Tuesday, July 03, 2018, 17:02

49 discs/ 15.42g np-SiC fibrous discs loaded into the tube container

Heat treatment is similar to previous process, see elog#408/409.

TGHt should be set at 330A/5.2V to reach temp 1575C (+/- 25C)

Omega slope set at 1.05 (for carbide)

Chamber is currently being pumped down

 Wednesday, July 04, 2018, 10:38

Pressure at 1.5 e-6 Torr.

Initiated auto-ramping at 0.2A/min to reach 330A/5.2V.

 Monday, July 09, 2018, 14:44

TGHT has been stabilized at 330A/5.2V for 24 hours.  Pressure at 3.7e-7 Torr.

Temp was measured at 1400C - light coating on window likely affected the measurements.

Measured with one-color pyrometer on Ta body inside the target container = 1550 C (with the correction of 250C for Ta). 

Adjusted OMEGA slope to 1.18, temp currently at 1580 C.

 Monday, July 09, 2018, 16:42

Pressure stabilized at 3.5e-7 Torr. 

Initiated auto-cooling at 1A/min.

 Tuesday, July 10, 2018, 11:11

Target is at room temperature. 

Process completed; see attachment for the data retrieval and dropbox (np-SiC production folder) for screen capture.

mass loss = (15.42 - 8.09) g = 7..33 g (47.5%) [in agreement - good!]

 Tuesday, September 11, 2018, 10:45:

TGHT: 53.4 A   TBHT: 57.75

Actual

TGHT: 60.0A  TBHT: 59.0A

Uploaded the rest to Word doc. Screenshots included.

 Monday, November 19, 2018, 08:57

Tantalum tube was coated with TaC and wrapped with Ta heat-shield (3 layers)

Desired temp = 1900 C (expected TGHT ~445A/7.5V), TBHT will be set fixed at 230A (max).

Pressure at IGP1 2.61-7 Torr. 

Tapped up TGHT and TBHT manually to 40 A

Waited ~1 hr for vacuum to stabilize.

IGP1 = 4.27e-7 Torr

Good vac at 3.00e-5 Torr

Bad vac at 5.00e-5 Torr.

Initiating auto ramp for TGHT @ 1 A/min to a max setpoint of 350 A

Once max setpoints achieved, will tap up manually to final desired temperature of 1900 C

Monday, November 19, 2018, 18:14

Temperature was 1755 C at 350 A

IGP1 = 9.28e-7 Torr

Tapped manually to 393 A (6.83 V)

IGP1 = 1.4e-6 Torr

Temperature 1904 C

The tube will stay at max current point overnight.

Tuesday, November 20, 2018, 08:17

 IGP1 = 9.28e-7 Torr

TGHT = 395 A, 6.98 V

Temperature 1903 C

Auto-ramp set to TGHT 0 A @ -2 A/min. 

 Thursday, November 22, 2018, 10:12

A previously sintered tantalum tube with 3 layers of shielding was loaded with a graphite insert.

The tube was loaded in evaporator 2 on Wednesday 21/11/2018 and pumped down

The graphite insert will be heated to 2000 C

current pressure IGP1 =  4.2e-7 Torr

TGHT manually tapped to 40 A

Autoramp set to 2 A/min on TGHT to 400 A aiming for 1800 C

 Thursday, November 22, 2018, 17:13

TGHT 401.25 A, 6.79 V

Temperature 1780 C

IGP1 7.89e-7 Torr

Tapping manually to reach 1800 C, final current 407.2 A, 6.96 V

  Friday, November 23, 2018, 17:13

 Tuesday, December 04, 2018, 07:53

TGHT 469.1 A, 8.814 V

Temperature 1983 C

IGP1 1.52e-7 Torr

Wednesday, December 05, 2018, 21:30

 TGHT 469.1 A, 8.75 V

Temperature 1983 C

IGP1 1.22e-7 Torr

Thursday, December 06, 2018, 12:25

 TGHT 468.9 A, 8.66 V

Temperature 1977 C

IGP1 1.42e-7 Torr

Friday, December 07, 2018, 17:59

  TGHT 468.9 A, 8.80 V

Temperature 1977 C

IGP1 1.42e-7 Torr

Wednesday, December 12, 2018, 12:18 

TGHT 469.2 A, 8.7 V

Temperature 1945 C

IGP1 1.10e-7 Torr

Thursday, December 13, 2018, 10:42

TGHT 469 A, 8.7 V

Temperature 1939 C

IGP1 1.04e-7 Torr

Ramping temperature down at -2 A/min

 Friday, December 14, 2018, 10:42

TGHT 0.0 A, 0.051 V

IGP1 4.36e-8 Torr

Thursday, December 20, 2018, 10:24

A tantalum tube was loaded in evaporator 2 on Wednesday 19/Dec/2018.

It is going to be heated to 2000 C during 3 weeks 

Pressure IGP1 =  4.88e-7 Torr

TGHT manually tapped to 40 A

Autoramp set to 2 A/min on TGHT to 400 A aiming for 1800 C

The system tripped due to a power outage.

the current went from 57 to 0 A.

The tube did not show damage signs.

 Tuesday, January 15, 2018, 17:30

Tantalum tube was coated with TaC and wrapped with Ta heat-shield (3 layers)

Desired temp = 1900 C (expected TGHT ~445A/7.5V), TBHT will be set fixed at 230A (max).

EVAP2 currently pumping down.

 Pressure at IGP1 4.71 -7 Torr. 

Tapped up TGHT manually to 40 A

Waited ~1 hr for vacuum to stabilize.

IGP1 = 9.96-7 Torr

Good vac at 3.00e-5 Torr

Bad vac at 5.00e-5 Torr.

Initiating auto ramp for TGHT @ 1 A/min to a max set point of 350 A

Once max set points achieved, will tap up manually to final desired temperature of 1900 C

 Thursday, January 17, 2019, 15:31

The tube remained at ~1900 C for 6 hours.

IGP1=5.8e-7 Torr

TGHT = 427 A, 7.23 V

Min Temperature = 1890 C

Thursday, January 17, 2019, 15:33

 Auto-ramp set to TGHT 0 A @ -2 A/min. 

 Wednesday, January 23, 2019, 13:01

A previously coated tantalum tube with 3 layers of shielding (Details in e-log 426) was loaded with a graphite insert. 

The tube was loaded in evaporator 2 and pumped down

The graphite insert will be heated to 2000 C for 3 weeks

 Thursday, January 24, 2019, 10:04

Pressure = 3.66e-7 Torr

TGHT manually tapped to 45 A

Final pressure = 3.8e-7 Torr

Set autoramp to 350 A @ 2A/min

TGHT = 1643 C

Set autoramp to 400 A @ 2A/min

TGHT = 1790 C

Started to tapped manually at approx 5 A every 30 s

Final TGHT => 1896 C, 8.16 V, 480.46 A

The current will stay at 480 A until temperature stabilizes. 

The current was reduced to 476 A to stay at 1900 C

Friday, January 25, 2019, 17:16

Pressure = 3.22e-7 Torr

TGHT = 8.17 V, 477.65 A, 1882 C 

Monday, January 28, 2019, 09:09 

Pressure = 1.67e-7 Torr

TGHT = 8.07 V, 477.65 A, 1859 C 

The temperature readings are fluctuating between 1880 and 1859 C

Tuesday, January 29, 2019, 07:32

Pressure = 1.55e-7 Torr

TGHT = 8.17 V, 477.75 A, 1880 C 

Tuesday, January 29, 2019, 11:34

 Pressure = 1.55e-7 Torr

TGHT = 8.27 V, 477.56 A, 1897C 

Tuesday, January 29, 2019, 12:47 

 Pressure = 1.53e-7 Torr

TGHT = 8.19 V, 477.75 A, 1899C 

Tuesday, January 29, 2019, 13:38

 Pressure = 1.55e-7 Torr

TGHT = 8.25 V, 477.75 A, 1905C

Thursday, January 31, 2019, 16:12  

 Pressure = 1.40e-7 Torr

TGHT = 8.4 V, 476.81 A, 1918C

Thursday, January 31, 2019, 22:32

Pressure = 1.39e-7 Torr

TGHT = 8.37 V, 476.71 A, 1914C

The current will be ramped down @1 A/min

Friday, February 01, 2019, 09:58

 Last 22 A tapped to 0 manually

Tantalum tube was removed from the EVAP2

Thursday, February 07, 2019, 14:12

Tantalum tube coated with TaC and wrapped with 3 layers of Ta heat-shielding.

Desired temperature= 1900 Celsius (expected TGHT ~445A/7.5V)

EVAP2 Currently pumped down, heating will be initiated tomorrow.

Friday, February 08, 2019, 08:46

Current pressure IGP1 = 3.46e-07 Torr

Manual tapping to 50A on TGHT

TGHT 47.43A, 0.26V

Waiting for pressure to stabilize.

Pressure was going down so current was increased manually to 65 A to induce the outgassing.

TGHT 73.9A, 0.67V

MAx pressure IGP1 = 4.41e-6 Torr

After approx 1 hour

TGHT = 0.70 V  74.1 A

IGP1 = 1.63 e-6 Torr

Autoramp was set to 2 A/min for final current of 350 A

 Friday, February 08, 2019, 13:43

Autoramp TGHT reached 350 A /5.47 V, current temperature at 1660 Celsius

IGP1 = 3.0e-06 Torr/coming down

Increase TGHT to 400 A autoramp at 2A/min

 Friday, February 08, 2019, 14:39

TGHT reached 413 A, 6.8 V, pressure at 1.9 e-06 Torr coming down

Continue to tap up TGHT to reach 1900 C

Friday, February 08, 2019, 14:56

TGHT manually increased to 428 A, 7.18V, pressure at 2.0e-06 Torr coming down slowly

Temperature at 1903 C

Will continue to heat at ~1900 C for four hours before cooling down

 Friday, February 08, 2019, 21:00

TGHT 7.21 V, 429.75 A, 1873 C

IGP1 6.77e-7 Torr

The heater ramp is set to -2 A/min to 0 A.

 Wednesday, February 13, 2019, 10:04

A previously coated tantalum tube with 3 layers of shielding (Details in e-log 426) was loaded with a graphite insert. 

The tube was loaded in evaporator 2 and pumped down

The graphite insert will be heated to 2000 C for 1 week

IGP1=1.37e-07 Torr

 Wednesday, February 13, 2019, 10:27

IGP1= 1.46e-07 Torr

Manual tapping to 40A on TGHT

TGHT 40.7A, 0.104V

Autoramp started at 1A/min up to 400 A

Good Vacuum = 3.00e-05, Bad Vacuum = 5.00e-05

 Thursday, February 14, 2019, 08:42

IGP1= 2.2e-07 Torr, T=1705 C, TGHT 401A, 6.7 V

Manually tapping to 2000 C (Slow ~1 A/min) in 5 A increments followed by waiting for equillibrium

Thursday, February 14, 2019, 10:54

IGP1 = 1.4e-06 Torr, T = 2003 C, TGHT 500A, 9.1 V

Waiting for equillibrium

manually tapped TGHT to 503A,  T = 2003 C

Will leave for 1 week

Wednesday, February 20, 2019, 08:44

 IGP1= 1.37e-07 Torr, T=1943 C, THGT= 503 A, 8.9 V

Ramp-down @ 2A/min

Wednesday, February 20, 2019, 14:02  

1 hour since TGHT = 0 A

Venting will proceed.

 Wednesday, March 13, 2019, 15:41

An uncoated tantalum tube was loaded with a graphite insert (with conical caps).

3 tantalum foils were wrapped around the tantalum tube and a Ta cap was added.

EVAP2 is currently pumping down

The tube will be hated for 5 days at 2000 C

Thursday, March 14, 2019, 10:07

IGP1 = 5.37e-7 Torr

The TGHT will be tapped manually to 50 A  

After aprox 1 hour IGP1 = 5.08e-7 Torr, TGHT=46.5 A, 0.224 V

Autoramp is set to 1A/min to 300 A

 Autoramp is set to 1A/min to 450 A

Autoramp was stopped at 425 A when 2000 C were achieved

 Sunday, March 17, 2019, 00:25

IGP1 = 2.03e-7 Torr

TGHT=424.2 A, 7.117 V, temp 1976 C

Sunday, March 17, 2019, 15:04 

IGP1 = 21.6e-7 Torr

TGHT=424.1 A, 7.085 V, temp 1967 C

cooling down -1 A/min

Monday, April 01, 2019, 16:35

Container was coated with TaC and a roll of graphite inserted inside the tube.   A couple of TaC coated Ta springs inside to keep graphite pressed against walls of cylinder.

Container wrapped with 2 Ta heat shields.

Desired temp = 1900 C, Omega slope set = 0.990, Auto ramping TGHT at 1A/min to reach 400A, TGHT will be tapped up accordingly to reach desired Temp.

Good vac at 3.00-5 Torr

Bad vac at 5.0e-5 Torr.

Chamber is currently being pumped down.  Sintering will proceed tomorrow.

Tuesday, April 02, 2019, 06:27

IGP1 = 4.37e-7 Torr

Current is manually tapped to 40 A

Tuesday, April 02, 2019, 08:12 

Pressure increased to IGP1 = 1.15e-5 Torr

and it stabilized to IGP1 = 2.32e-6 Torr after ~1.5 hrs

Autoramp is set to 1 A/min to 400 A

Tuesday, April 02, 2019, 08:45

Autoramp stopped momentarily, to stop current reduction

When pressure reduced to ~4e-5Torr, current was tapped manually to 50 A

Autoramp is set again, the conditions are

IGP1 = 2.5e-5 Torr

TGHT = 58.87 A, 0.36 V

Tuesday, April 02, 2019, 09:31

Autoramp stopped momentarily, to avoid current reduction

When pressure reduced, autoramp is set again,

the conditions are:

IGP1 = 2.9e-5 Torr, TGHT = 0.52 V, 71.5 A 

 Tuesday, April 02, 2019, 15:32

 Autoramp stopped momentarily, to avoid current reduction

conditions: IGP1=4.99e-5 Torr, TGHT = 0.78 V, 85.9 A

When pressure reduced, autoramp is set again,

 Tuesday, April 02, 2019, 22:37

Camera conexion was lost

Autoramp reached 400 A

the current was manually raise to 425 A to allow the completation of the process

Wednesday, April 03, 2019, 00:27

Camera connection still off

The current was reduced to 410 A to match with the estimated temperature 

Wednesday, April 03, 2019, 06:56

Camera connection is back, temperature reading is 1786 C

IGP1  5.01e- Torr

TGHT = 6.93 V, 412.22 A

Autoramp was set to -1A/min to 0A

Wednesday, April 03, 2019, 11:01

IGP1 = 1.67e-7 Torr

TGHT = 2.25 V, 179.53 A

Autoramp changed to -2 A/min 

Wednesday, April 03, 2019, 16:54

The tube was removed from the EVAP2,

The coating has a different color than regular coatings, but it doe not seem like the graphite adhered as expected. 

 Wednesday, April 03, 2019, 16:57

Tantalum tube was coated with TaC and wrapped with Ta heat-shield (3 layers)

Desired temp = 1900 C (expected TGHT ~445A/7.5V).

EVAP2 currently pumping down.

 Thursday, April 04, 2019, 05:12

IGP1 = 4.5e-7 Torr

The current is tapped manually to 40 A

After1 hour IGP1 = 1.18e-6 Torr, the autoramp was set to 1 A/min to 400 A

Thursday, April 04, 2019, 18:58

After 4 hours at ~1900 C:

IGP1 = 6.13e-7 Torr 

TGHT = 6.74 V, 416.06 A

 Sunday, April 07, 2019, 08:10

A graphite insert (with conical caps) was loaded in tantalum tube previously coated with TaC,

and wrapped with 3 tantalum foils,

a tanalum cap was inserted in one side of the Ta tube and sealed.

The tube was set in the EVAP2 and the furnace was pumped down.

IGP1 = 1.24e-7 Torr.

The current was tapped to 40 A

Autoramp was set to 1 A/min to 300 A.

At TGHT 335.53 S, 5.28 V the temperature was 1560

The autoramp was set to 450 A.

At TGHT 474.75 S, 7.96 V the temperature was 1560

The autoramp was set to 450 A.

To reach 2000 C, TGHT = 500.25 A, 8.45 V.

After 1hr the temperature stabilized to 1959 C

and the  current was increased to TGHT = 510.28 A, 8.64 V.

After stabilization the temperature reached 2010 C.

The current was decreased to TGHT = 503.15 A, 8.45 V

and the temperature stabilized to 2001 C.

The voltage increased  unexpectedly to 8.89 V and the temperature increased to 2055,

the current was reduced to keep the tube at 2000 C.

The voltage kept increasing and we kept decreasing the current to keep the tube at 2000

The final current before venting and getting out the container was

TGHT = 466.219 A and 8.467 V.

Test result: Broken tantalum tube.

 Tuesday, April 16, 2019, 13:38: Replaced the bottom insert on the heat shield. 

Used small amount of isopropyl alcohol to wipe the inside if the HS out. 

 Friday, May 10, 2019, 16:54

A tantalum tube was coated with TaC,and wrapped with three tantalum sheets,

the tube was set in the EVAP2 to sinter the TaC coating.

EVAP2 is currently pumping down. 

 Sunday, May 12, 2019, 18:40

IGP1 = 3.01e-7 Torr

Manually tapped current TGHT to 40 A

IGP1 = 4.89e-Torr

at the IGP1 = 1.961e-6 Torr the autoramp was set to 1 A/min to 380 A

IGP1 = 6.91e-7 Torr

TGHT = 6.133 V, 386.8 A, temperature 1682  C

IGP1 = 7.77e-7

TGHT=6.36V, 399A 1730 C

After 4 hours at 1895 C TGHT = 7.435 V and 445.781 A

TGHT was set -2 A/min to 0 A

The EVAP2 was vented with air and the tube was removed

 Tuesday, May 21, 2019, 14:33: Install flexible line evap 2 HS.

 Tuesday, May 21, 2019, 17:57

A tantalum tube previously coated with TaC and sintered was loaded with graphite foils.

The mass of the foils was 20.04 g.

The system will be heated to 2000 C to find out the corresponding current.

After that the tantalum tube will be trasferred to the EVAP1

and it will be heated there for 5 days. 

EVAP2 currently pumping down

 Thursday, May 23, 2019, 05:48

IGP1 = 2.516e-7 Torr

Manually tap to 50 A

Autoramp set to 1 A/min to 400 A

Thursday, May 23, 2019, 13:09 

IGP1 = 3.78e-6 Torr

TGHT = 6.4 V, 401.3 A

Temperature reading = 1629

Thursday, May 23, 2019, 13:09

Autoramp was set to 550 A at 1 A/min 

Stopped at 530 A

Thursday, May 23, 2019, 21:27

IGP1 = 6.77e-7 Torr

TGHT = 9.2175 V, 507.375 A

After 6 hours at ~2000 C the autoramp was set to -2 A/min to 0 A 

Friday, May 24, 2019, 8:46

EVAP2 was vented with air and the tantalum tube was removed, examined and transferred to EVAP1

Friday, May 24, 2019, 15:26

 A graphite insert with tantalum wires in its caps

was loaded in a tantalum tube, the system will be heated to 2000 C

and after 6 hrs at that temperature, it will be cooled and heated to 2000 C again.

The temperature will be hold at 2000 C for a 6 days.

Currently the chamber is being evacuated.

 Saturday, May 25, 2019, 06:01

IGP1 = 2.2e-7 Torr

Manually tapping to 50 A

Autoramp set to 1 A/min to 400 A

Saturday, May 25, 2019, 13:37

The autoramp was set to 450 A

Then it was manually tappe to 475 A 

Thursday, June 6, 2019, 16:43

A graphite insert with tantalum wires in its caps was loaded in a tantalum tube.

The system will be heated to 2000 C again (see elog 446)

Currently the chamber is being evacuated.

Friday, June 7, 2019, 16:40

Autoramp was set to 450 A at 1A/min to reach 2000 C

The temperature will be hold at 2000 C for a 4 days.

Tuesday, June 11, 2019, 16:46 

Autoramp is set to -2 A/min to 0 A

Wednesday, June 12, 2019, 17:01 

The tube present sever crystallization but is not broken and has some resistance against pressure.

Wednesday, August 28, 2019, 06:00

A graphite insert (with conical caps) was loaded in tantalum tube 

the Ta tube was wrapped with 3 tantalum foils,

a tantalum cap was inserted in one side of the Ta tube and sealed.

The tube was set in the EVAP2 and the furnace was pumped down.

IGP1 = 1.23e-6 Torr.

The current was tapped to 50 A

Autoramp was set to 1 A/min to 400 A.

 Wednesday, August 28, 2019, 12:02

Autoramp reached 400 A

TGHT = 6.57 V, 404.4 A, IGP1=4.7e-6 Torr

Autoramp was set to 450 A at 1A/min

 Wednesday, August 28, 2019, 12:48

Autoramp reached 450 A

TGHT =7.526 V, 450.188 A, IGP1=5.88e-6 Torr

Autoramp was set to 500 A at 1A/min

Wednesday, August 28, 2019, 13:40

Autoramp reached 500 A, temperature 1880 C

TGHT =8.79 V, 501.094A, IGP1=7.48-6 Torr

Autoramp was set to 540 A at 1A/min 

Wednesday, August 28, 2019, 14:03

The autoramp was stopped at 520 A, because according to previous tests that current is enough to have 2000 C,

the temperature read was 1930 C

TGHT =9.23 V, 520.7 A, IGP1=7.8-6 Torr

Wednesday, August 28, 2019, 15:20

The autoramp was set to 540 A at 1A/min

When the ramp stopped the conditions were:

TGHT=9.59 V, 539.5 A, IGP1= 6.08e-6 Torr

Temperature= 1988 C

Manually tapped to 545 A the temperature reached 2000 C

Wednesday, August 28, 2019, 17:08 

To keep the temperature at 2000 or less the current was decreased,

TGHT= 8.91 V, 445.125 A, IGP1=9.93e-7 Torr

Max temperature read: 2001 C

Min temperature read: 1996 C

Tuesday, September 03, 2019, 11:15

The tube was stable at 1950-1960 C during the weekend but today at around 6 am it had a drop in the current indicating mechanical failure 

The autoramp was set to -2A/min to 0 A. 

The tube will be examined and in case that it is not broken it will be set in the EVAP1 to continue heating it.

Monday, September 09, 2019, 16:35  

The tube became brittle and broke.