Metallography Part II - Microscopic Techniques

Metallography Part II - Microscopic Techniques
- Sectioning of a sample
- Wet grinding in several stages
- Polishing in several stages
- Etching
- Observation with a metallographic microscope
Responsible for this video: Prof. Dr.-Ing. Rainer Schwab, Hochschule Karlsruhe, University of Applied Sciences, Karlsruhe, Germany

[@WeldNotes]

Thanks so much for making your videos available! They are great!

[@FactsReelAll]

How many of you are here because of lab of material science !!

[@Marfolls]

I don’t know why in here. But I like it here

[@supergreatgirl4522]

Lo spero anche io un giorno

[@lakshmitondur8245]

Me

[@1080pMarco]

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 :)

[@muhammadahmad9627]

By watching this video i have been able to check the grain size of metals. the thorough explanation helped me a lot.

[@parimisreekar]

Awesome video… thanks for sharing this. So detailed and puts you in shoes of the lab person.

[@citizencitizen3040]

Keep on doing it....It's very useful for me...Thanks for the team...

[@jaypanchal654]

very nice video, very educating

[@fatimazaghab4262]

Thank you! That's so precise.

[@johndilsaver8409]

Thank you for posting this excellent video and also the Metallography Part 1, on macroscopic techniques. These were very informative and helpful for me.

[@infantberwin8842]

Superb demonstration👌🏼👌🏼👌🏼

[@KanenOmer]

It's a very nice video, thanks for sharing...Nice job

[@Felipe-53]

This channel is epic, biblical, mind-blowing. You guys are the best. Thanks for the absolulety HIGH QUALITY CONTENT. Aaaaaa

[@Felipe-53]

2019 and still impacting students like me. thanks.

[@michellep4219]

Great video! I would've liked to see some PPE.

[@ahsanhaider5070]

Thank you very much for share this video it is really very help for sample preparing

[@AniketTurkel]

I was recommended this video by my teacher, totally worth the time.

[@user-mo4lg1zr7d]

هلو ممكن طلب

[@zeus-zh8tk]

Thank you for this great video

[@sourabhgujar2478]

It was helpful and interesting keep making videos they are great

[@lincolngovender2137]

Excellent!

[@Mechanical114]

Nice presentation and explanation

[@ibrahimshareef4743]

best video on material science. more videos on material science and NDT , DESTRUCTIVETESTING will be appreciated.

[@ganeshgs2241]

Superb video sir. Thank you very much...

[@samanqurbany5241]

amazing video.........and also i need information about rock sampling steps for poly sections,,, thank you for great video.....

[@karnatakatrainz2493]

Good information...love from mandya ❤️❤️

[@calmdown1992]

Great video!

[@tcurtis4360]

Nice presentation and explanation. Glove up when using chemicals as a caution.

[@karthiklakshmi]

Good suggestion

[@dineshvyas]

Excellent video

[@kknives_switzerland]

Very useful for my work as a knife maker 👍🏻

[@immanuvelkodaikanal4950]

What do you mean by chemical etching? what kind of solvent do you use?

[@wildliferescuersofkhed5041]

Very informative 👌😊

[@muhammadnaumannoor815]

This is a very good explanation

[@user-yo5hb3yp3x]

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.

[@MaterialsScience2000]

+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.

[@futuremaybe5934]

thank you i can now write my practical paper

[@ibrahimnazemqader9153]

Thanks a lot... دەست خۆش

[@nidhishah7786]

superb video sir

[@akashdileepgandhi7363]

Any video on colour or tint etching will be highly appreciable

[@arumugam8254]

Very education science video🔬thank you sir

[@POSSIBLEEDITOR]

Thank for providing information

[@grishmabaratam9624]

Thanks, that's informative

[@choolit_TV]

just want to ask have you ever prepared thin section ung diamond paste, uncover thin section of rock specimen? thanks in advance

[@subhradeeppaul2869]

It has the crux of my 4 year Btech course on Metallurgy

[@tetelominda1480]

Thanks it helped me on my report.

[@nemod3338]

I like dryer setup. What's more scientific than ordinary hairdryer attached to the holder.

[@norhidayahadeq2107]

hi sir... may i ask u 1 question.. how to get good sample cross section for pcb...

[@uwofracture]

Very instructive. Thanks for sharing :) What are the best etchant for brass and Aluminum?

[@JohnPilling25]

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.

[@sufriekazara]

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

[@pritom7298]

best video

[@DAVIDJOHNSON-te6jc]

Well explained

[@TheDrB0B]

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.

[@youkivu704]

Hi Tai, hom nay moi ranh ghe tham Tai ne, chuc kenh T ngay canh ohat trien nhe

[@lukas.v.4320]

pozdravljen sotrpin, student strojne fakultete ljubljana

[@Mugenremix]

Great video! Very informational, and clear to the point. What was the liquid in the ultra sonic cleaner? Was that just water?

[@MaterialsScience2000]

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.

[@Victorator1985]

Excellent video! Which solution do you use to reveal the grains? Thanks.

[@MaterialsScience2000]

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.

[@Victorator1985]

@@MaterialsScience2000 Thanks for the answer. I'm trying to polish aluminum but it's very soft and I can not polish it all right.

[@MaterialsScience2000]

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.

[@williamhinrichs6558]

Great video Can't believe you used comic sans

[@user-ud5jh1eb6z]

What is the appropriate method to etch the zirconia material

[@MaterialsScience2000]

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.

[@batobalani4787]

very nice!

[@charissanoria1892]

please advise what program or image analyzer you use to see the actual image on the monitor

[@MaterialsScience2000]

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 ...

[@Gamster420]

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.

[@MaterialsScience2000]

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.

[@keivansamani3437]

How do you de-mount for SEM analysis?

[@zomisintu]

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.

[@MaterialsScience2000]

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.

[@zomisintu]

Thanks for your response

[@chris_louis]

Thank you

[@Engineer_MayDay]

Is this recommended for Marine Engineers

[@achirabdirzak8010]

Veeeryyyy nicee thank yoo

[@footstoptravel2128]

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?

[@MaterialsScience2000]

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!

[@keongfuimay4552]

May I ask what etchant is suitable for the 304 stainless steel? I fail in observing the microstructure.

[@MaterialsScience2000]

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.

[@keongfuimay4552]

@@MaterialsScience2000 thx

[@Waitwhat469]

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.

[@user-mo4lg1zr7d]

هلو ممكن طلب

[@kokomanation]

I did all these in the university while studying mining and metallurgical engineering

[@robertmurrayscott9542]

where do you work now?

[@kokomanation]

@@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

[@Vvsssathiya]

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.

[@MaterialsScience2000]

Answer to " 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." There are many different types od embedding materials available, each of them having specific pros and cons. The main advantage of light curing resin is the transparency, so the position of the microsection within the specimen is easily observable. Main disadvantages are the low hardness of the resin and high shrinkage during curing (sometimes leading to gaps between the specimen and the resin).

[@ramzinasereddin8840]

So clear

[@user-ud5jh1eb6z]

What the advantage from rinsing the sample with alcohol

[@MaterialsScience2000]

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.

[@MuhammadTayyab-rr1qb]

Some new videos regarding different techniques in metallurgy must be recorded. Please.

[@movax20h]

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

[@MaterialsScience2000]

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 ...

[@edgarcamachomolinares9679]

It's a very instructive summary about cross section metalography, How can I know what materials are using? Can I buy those?

[@MaterialsScience2000]

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.

[@youssefm22]

what solution do you recommend for etching stainless?

[@MaterialsScience2000]

There are quite a few etchants available for stainless steels. For austenitic steels for instance we often use a solution of HCl, HNO3 and a special pickling inhibitor (Sparbeize in German) in water. For colour etching the Beraha II etching technique leads to good results.

[@thedamsam]

thanks

[@alternatedge8872]

Had this lab today except the resin capsule was a quarter of the size and was not fun to grind.

[@kaysseibrahim6477]

if I only have a 160x magnification microscope ...can I use it for microsrtucture analysis

[@MaterialsScience2000]

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!

[@boatengtwumdonkor5490]

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?

[@carmopelliciari9621]

Have you already tried "aqua regia"?

[@boatengtwumdonkor5490]

+Carmo Pelliciari funny enough i just thought of trying that today. thanks

[@carmopelliciari9621]

I´ve used aqua regia for etching both cast and wrought CoCrMo alloys and it worked fine.

[@edwardvojcak7429]

Best clean with ultrasonic between polishing form 6 to 1 microns and to 0.1 alumina

[@MaterialsScience2000]

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.

[@nealcharmkansel6150]

Em, can someone tell me what is the liquid used in the final process of polishing?

[@MaterialsScience2000]

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.

[@user-tc8bh5ii2e]

I would like a report on this experience in Word format

[@yashwantpatil2751]

which resin used for mounting of specimen

[@MaterialsScience2000]

+Yashwant Patil Answer to "which resin used for mounting of specimen?" We use Technovit 2000 LC, a light curing resin which has certain advantages (easy to handle, transparency > good for the control of the sectional plane) and certain disadvantages (relatively soft, high shrinkage, danger of gaps between specimen and resin).

[@georgen9755]

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 ........

[@gaurangpatel4015]

i found same viedo in german language, but lucky to have in englisch also .Thanks

[@mcmc727]

can we use the same polishing cloth for all the different polishing stages?

[@Duke7562]

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.

[@mcmc727]

@@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?

[@Duke7562]

@@mcmc727 Yes. You need as many cloths as polishing steps, each one for each step, never to be mixed around.

[@LonleyGuns]

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.

[@MaterialsScience2000]

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.

[@nathanielpoulter603]

The specimen faces downwards. This has the advantage of the specimen facing downwards. Proceeds to zoom in on downwards facing specimen.

[@nguyenngocvinhxd]

what is the acid solution used in this exam?

[@laszlovondracsek]

There are a lot of REAGENTS! For Fe-C alloys NITAL 2% is recommended.

[@Crazyzone1802]

Nice

[@suhaspatil16]

Is the polishing method same for concrete sample?

[@MaterialsScience2000]

Answer to "Is the polishing method same for concrete sample?": No, each material needs a special polishing method. Since I am not familiar with the preparation of concrete samples, I am afraid I cannot tell the proper method.

[@suhaspatil16]

@@MaterialsScience2000 Thank you.

[@ferdicanerbayram2447]

First of all, thanks for this nice video but I actually do not understand what are you saying between 5.40 and 5.50 in the video. A subtitle would be nice :)

[@ThePozzitron]

lab'a buradan çalıştım eyw

[@jansenpapworth9718]

hello mecheng 2021

[@SENPURSHOTTAM623]

Sir send details of procedure.SOP

[@syafinazmajuar1993]

Can we conduct the examination of microscope without etching process? can someone explain for me?

[@MaterialsScience2000]

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.

[@andrescreator7346]

could you add subtitles please?

[@nooryaseen9388]

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.)

[@MaterialsScience2000]

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.

[@amansharma4930]

🙏🙏

[@omaral-gallab7735]

Which university??

[@surajmg777]

Whay standard does he talk about when he says C80?

[@MaterialsScience2000]

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.

[@surajmg777]

@@MaterialsScience2000 thank you for you reply really help full

[@thetommy_]

nice