Transmission electron microscopy- sample preparation facility - I
It is used for precision thinning of samples (at final stages) to electron transparency for imaging with transmission electron microscope (TEM).
Make and Model
GATAN Inc. USA, Model 691
Available mode for use
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Planar samples and cross sectional samples under dual mode.
Specifications/Features
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Precision ion polishing system used topolish/thin down the samples to 80-100nm thin regions for TEM imaging
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It used to do polishing of most kinds of samples e.g. metallic, semiconductors and composites etc for TEM with energy 5keV and 40-50μA current under dual mode
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It can do polishing of heat sensitive samples under chill conditions with the use of liquid nitrogen.
Application
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The facility is used to make thin samples, which are electron transparent when viewed with a transmission electron microscope. The facility houses equipments that can make planar, as well as cross-sectional TEM samples from most materials types.
Facility in-charge
Contact Email
temsampleprep[at] iitb[dot] ac[dot] inContact no.
02221593613Location
G 025, Ground Floor, Department of Metallurgical Engineering & Material Science, IIT Bombay, Powai, Mumbai – 400076
Other contact person(s)
- Ms. Priyanka Kathar
Registration Link:
Information-External users
TEM Sample Preparation Central Facility.pdf116.39 KBRegistration form-External users
ExternalUsersRegistrationForm_TEMsamplepreprequisitionform.pdf33.87 KBVariable low speed Diamond saw :
Materials (ceramics and metals) can be reduced to 0.5mm in thickness using this technique, which uses a diamond blade, with the wheel speed varying between 100 to 400 rpm.
Tuned Piezo Cutting Tool :
This is used for cutting the material (both ceramic and metal) in the desired size and shape, so that it can be placed inside the TEM sample holder.
Ratings and Specifications :
- Disc Cutter External PSU (Power Supply Unit)
- Input Voltage = 100- 240 VAC (~)
- Output Voltage = 24VDC
- Output Power = 30W
- Frequency = 47-63 Hz
- Mains supply voltage fluctuations are not to exceed 10% of the nominal supply voltage
- Disc Cutter Power Jack ("DC in")
- DC Input Voltage = 24 VDC
- DC Input Current = 1.25 A
- Stereo Microscope Power Jack ("DC Out") used to power optional microscope
- Output Voltage = 24 VDC
- Output Current = 0.4A
- Environmental Conditions
- Non-operating relative humidity (non- condensing): 10-90%
- Storage temperature range 0- 65oC
- Operating Humidity Range: 20-80%
- Operating maximum thermal gradient: 15oC/hr
- Operating temperature range: 16-24oC
- (Information partly obtained from GATAN Manual)
Disc Punch :
(Used only for metallic sheets) The Disc punch prepares specimen discs of 3 mm in diameter and material thicknesses ranging from 10 μm to above 100 µm.
Specimen mounting hot plate :
This is used for firmly attaching specimen discs to stubs during grinding. This is done by using a low melting point wax polymer, heated on the hot plate, to form a strong, thin, hard adhesive bond. Operating temperature range is up to 130oCC.
Disc grinder:
This is used for holding the stub with the specimen attached for grinding down to a certain thickness. The GATAN Model 623 Disc Grinder possesses superior resolution and preloading of the specimen drive screw to result in excellent control of specimen thickness. By using weight of the grinder it limit the maximum polishing pressure the operator is able to reduce specimen damage to a minimum. The samples are polished using different grit silicon carbide papers such as 40 µm,15 µm and 5 µm, in sequence.
(Information partly obtained from GATAN Manual)
Dimple grinder :
After manual grinding, using disc grinder, precision thinning near the central region of the 3 mm disc specimen (or forming a dimple) is performed using dimple grinder.
The specifications are as follows:
| External PSU | Input Voltage = 100- 240 VAC (~) |
| Output Voltage = 24 VDC | |
| Output Power = 30W | |
| Frequency = 47-63 Hz | |
| Power Jack("DC in") | DC Input Voltage = 24 VDC |
| DC Input Current = 1.25A | |
| Stereo Microscope Powder Jack ("DC out") | Output Voltage 24 VDC Output Current= 0.4A |
- Environmental conditions
- Non –operating relative humidity: 10-90 %
- Storage temperature range: 0-65oC
- Operating humidity range: 20-80%
- Operating maximum thermal gradient: 15oC/hr
- Operating temperature range: 16-24oC
Precision Ion Polishing System (PIPS) :
After dimple grinding, the final stage precision polishing (thinning) of the 'dimpled' region up to electron transparency is done with the PIPS.
The specifications are as follows:
- Input Voltage = 100/120/240V
- Input Current = 3/3/1.5A
- Frequency = 50/60Hz
- Output Voltage = 120VAC 50/60Hz
- Output current = 3.0 A Max.
- Non-operating relative humidity (non - condensing): 10-90%
- Storage temperature range: 0- 65oC
- Operating humidity range: 20-80%
- Operating maximum thermal gradient: 15oC/hr
- Operating temperature range: 5-35oC
- For indoor use only
(Information partly obtained from GATAN Manual)
The facility for preparation of TEM samples, following the more conventional route, consists of a number of equipments (see below) under one roof, which needs to be used in a proper sequence. Also, TEM sample preparation necessitates manual skills, which again varies from sample to sample, depending on the properties and type. Hence, unlike most other facilities, there is no particular way of 'operation', that would lead to best possible result. It solely depends on experience with handling different type(s) of samples and hence it is recommended that somebody aiming to make TEM samples regularly should get trained, rather than depending on the TAs/staff-in-charge.
- Variable low speed Diamond saw is capable to cut the materials like ceramics, glasses and metals with high precision.
- Tuned Piezo Cutting Tool cuts the planner and cross-sectional samples with high precision without damaging it.
- Disc punch is capable to cut a specimen (only for metal sheets) discs of 3 mm in diameter and material thicknesses ranging from 10 μm to 100 μm.
- Disc grinder is an accurate and dependable tool for mechanically pre-thinning specimens with high quality and uniform thickness. The pre-thinning and polishing procedures reduce overall time and improve quality of the final specimen.
- Dimple grinder is used to dimple materials like ceramics and semiconductors below 3 μm with practically no mechanical damage and viewed subsequently in intermediate and high voltage TEMs without further thinning
- Precision Ion Polishing System (PIPS) is used as a final thinning or milling of the sample to provide electron transparent material for TEM analysis.
The quality of TEM images depends quite considerably on the sample preparation process, which involves thinning it down via cutting, grinding, dimpling and ion-milling to make the sample electron transparent. Care needs to be taken so that the sample preparation process does not affect properties of the material.
| Presented Date | Presentation File | Presentation by (Prof.) | Department | |
|---|---|---|---|---|
| 04-12-2017 | View Presentation1.78 MB | Prof. Amartya Mukhopadhyay | Metallurgical Engineering & Materials Science | |
| 08-10-2015 | View Presentation1.79 MB | Prof. Amartya Mukhopadhyay | Metallurgical Engineering & Materials Science | |
| 28-02-2019 | View Presentation2.23 MB | Prof. Amartya Mukhopadhyay | Metallurgical Engineering & Materials Science |
Minutes of the meeting of the TEM Sample preparation Facility Management Committee; held on October 21,2014 in the mini-conference room, 1st floor ME&MS, from 14:30 to 15:30.
The points that were agreed upon during the meeting are as follows:
1) It was decided that the number of tools (and corresponding spares) required for the manual grinding and ultrasonic cutting steps should be optimized so that they do not become the bottleneck and allow full utilization of the dimpler and PIPS.
2) In this light it was suggested to request IRCC for another set of Disc Grinder + Lapping kit (along with associated consumables), as this step takes up the major fraction of time. As per the presently received quotation, the cost would be ~ INR 4.5 to 5.0 Lakhs.
3) Since the ultrasonic cutter is subject to excess wear and tear and prone to break-down (of the tip), it was suggested to request IRCC for some additional spare tips. For the same, Prof Samajdar kindly volunteered to transfer this set-up (along with dimple grinder), presently located in SAIF to this central facility.
4) In order to expedite the overall rate of TEM sample preparation, it was suggested that the initial steps could be done in parallel for two users (with even the users contributing in some cases; under supervision of TAs), while another sample is being worked on in PIPS/dimpler. Basically, on all days at least one thinned sample should be ready and waiting to be loaded on these.
5) It was also decided to have the TAs prepare 2 to 3 samples per week, to reach the desired rate of at least 10 samples per week.
6) It was also agreed upon that we should try and invite more Central facilities TA from other departments and involve users in preliminary steps under supervision of TAs/Technical staff to improve our output and efficiency.
Members of the TEM Sample Preparation Facility user's committee:
Prof. Amartya Mukhopadhyay (MEMS)
Prof. Smrutiranjan Parida (MEMS)
Prof. N. Venkataramani (MEMS)
Prof. Rajiv O Dusane (MEMS)
Prof. Indradev Samajdar (MEMS)
Prof. Nithyanand Prabhu (MEMS)
Prof. Mahesh S Tirurnkudulu (CHE)
Prof. Sankara Sarma V Tatiparti (DESE)
Prof. Anil Kottantharayil (EE)
Prof. Sushil Mishra (ME)
Prof. S. S. Major (PHY)
- Maximum two samples are allowed in one slot, which can be either forenoon or afternoon of any working day. Please note that the actual time taken for TEM sample preparation can extend beyond the duration of a slot.
- Dimensions of the sample should be sufficient enough for TEM sample preparation.
- The user must be available during the TEM sample preparation process throughout.
- Maximum two samples are allowed in one slot, which can be either forenoon or afternoon of any working day. Please note that the actual time taken for TEM sample preparation can extend beyond the duration of a slot.
- Dimensions of the sample should be sufficient enough for TEM sample preparation.
- The user must be available during the TEM sample preparation process throughout.