School of Engineering Sciences and Technology (SEST) 

University of Hyderabad (UoH)

Prof. C. R. Rao Road, CUC, Gachibowli,

Hyderabad, Telangana 500046, India

copyrights@Dibakar Das

visitors 

Exploring the Materials Properties

Microwave furnace with Controller   

Make: 

Linn High. Therm (MKH-4,8  Microwave high temperature chamber furnace, Germany)

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Use of microwave power for sintering of ceramics leads to faster heating rates, low processing times and enhanced densification rates leading to uniform microstructure compared to those obtained using conventional sintering. It is generally seen that electrically insulating ceramics are poor absorbers of microwaves at room temperature. Dielectric losses of such ceramics increase with increasing temperature and start coupling with microwaves beyond a certain critical temperature Tc. Hence, insulating ceramics are sintered by hybrid heating, where susceptors are used to increase the temperature of the material upto the critical temperature Tc.

 

Technical key Data:

 

  1. Temperature range- 900  to 1700 °C.

  2. Microwave supply through independent 900 Watt magnetrons

  3. Microwave susceptors (SiC) for indirect sample preheating

  4.  Potentiometer for step less power adjustment 15 - 100 % 

Fast Firing Furnace

Make: OKAY (70F4), India

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Fast firing furnaces are very useful tool for rapid heating of the ceramic samples. Fast firing of ceramics  have attracted lot of research attention as the conventional firing is very time consuming. The temperature could be raised quite fast and the firing of materials is finished within few minutes.

Technical key Data:

  1. Light- weight, compact and portable furnace 

  2. Fast-heating up to 1600 °C in 30 minutes.

  3. Fast cooling makes possible several cycles

  4. Built-in transformer and control panel

Automated Chemical Mechanical Polisher 

Make: 

Buehler (Ecomet 250 variable speed Grinder Polisher with Automet 250  power head, USA)

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CMP is a tool used to planarize the semiconductor wafer surfaces. The CMP process combines the chemical (acidic or basic) effect of the slurry, which contains micro-abrasives, with the mechanical effect provided by polishing to reduce the roughness on the wafer surfaces.

Optical Surface Profiler

Make: 

Bruker (Model: Contour GT-K0, USA)

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Optical surface profiler is a Non-contact interference microscopy, where height variations (surface roughness) on the sample surfaces can be measured with good precision using the wavelength of light as the ruler.

 

 

 

 The Mode of Operation: 

The phase-shifting interferometry (PSI) mode allows measuring fairly smooth and flat surfaces (surface roughness from few Angstrom to ~30 nm) while the vertical scanning interferometry (VSI) mode can measure relatively rough surfaces (surface roughness from ~30 nm to few microns).

 

Technical Key Data:

  1. XY Sample Stage: 150mm (6in) manual; ±6º manual tip-tilt in system base Optional programmable 150mm  motorized.

  2. Z Focusing Stage:  100mm manual Z axis

  3. Optical Assembly Module: Dual-LED illumination source 

  4. Max. Scan Speed: 28.1μm/sec

  5. Z Scan Range: 0.1nm to 10mm

Rheometer

Make: 

Anton Paar (MCR 102, Austria)

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Rheometer is used to study rheological properties of colloidal materials for ceramic and other materials processing.

 

Technical Key Data:

1) Temperature control unit (TCU) by Peltier system for plate/cone:  -40 C to +200 °C

2) Pressure: 1-300 atm

3) Modes: rotational and oscillatory

4) Normal force range 0.01-50 (+0.005) N,

5) Shear stress measurement in 2 modes:

– shear velocity control

– shear stress control.

P-E loop Measurement System 

Make:

MARINE India (PE-01, PE loop Tracer System, India)

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The basic PE test system is based on sawyer tower circuit. The principle is simple when two capacitors are connected in series and AC voltage is applied on both in series, the charge on both will be same. In order to get complete saturation the internal capacitance must be bigger than the sample capacitance.

Measurements: P-E loop at different temperatures at variable frequencies, different frequencies at variable temperatures, P-E fatigue at variable temperature and frequencies 

 

 

Technical Key Data:

 

1) Filed : 5KV

2) Frequency range: 20 Hz to 1 KHz

3) Fatigue: upto 20th order of cycle

4) Temperature range: RT to 400 °C with PID control

Poling Set-up

Make: Home made 

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Electric poling is usually done to ferroelectric ceramics to improve their piezoelectric properties, which is actually a process of domain reorientation induced by an external electric field.

 

 

Magnetostriction Equipment

Make: 

FERRITES INDIA  (P3 Strain indicator for strain gauge, India)

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Resistance of the metallic material changes when elongated or contracted. Based on this principle strain gauge is operated for measuring the strain. Strain gauge is rigidly bonded on the specimen to measure the change in length (contraction or elongation). Electrical resistance is proportional to the change in length. By measuring the change in resistance the strain developed in the specimen can be estimated. The change in resistance of the strain gauge (∆R) to the original resistance R is related to the dimensional change (∆L/L) of the specimen as follows,

 

 

Where, k is called the gauge factor related to the sensitivity of the strain gauge, ∆L is change in length, and L is the original gauge length. Change in resistance of strain gauge is measured by a digital read out box (P3 meter) of the Bridge circuit.

Technical key Data:

  1. Field in 10mm gap : 12kA/cm (gap adjustable: 0-60mm) .

  2. .Filed measurement: 'H' axis(soft) through Hall sensor range selection.

  3. Number of ranges : 2& 20kA/cm.

  4. Pole size : 90mm .

School of Engineering Sciences and Technology (SEST) 

University of Hyderabad (UoH)

India.

LABORATORY OF FUNCTIONAL CERAMIC MATERIALS

Prof. Dibakar Das Research Group