (calcium hydroxide). Don't you think it does not portray a good message in the field of concrete or cement? (Nevertheless, if you search about SEM of cement- or concrete-based samples, you will come across a myriad of papers incorporating SEM testing of these products.)
Answer to "If I want to assess the structure of cement concrete, I will have to dehydrate the samples, ...": For a more detailed answer see also our SEM video comments. In metallography (or rather materialography) the problem is similar. However, here there is not the problem with the vacuum. Here it is a matter of embedding the sample appropriately and replacing all liquids with suitable solids, for example polymers, without changing the sample. A standard method in biology, simplified: replace the water with alcohol, replace the alcohol with liquid resin, cure the resin, and then prepare your microsection.
Answer to "please advise what program or image analyzer you use to see the actual image on the monitor":It is the Axiovision programme from Zeiss. There are many other programs on the market that serve the purpose in a similar manner ...
Answer to "Can we conduct the examination of microscope without etching process? can someone explain for me?": Without etching (only grinding and polishing), you can only see the phases in the material that have a different color or light absorption in comparison with the surrounding phases, but you cannot see grain boundaries, for example. This is shown in the video.
Answer to "if I only have a 160x magnification microscope ...can I use it for microstructure analysis": Well, to use different magnifications is always better, but you can already do a lot with 160x, it is a good compromise. Just try it!
Answer to "In the final etching test he is not wear hand gloves..": Correct, but in this case that is due to the comparatively quite mild etchant. We did this because we have a lot of experience with this etchant. But please remember to wear gloves in any case!
Answer to "May I ask what etchant is suitable for the 304 stainless steel? I fail in observing the microstructure." In this case you have to use very strong etching agents, for example a mixture of HCl, water, HNO3, and other substances, too complicated to tell here. You find it in the internet and in some books on metallography - and very important, you also find the appropriate safety instructions.
Answer to "Em, can someone tell me what is the liquid used in the final process of polishing?" The diamond suspension polishing was done with 6 micrometers resp. 3 micrometers grain size diamonds in a liquid that mainly consists of water (we do not know the exact composition, a lubricant is added). The last polishing operation was done with alumina suspension (50 nm grain size) in water.
Answer to "Why pearlite appears as dark and ferrite appears as white?": The etching method we have used is grain boundary and phase boundary etching. This etching method does not produce any colours and there is no black and white contrast. So after etching, the surface of the sample is still completely clean, metallic and shiny. The only effect created by etching is a 3D structuring of the surface: small grooves are created between grains and between different phases. Ferrite consists of one phase (ferrite itself), pearlite consists of small lamellae of two phases (ferrite and cementite). Although ferrite and cementite are silvery and shiny, the phase boundaries between them have a three-dimensional structure. Thus, a ferrite grain appears light, while a pearlite region appears rather dark, because this etching process has created many small grooves between the ferrite and cementite crystals. It is difficult to explain this without a very long explanation and the iron-carbon phase diagram.
Answer to the question "Why was a fine grinding step not necessary?": All grinding steps are (normally) necessary, including the fine grinding step. The fine grinding step was not shown in the video, but only mentioned in the off-text.
Answer to "Plz tell the precise time of etching": The etching time can vary greatly, from 2 seconds to several minutes, depending on the etchant and the material. In most cases, you have to try it out.
Absolutely not. Cloths can only go rougher, once used with higher grain size (lower grit), it can only go for that size, no longer it can't be used for lower grain size (higher grit). Since there is no way to keep samples absolutely clean form the previous stage, service time of fine cloths (>1 micron) is very short. But they can be then used for 3 microns, then for 6 microns, etc. Fairly serviced fine cloths can also be used as intermediate step to clean up the sample before introducing it to a serviceable fine cloth of the same polishing step.
This is really great. I'm starting my titanium sample prep in due course. I am wondering whether there is a difference in results between automatic polishing/grinding and manual polishing/grinding.
Answer to "I am wondering whether there is a difference in results between automatic polishing/grinding and manual polishing/grinding": Properly carried out, there should not be a difference. Generally, titanium samples are comparatively difficult to prepare.
I was recommended this video by my teacher, totally worth the time.
هلو ممكن طلب
Thanks so much for making your videos available! They are great!
How many of you are here because of lab of material science !!
I don’t know why in here. But I like it here
Lo spero anche io un giorno
Me
I'm here because i have to go and perform some experiments for my project work, and it's due tomorrow.
This video is very interesting and well executed: I was looking for some videos which shows practically what I am studying theorethically in the metallurgy course, and this is perfect to see how these techniques are applied in the real world :)
Nice presentation and explanation. Glove up when using chemicals as a caution.
Good suggestion
what is the chemical used?
very nice video, very educating
By watching this video i have been able to check the grain size of metals. the thorough explanation helped me a lot.
Keep on doing it....It's very useful for me...Thanks for the team...
Congratulations your presentations are very good. I would ask you if you could put subtitles for people with hearing problems. Congratulations again and thanks for your effort.
+ΘΩΜΑΣ ΚΟΥΜΑΡΗΣ Answer to "I would ask you if you could put subtitles for people with hearing problems": Not at the moment, sorry, but a lot of thanks for this suggestion, we are thinking about it.
This channel is epic, biblical, mind-blowing. You guys are the best. Thanks for the absolulety HIGH QUALITY CONTENT. Aaaaaa
2019 and still impacting students like me. thanks.
Any video on colour or tint etching will be highly appreciable
Great video! I would've liked to see some PPE.
Thank you very much for share this video it is really very help for sample preparing
Awesome video… thanks for sharing this. So detailed and puts you in shoes of the lab person.
I like dryer setup. What's more scientific than ordinary hairdryer attached to the holder.
best video on material science. more videos on material science and NDT , DESTRUCTIVETESTING will be appreciated.
Thank you! That's so precise.
Thank you for posting this excellent video and also the Metallography Part 1, on macroscopic techniques. These were very informative and helpful for me.
I did all these in the university while studying mining and metallurgical engineering
where do you work now?
@@robertmurrayscott9542 I am a music composer now I sell my music on Apple Music Spotify etc but I also do research on Mathematics and science in general the research part is a little less official than the music
thank you i can now write my practical paper
Thanks for sharing thats interesting And very clean and fully furnished lab.
Where is it?
Do you Guys have a graduate program in metallography?
My major is on microstructure mainly on steel.
I really need to study more on this subject.
The lab is at Karlsruhe University of Applied Sciences in Southern Germany. Sorry to state, that we do not specialise in this area, it just part of our Mechanical Engineering education.
Thanks for your response
This is a very good explanation
Hi, informative video, I have a question though:
How to break a small sample out of a resin? if you have to perform hardness and you don't want the resin to effect the measurements, how shall I proceed to take out a sample from resin?
Answer to "How to break a small sample out of a resin? if you have to perform hardness and you don't want the resin to effect the measurements, how shall I proceed to take out a sample from resin?": You do not need to remove the sample from the resin. Select a suitable test force for the Vickers hardness test (e.g. 1 or 0.1 kp) and carry out the test. Only clamp the resin properly, it should not move horizontally or tilt. A slight elastic yielding has no consequences, as the Vickers test is force-controlled. Good luck!
Thanks it helped me on my report.
Nice presentation and explanation
Thank you
Excellent!
Very education science video🔬thank you sir
pozdravljen sotrpin, student strojne fakultete ljubljana
Thank you for this great video
It's a very nice video, thanks for sharing...Nice job
Had this lab today except the resin capsule was a quarter of the size and was not fun to grind.
At my university we do the grinding and polishing *without* the resine. The samples we have have a bigger diameter, but I'm still afraid that might be why we always get such bad results haha.
Superb demonstration👌🏼👌🏼👌🏼
Excellent video
Where is the PPE?
I have understood
Good information...love from mandya ❤️❤️
It has the crux of my 4 year Btech course on Metallurgy
Very useful for my work as a knife maker 👍🏻
Thanks a lot...
دەست خۆش
9:24 "Excitement increases"
Cool video. I didn't know robots are running this lab :)
Are you still running Windows 2000 for the microscope ;D
Answer to "Are you still running Windows 2000 for the microscope ;D" Might have been at that time, when we recorded the video; we have had some variants in the meantime, now Win7, we are very conservative ...
the eye piece of the telescope was removed from the theodolite so the observer could observe distance of even one meter ........ when the eye piece of the telescope has a higher resolution and rays incident on the lens can resolved into its constituent elements ....and distant objects will be able to visualize the grain structure of the metallography ........
Thank for providing information
Very instructive. Thanks for sharing :)
What are the best etchant for brass and Aluminum?
For brass 3% Ferric Chloride works , aluminium is usually anodised in fluoroboric acid - and looked at under polarised light to see the grains - castings usually don't need etching because the Si in the alloys stands out in the polished state.
Superb video sir. Thank you very much...
How to etch 3D printed 316 l sample ? I am etching with swab I can scratches I think those are of swab. Is it okay to deep sample in etchant
Answer to "How to etch 3D printed 316 l sample ? I am etching with swab I can scratches I think those are of swab. Is it okay to deep sample in etchant": It is generally better to prepare a good microsection and then immerse the entire microsection in the etchant, as shown in the video. Etching with a swab is also possible, but only soft and clean swabs should be used to avoid scratches.
Is this recommended for Marine Engineers
Great video!
I thought at first that the resin was cured in vacuum, because there is no air included. Where can I buy that kind of resin? It is different from the one used by modellers.
Answer to "I thought at first that the resin was cured in vacuum, because there is no air included. Where can I buy that kind of resin? It is different from the one used by modellers." There are many types of resins, such as two-component resins or heat curing resins. In the video we used a light-curing resin (Technovit 2000 LC), which has the advantage of transparency and easy understanding of our work in the video, but also some disadvantages. In most cases a vacuum is not required. But as you point out, vacuum curing is best. Often the filling-in of the resin (mostly not used with the light-curing ones) is done under vacuum, and then the mold is set under high pressure and elevated temperature to bring the resin to the smallest remaining cavities and start curing.
hello mecheng 2021
It was helpful and interesting keep making videos they are great
hi sir... may i ask u 1 question.. how to get good sample cross section for pcb...
I would like a report on this experience in Word format
What do you mean by chemical etching? what kind of solvent do you use?
amazing video.........and also i need information about rock sampling steps for poly sections,,, thank you for great video.....
superb video sir
i would like to asking u about a decarburazion process.. i dont get the layer on the material after eching process.. can u post the proper step or method for decarburazation for quenching steel.. tq
What is the appropriate method to etch the zirconia material
Answer to "What is the appropriate method to etch the zirconia material": In general, ceramic materials such as zirconia (ZrO2) differ significantly from metallic materials. Unfortunately, we are not experts in ceramics. However, chemical etching with phosphoric acid or thermal etching are common.
The specimen faces downwards. This has the advantage of the specimen facing downwards. Proceeds to zoom in on downwards facing specimen.
Thanks, that's informative
First I want to say thank you, this is awesome I don't know if I ever would have got to see how any of this is done.
One thing though... how can you go from "This is now called a metalagraphic specimen" expecting people to just go "ok, I understand", but then explain for a minute what inverted means? Not actually a critique just made me laugh.
هلو ممكن طلب
Some new videos regarding different techniques in metallurgy must be recorded. Please.
Well explained
The etching procedure has to be performed inside a fume hood. You shouldn't rinse the specimen with water and alcohol inside the sink after etching. It should be rinsed with alcohol and the waste should go into a labelled polyethylene container.
Answer to "The etching procedure has to be performed inside a fume hood. You shouldn't rinse the specimen with water and alcohol inside the sink after etching. It should be rinsed with alcohol and the waste should go into a labelled polyethylene container.": You are absolutely right, this is the correct procedure. But in our case, all chemicals (alcohol, diluted nitric acid, very small amounts, few samples) our procedure is allowed in a laboratory, at least in Germany. But only in this case! In other circumstances (vapours, hazardous chemicals, environmentally harmful chemicals) you have to take all the precautions you mentioned.
Very informative 👌😊
It's a very instructive summary about cross section metalography, How can I know what materials are using? Can I buy those?
Answer to "It's a very instructive summary about cross section metalography, How can I know what materials are using? Can I buy those?": The materials have been collected over several years on many occasions, one cannot buy them, sorry.
Excellent video! Which solution do you use to reveal the grains? Thanks.
Answer to "Excellent video! Which solution do you use to reveal the grains? Thanks." The etching agents may be quite different for different materials. The etching agent for the steel in the video was a solution of 10 % of concentrated HNO3 in 90 % of ethanol. It works quite well.
@@MaterialsScience2000 Thanks for the answer. I'm trying to polish aluminum but it's very soft and I can not polish it all right.
Answer to "Thanks for the answer. I'm trying to polish aluminum but it's very soft and I can not polish it all right." Aluminium materials, especially soft aluminium, need special preparation techniques. There are a number of books on the market who deal with this problem. You can also contact the websites of the typical suppliers of metallographic preparation materials. Sorry, I do not have enough own experience for a good advice.
Whay standard does he talk about when he says C80?
Answer to "What standard does he talk about when he says C80?": C80 is a European standard designation and refers to an unalloyed steel with 0.8% carbon content.
@@MaterialsScience2000 thank you for you reply really help full
Hi Tai, hom nay moi ranh ghe tham Tai ne, chuc kenh T ngay canh ohat trien nhe
very nice!
What the advantage from rinsing the sample with alcohol
Answer to "What the advantage from rinsing the sample with alcohol": Normal tap water would cause staining on the sample surface. Distilled water is better in this respect, but tends to coagulate on the sample surface or even corrode it during the drying process. Alcohol (ethanol) is a good rinsing and cleaning agent in most cases. It does not coagulate on the surface when drying, it is not corrosive (in most cases), and does not cause environmental damage.
Great video! Very informational, and clear to the point. What was the liquid in the ultra sonic cleaner? Was that just water?
Ahmed El Fadel The liquid is just water. Sometimes we use water with a small addition of a detergent or a small addition of an organic acid to remove rust or oxides.
Dear sir
i have an doupt here this type, lesin was used on plastic mould purpose and treated but then why we use backelite powder on mould in the ECD findout.
resin(lesin)
just want to ask have you ever prepared thin section ung diamond paste, uncover thin section of rock specimen? thanks in advance
Best clean with ultrasonic between polishing form 6 to 1 microns and to 0.1 alumina
Answer to: "Best clean with ultrasonic between polishing form 6 to 1 microns and to 0.1 alumina" Yes, ultrasonic cleaning is a good option, and we use it a lot. However, it is not always necessary, and it has to be done cautiously. Some materials may be damaged when using ultrasonic cleaning with too much intensity and for a too long time.
If I want to assess the structure of cement concrete, I will have to dehydrate the samples, which indicates that I am going to visualize the structure without the important hydration products such as CSH (calcium silicate hydrate) and CH (calcium hydroxide). Don't you think it does not portray a good message in the field of concrete or cement? (Nevertheless, if you search about SEM of cement- or concrete-based samples, you will come across a myriad of papers incorporating SEM testing of these products.)
Answer to "If I want to assess the structure of cement concrete, I will have to dehydrate the samples, ...": For a more detailed answer see also our SEM video comments. In metallography (or rather materialography) the problem is similar. However, here there is not the problem with the vacuum. Here it is a matter of embedding the sample appropriately and replacing all liquids with suitable solids, for example polymers, without changing the sample. A standard method in biology, simplified: replace the water with alcohol, replace the alcohol with liquid resin, cure the resin, and then prepare your microsection.
please advise what program or image analyzer you use to see the actual image on the monitor
Answer to "please advise what program or image analyzer you use to see the actual image on the monitor":It is the Axiovision programme from Zeiss. There are many other programs on the market that serve the purpose in a similar manner ...
Can we conduct the examination of microscope without etching process? can someone explain for me?
Answer to "Can we conduct the examination of microscope without etching process? can someone explain for me?": Without etching (only grinding and polishing), you can only see the phases in the material that have a different color or light absorption in comparison with the surrounding phases, but you cannot see grain boundaries, for example. This is shown in the video.
So clear
best video
if I only have a 160x magnification microscope ...can I use it for microsrtucture analysis
Answer to "if I only have a 160x magnification microscope ...can I use it for microstructure analysis": Well, to use different magnifications is always better, but you can already do a lot with 160x, it is a good compromise. Just try it!
In the final etching test he is not wear hand gloves..
Answer to "In the final etching test he is not wear hand gloves..": Correct, but in this case that is due to the comparatively quite mild etchant. We did this because we have a lot of experience with this etchant. But please remember to wear gloves in any case!
May I ask what etchant is suitable for the 304 stainless steel? I fail in observing the microstructure.
Answer to "May I ask what etchant is suitable for the 304 stainless steel? I fail in observing the microstructure." In this case you have to use very strong etching agents, for example a mixture of HCl, water, HNO3, and other substances, too complicated to tell here. You find it in the internet and in some books on metallography - and very important, you also find the appropriate safety instructions.
@@MaterialsScience2000 thx
Em, can someone tell me what is the liquid used in the final process of polishing?
Answer to "Em, can someone tell me what is the liquid used in the final process of polishing?" The diamond suspension polishing was done with 6 micrometers resp. 3 micrometers grain size diamonds in a liquid that mainly consists of water (we do not know the exact composition, a lubricant is added). The last polishing operation was done with alumina suspension (50 nm grain size) in water.
nice
Rodriguez Linda Davis Brian Martin Kimberly
thanks
i found same viedo in german language, but lucky to have in englisch also .Thanks
Great video
Can't believe you used comic sans
Why pearlite appears as dark and ferrite appears as white?
Answer to "Why pearlite appears as dark and ferrite appears as white?": The etching method we have used is grain boundary and phase boundary etching. This etching method does not produce any colours and there is no black and white contrast. So after etching, the surface of the sample is still completely clean, metallic and shiny. The only effect created by etching is a 3D structuring of the surface: small grooves are created between grains and between different phases. Ferrite consists of one phase (ferrite itself), pearlite consists of small lamellae of two phases (ferrite and cementite). Although ferrite and cementite are silvery and shiny, the phase boundaries between them have a three-dimensional structure. Thus, a ferrite grain appears light, while a pearlite region appears rather dark, because this etching process has created many small grooves between the ferrite and cementite crystals. It is difficult to explain this without a very long explanation and the iron-carbon phase diagram.
Why was a fine grinding step not necessary?
Answer to the question "Why was a fine grinding step not necessary?": All grinding steps are (normally) necessary, including the fine grinding step. The fine grinding step was not shown in the video, but only mentioned in the off-text.
How do you de-mount for SEM analysis?
Plz tell the precise time of etching
Answer to "Plz tell the precise time of etching": The etching time can vary greatly, from 2 seconds to several minutes, depending on the etchant and the material. In most cases, you have to try it out.
am currently working on CoCr alloy (Co-65%, Cr-30, Mo-5%) and still trying out a suitable etchant. Can you please suggest any etchant for that?
Have you already tried "aqua regia"?
+Carmo Pelliciari funny enough i just thought of trying that today. thanks
I´ve used aqua regia for etching both cast and wrought CoCrMo alloys and it worked fine.
Sir send details of procedure.SOP
can we use the same polishing cloth for all the different polishing stages?
Absolutely not. Cloths can only go rougher, once used with higher grain size (lower grit), it can only go for that size, no longer it can't be used for lower grain size (higher grit). Since there is no way to keep samples absolutely clean form the previous stage, service time of fine cloths (>1 micron) is very short. But they can be then used for 3 microns, then for 6 microns, etc. Fairly serviced fine cloths can also be used as intermediate step to clean up the sample before introducing it to a serviceable fine cloth of the same polishing step.
@@Duke7562 so it means that after polishing with 6 microns, I would need to use a new polishing cloth to continue with the 3 microns?
@@mcmc727 Yes. You need as many cloths as polishing steps, each one for each step, never to be mixed around.
🙏🙏
Which university??
This is really great. I'm starting my titanium sample prep in due course. I am wondering whether there is a difference in results between automatic polishing/grinding and manual polishing/grinding.
Answer to "I am wondering whether there is a difference in results between automatic polishing/grinding and manual polishing/grinding": Properly carried out, there should not be a difference. Generally, titanium samples are comparatively difficult to prepare.