Monday, November 23, 2015, 14:29

No heat shields.

Container empty.

Loaded into evap2 and currently pumping down.

 Tuesday, November 24, 2015, 09:36

HS water valves opened this morning, no leaks detected.

IGP1 = 4.5e-7 Torr.

Changed slope of OMEGA IR to 0.98 for empty container.

Tapped up manually to 35A.

IGP1 = 4.7e-7 Torr.

Vacuum stable, initiating auto-ramp at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Final setpoints: TBHT = 230A, TGHT = 300A

Will tap up manually to 2000C

 Tuesday, November 24, 2015, 14:00

TGHT = 300A, 3.75V

TBHT = 230A, 3.08V

IGP1 = 4.7e-7 Torr

No reading yet on the OMEGA.

Re-initiating auto-ramp to final setpoint TGHT = 450A

 Wednesday, November 25, 2015, 09:11

IGP1 = 3.0e-7Torr.

TGHT = 450A, 6.37V

Tapping up manually to 2000C

 Wednesday, November 25, 2015, 15:31

container was tapped up manually to 650A, slope/emissivity settings were checked.

ramped back down to 450A and tapped up manually while recording data up to 1800C [legs = 2000C]

once reached 1800C, tapped TBHT down manually to see relation of TBHT to temperature/ TGHT

remained at 1800C for ~1hr [while tapping down TBHT] before initiating auto-cool at 2.0A/min for the TGHT

see attachment for raw data.

 Thursday, November 26, 2015, 10:08

Vented in air and took out this morning.

 Monday, November 30, 2015, 15:37

No heat shields.

Container empty.

Loaded into evap2 and currently pumping down.

Tuesday, December 01, 2015, 10:07 

HS water valves opened this morning, no leaks detected.

IGP1 = 4.3e-7 Torr.

Slope of OMEGA = 0.98

Tapped up manually to 35A.

Vacuum stable, initiating auto-ramp at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Final setpoints: TBHT = 90A, TGHT = 360A

Once final setpoints reached, will tap up manually to max 1800C [legs = 2000C]

 Monday, December 07, 2015, 09:06

Container was tapped up manually with emissivity measurements taken every 50A starting at 360A.

The final measurement was taken at 640A.

Container was ramped down for the weekend.

See attachment for raw data.

 Data from thermocouple attached. Raw data and Excel sheet with plot.

 Monday, December 07, 2015, 09:04

No heat shields.

Container empty.

IGP1 = 1.1e-7 Torr.

Slope of OMEGA = 0.98

Tapped up manually to 35A.

Vacuum stable, initiating auto-ramp at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Final setpoints: TBHT = 90A, TGHT = 360A

Will tap up with the same parameters as last round to confirm results.

 Friday, December 11, 2015, 11:44

Took out of evap2 yesterday.

Aurelia took many emissivity measurements to compare with previous data - which matched up.

The dip in emissivity before going up again around ~560A could be due to oxidation of the materials.

 Friday, February 12, 2016, 11:01

Container coated with TaC with new method - ends tapped off,  liquid poured/swirled around container, then poured back out - 'flushing technique'.

Container wrapped with 3 x Ta heat shields, incl center block - new method of each layer being one long single Ta foil covering entire container incl center block

IGP1 = 6.3e-7Torr

HS water valves opened, no leaks detected.

Tapped up manually to 35A.

Waited ~20min.

Vacuum stable, IGP1 = 1.3e-6 Torr.

Initiated auto-ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively with final setpoints of 400A and 230A.

 Monday, February 15, 2016, 08:56

IGP1 = 3.9e-7 Torr.

TBHT = 230A, 4.0V

TGHT = 400A, 6.58V

OMEGA = 1766C

Tapping up manually to 1900C...

 Monday, February 15, 2016, 10:18

IGP1 = 5e-7 Torr

TGHT = 450A, 7.55V

OMEGA = 1913C

 Monday, February 15, 2016, 14:30

IGP1 = 4.9e-7 Torr.

TGHT = 450A, 7.55V.

Material remained at ~1910C for ~4hrs.

Initiating auto-cool at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

 Tuesday, February 16, 2016, 14:17

vented in air and opened up this morning.

target container sintered nicely.

 Tuesday, February 16, 2016, 14:19

coated with TaC yesterday and let dry overnight.

wrapped with one long Ta heat shield - wrapped around tube 3x, with Ta wire to offset Ta foil away from container

loaded into evap2 and currently pumping down.

 Wednesday, February 17, 2016, 10:51

HS water valves opened, no leaks detected.

Tapped up manually to 35A.

Waited ~20min, vacuum stable.

IGP1 = 5.9e-7 Torr.

Initiating auto-ramp at 0.2A/min to a final setpoint of 400A.

Final desired temperature = 1900C

 Thursday, February 18, 2016, 09:16

IGP1 = 6.6e-7 Torr.

TGHT = 303A, 4.3V

OMEGA = 1311C

Increasing ramping rate to 1.0A/min.

Laura Lambert wrote:

Tuesday, February 16, 2016, 14:19 coated with TaC yesterday and let dry overnight. wrapped with one long Ta heat shield - wrapped around tube 3x, with Ta wire to offset Ta foil away from container loaded into evap2 and currently pumping down.  Wednesday, February 17, 2016, 10:51 HS water valves opened, no leaks detected. Tapped up manually to 35A. Waited ~20min, vacuum stable. IGP1 = 5.9e-7 Torr. Initiating auto-ramp at 0.2A/min to a final setpoint of 400A. Final desired temperature = 1900C  Thursday, February 18, 2016, 09:16 IGP1 = 6.6e-7 Torr. TGHT = 303A, 4.3V OMEGA = 1311C Increasing ramping rate to 1.0A/min.

 Thursday, February 18, 2016, 13:10

TGHT reached to 450A, temp at 1800C.  Stepped up TGHT 490A, temp measured at ~1900C. 

John Wong wrote:

Laura Lambert wrote:  Tuesday, February 16, 2016, 14:19 coated with TaC yesterday and let dry overnight. wrapped with one long Ta heat shield - wrapped around tube 3x, with Ta wire to offset Ta foil away from container loaded into evap2 and currently pumping down.  Wednesday, February 17, 2016, 10:51 HS water valves opened, no leaks detected. Tapped up manually to 35A. Waited ~20min, vacuum stable. IGP1 = 5.9e-7 Torr. Initiating auto-ramp at 0.2A/min to a final setpoint of 400A. Final desired temperature = 1900C  Thursday, February 18, 2016, 09:16 IGP1 = 6.6e-7 Torr. TGHT = 303A, 4.3V OMEGA = 1311C Increasing ramping rate to 1.0A/min.    Thursday, February 18, 2016, 13:10 TGHT reached to 450A, temp at 1800C.  Stepped up TGHT 490A, temp measured at ~1900C.

Thursday, February 18, 2016, 17:21

TGHT remained at max setpoint for 4hrs.

IGP1 = 6.6e-7 Torr.

OMEGA = 1913C

Initiating auto-cool for TGHT at 2.0A/min.

 Friday, February 19, 2016, 14:17

evap2 vented and opened up this morning.

container looks good.

Tuesday, April 26, 2016, 13:32

Container coated with TaC using 'flushing technique'.

Wrapped with 3 x Ta heat shields, incl center block - new method of each layer being one long single Ta foil covering entire container incl center block

Currently pumping down in evap2

 Wednesday, April 27, 2016, 10:25

IGP1 = 2.6e-7 Torr.

HS water valves opened, no leaks detected.

Tapped up manually to 35A.

Waited ~35min

Vacuum stable, IGP1 = 6.7e-7 Torr

Initiated auto-ramp at 0.2A/min for the TGHT with a final setpoint of 400A

Final desired temperature = 1900C

 Thursday, April 28, 2016, 14:41

Previously TBHT not on when sintering IGLIS container [since no ionizer tube] - John decided will turn on for this round

Tapped up TBHT manually to 140A, 1.69V

IGP1 = 4.5e-7 Torr

OMEGA = 1635C

TGHT = 382A, 5.8V

Initiating auto-ramp of TBHT at 0.1A/min with a final setpoint of 230A.

Friday, April 29, 2016, 08:40

IGP1 = 2.22-7 Torr

TGHT = 400A, 6.1V

TBHT = 233A, 2.9V

OMEGA = 1719C

Tapping up manually to OMEGA = 1900C

Friday, April 29, 2016, 15:22

IGP1 = 3.0e-7 Torr

TGHT = 460A, 7.52V

TBHT =230A, 2.93V

OMEGA = 1904C

Target container has remained at max temperature setpoint of 1900C for 4.5hrs.

Initiating auto cool for TGHT and TBHT at 2.0A/min and 1.0A/min respectively.

 Monday, May 02, 2016, 08:35

Vented in air and opened up this morning.

Container looks good.

See attached photos.

 Wednesday, May 25, 2016, 11:37

Container coated with TaC using 'flushing technique' [cleaned ionizer tube with acetone, so no coating inside ionizer tube]

Wrapped with 2 x Ta heat shields - one full height of Ta foil wrapped around cooling fins twice

Currently pumping down in evap2

 Thursday, May 26, 2016, 09:28

Tapped up manually to 40A

IGP1 = 6.6e-7 Torr

Initiating auto-ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively.

Final setpoints for TGHT = 650A and TBHT = 230A

Once max setpoints reached will continue to tap up manually while monitoring temperature to 1900C

Laura Lambert wrote:

Wednesday, May 25, 2016, 11:37 Container coated with TaC using 'flushing technique' [cleaned ionizer tube with acetone, so no coating inside ionizer tube] Wrapped with 2 x Ta heat shields - one full height of Ta foil wrapped around cooling fins twice Currently pumping down in evap2  Thursday, May 26, 2016, 09:28 Tapped up manually to 40A IGP1 = 6.6e-7 Torr Initiating auto-ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively. Final setpoints for TGHT = 650A and TBHT = 230A Once max setpoints reached will continue to tap up manually while monitoring temperature to 1900C

 Tuesday, May 31, 2016, 11:09

TGHT at 615A/9.08V, temp = 1610C.  Vacuum at 1.8e-7 Torr. 

Tapping up TGHT to reach 1900C

 Tuesday, May 31, 2016, 12:04

TGHT at 765A/11.90V.  Temp at 1900C.  Pressure is coming down from 8.7e-7Torr. 

Will keep at this temperature for a day.

 Wednesday, June 01, 2016, 15:22

Temperature has been stable at 1900C.  Pressure is coming down from 3.4e-7 Torr. 

Cooling down TGHT and TBHT at 2A/min and 1A/min, respectively.

 Friday, June 03, 2016, 12:10

TGHT/TBHT at 0A.  Target can be remained under vacuum until Monday.

 Monday, June 06, 2016, 16:54

Target container was inspected; it looks good

 Monday, June 27, 2016, 11:07

Container coated with TaC using 'flushing technique'.

Wrapped with 3 x Ta heat shields, incl center block - new method of each layer being one long single Ta foil covering entire container incl center block

Currently pumping down in evap2

 Monday, June 27, 2016, 13:23

HS water valves opened

Tapped up manually to 35A

Waited ~1hr, vacuum stable

IGP1 = 1.8e-6 Torr

Initiating auto ramp for TGHT @ 0.2A/min to a max setpoint of 400A

Initiating auto ramp for TBHT @ 0.1A/min to a max setpoint of 230A

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

 Wednesday, June 29, 2016, 11:33

IGP1 = 1.9e-7

TGHT = 400A, 6.0V

TBHT = 223A, 3.9V

OMEGA = 1885C

Remained at these settings for ~13hrs

Increased TBHT max voltage to 4.3V to achieve 230A

TBHT = 230A, 4.1V

OMEGA = 1890C

Tapped up to TGHT = 405A, 6.17V to achieve 1900C...OMEGA reached 1915C

Lowered TGHT to = 403A, 6.12V

OMEGA = 1905C

Measured ~1870C with the mikron, same window the OMEGA measurements are taken out of.

IGP1 = 2.1e-7

 Thursday, June 30, 2016, 08:44

TGHT = 403A, 6.07V

OMEGA = 1886C

Tapped back up to 1900C

TGHT = 410A, 6.22V

OMEGA = 1911C

Thursday, June 30, 2016, 16:01

OMEGA = 1911C

Container has remained at ~1900C for ~1.5 days

Initiating auto-cool at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

 Monday, July 04, 2016, 09:59

Vented in air and opened up this morning.

Container looks good.

Confirmed coating fully sintered with J.Wong.

Photos attached.

 Friday, July 15, 2016, 11:49

Container previously coated with TaC using 'flushing technique', cleaned ionizer tube with acetone, so no coating inside ionizer tube

Wrapped with 3 x Ta heat shields, incl center block - new method of each layer being one long single Ta foil covering entire container incl center block

Currently pumping down in evap2

 Friday, July 15, 2016, 14:35

Turbo pump broken 

Currently being replaced...

 Friday, July 15, 2016, 17:04

Turns out its not the turbo pump...TP controls and pump replaced, problem still happening.

Took out heat shield and used a closed loop to rule out leak in chamber, emptied all water lines - turbo pump now on.

Took v.long time to pump down. TP will remain on over wknd.

BP turns on, PV1 turns on, RV turns on - then takes very long time for vacuum to drop ~45min? before BV and TP can be turned on.

Possibly problem with threads on heat shield and not creating proper seal?

Will continue monday with evap2 mystery problem solving...

Monday, July 18, 2016, 16:14

Replaced heat shield and copper seals.

Container re-loaded.

Turbo pump on and good vacuum achieved! YAY!

Finished pumping down, opened HS water valves - no leaks detected.

Tapped up manually to 35A

Vacuum stable, IGP1 = 3e-6 Torr

Initiating auto ramp for TGHT @ 0.2A/min to a max setpoint of 400A

Initiating auto ramp for TBHT @ 0.1A/min to a max setpoint of 230A

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

 Tuesday, July 19, 2016, 09:21

TGHT = 242A, 2.76V

TBHT = 162A

IGP1 = 5.05e-6 Torr

Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.

 Tuesday, July 19, 2016, 13:04

TGHT = 400A, 4.4V

TBHT = 230A, 2.6V

OMEGA = 1120C

Reached max setpoints ~1hr ago.

Tapping up manually to 1900C...

Tuesday, July 19, 2016, 16:32

MORE problems with evap2 

TGHT reads 460A, 5.1V, 1170C - a lot of power is being lost somewhere...

Comparison from elog i.d. 291 [the last IGLIS container sintering of TaC coating] the TGHT read 460A, 7.5V, 1900C

Another problem: the read out on the power supply and read out on epics of the TBHT reads 215A; however, the 'current set' says 177A - two very different numbers?!

Ramping down evap2 at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively to further inspect chamber and hopefully solve this...

 Wednesday, July 20, 2016, 13:34

Chamber was vented in air and opened up for inspecting.

Fixed!

One of the steel plates used to stop reflection onto the door of the chamber was inserted improperly, resting on top of the 2 negative copper lines to the target leg, this was causing a short.

There was also a short from the right target leg touching the copper heat shield, the heat shield has been shaved down and corrected. It is no longer touching.

There were also 2 brackets that had fallen behind evap2 inside the cage, one was touching the positive lines - it wasn't quite touching the ground, but may have grounded it, causing another possible short.

The chamber was pumped back down and the HS water valves re-opened. No leaks detected.

Evap2 was tapped up manually to 35A.

Vacuum stable = 1.0e-6 Torr.

Initiating auto-ramp at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Final setpoints are TGHT = 400A and TBHT = 230A

 Wednesday, July 20, 2016, 16:25

TGHT = 315A, 4.5V

TBHT = 174A, 2.1V

IGP1 = 2e-6 Torr

OMEGA = 1518C

Lowering auto-ramp to 0.2A/min and 0.1A/min for the TGHT and TBHT overnight while unable to keep watch on the vacuum.

 Thursday, July 21, 2016, 09:09

Evap 2 reached max setpoints ~7.5hrs ago.

TGHT = 400A, 6.3V

TBHT = 230A, 2.9V

IGP1 = 5.1e-7 Torr.

OMEGA = 1882C

Tapping up manually to 1900C...

 Friday, July 22, 2016, 16:18

Container has remained at ~1900C for ~31hrs

TGHT reached 405A/1900C - then after ~23hrs dropped in temperature down to 1895C so was tapped up further to 410A/1910C for another ~8hrs.

TGHT = 410A, 6.57V

IGP1 = 3.1e-7 Torr

TBHT = 230A, 2.9V

Initiating auto-cool at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Will remove from evap2 after the weekend.

 Tuesday, July 26, 2016, 16:49

vented in air.

container looks good, fully sintered.

will update with photos tomorrow...

 Wednesday, August 17, 2016, 17:30

Container coated with TaC using 'flushing technique', cleaned ionizer tube with acetone, so no coating inside ionizer tube

Wrapped with 3 x Ta heat shields, incl center block

Currently pumping down in evap2

Thursday, August 18, 2016, 10:14 

HS water valves opened...leak detected  see attachment for photo from archives

Vented and opened up.

Anders performed leak check, nothing found.

Replaced all seals with blue seals.

Pumping down now

 Thursday, August 18, 2016, 16:12

HS water valves opened...leak detected again  see attachment for photo of striptool

Vented and opened up.

working with Anders on finding leak...

 Monday, August 22, 2016, 10:38

leaks FIXED!

HS water valves opened, NO leaks detected!

Tapped up manually to 70A

Vacuum stable, IGP1 = 2.5e-6 Torr

Initiating auto ramp for TGHT @ 0.2A/min to a max setpoint of 350A

Initiating auto ramp for TBHT @ 0.1A/min to a max setpoint of 230A

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

 Monday, August 22, 2016, 14:58

TGHT = 115A, 1.3V

TBHT = 89A, 0.97V

IGP1 = 4.1e-7 Torr.

Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.

 Monday, August 22, 2016, 16:01

IGP1 = 1.25e-6 torr

TGHT = 174A, 2.2V

TBHT = 118A, 1.4V

Lowering ramping rate to 0.2A/min and 0.1A/min for the TGHT and TBHT respectively for overnight ramping.

Laura Lambert wrote:

Wednesday, August 17, 2016, 17:30 Container coated with TaC using 'flushing technique', cleaned ionizer tube with acetone, so no coating inside ionizer tube Wrapped with 3 x Ta heat shields, incl center block Currently pumping down in evap2 Thursday, August 18, 2016, 10:14  HS water valves opened...leak detected  see attachment for photo from archives Vented and opened up. Anders performed leak check, nothing found. Replaced all seals with blue seals. Pumping down now  Thursday, August 18, 2016, 16:12 HS water valves opened...leak detected again  see attachment for photo of striptool Vented and opened up. working with Anders on finding leak...  Monday, August 22, 2016, 10:38 leaks FIXED! HS water valves opened, NO leaks detected! Tapped up manually to 70A Vacuum stable, IGP1 = 2.5e-6 Torr Initiating auto ramp for TGHT @ 0.2A/min to a max setpoint of 350A Initiating auto ramp for TBHT @ 0.1A/min to a max setpoint of 230A Once max setpoints achieved, will tap up manually to final desired temperature of 1900C  Monday, August 22, 2016, 14:58 TGHT = 115A, 1.3V TBHT = 89A, 0.97V IGP1 = 4.1e-7 Torr. Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.  Monday, August 22, 2016, 16:01 IGP1 = 1.25e-6 torr TGHT = 174A, 2.2V TBHT = 118A, 1.4V Lowering ramping rate to 0.2A/min and 0.1A/min for the TGHT and TBHT respectively for overnight ramping.

 Tuesday, August 23, 2016, 12:14

Initiate TGHT autoramping to 400A at 2A/min.  Vac 3.5e-7 Torr. 

 Tuesday, August 23, 2016, 14:48

TGHt tapped up to 420A/7.01V.  Local temp read at ~1900C.  Will sinter at this temp for a few hours before cooling down.

 Tuesday, August 23, 2016, 17:20

TGHT at been at 420A/7.01V for over 4 hours.  Vac at 4.8e-7 Torr.

Cooling TGHT and TBHT at 1A/min.

 Wednesday, August 24, 2016, 10:35

TGHT/TBHT at 0A.

Venting chamber.

Container looks good.

 Wednesday, September 07, 2016, 14:45

Container was previously coated with TaC solution and wrapped with 1-full length layer of Ta- heat shield around the fins.  

Chamber is being pumped down.  Vac at 5.6e-7 Torr before HS water valves were open; no leaks were detected. 

Sintering Temperature 1900C (Omega slope @ 0.98); expected TGHT ~765A/11.90V, TGHT max at 230A.

 Thursday, September 08, 2016, 18:14

At about 1600C, it was observed that the coating inside the tube seems to chip off (see attachment 1).

TGHT was ramped up to 745A/11.85V and TBHT to 230A/3.25V.  Temperature measured on OMEGA/Mikron = 1914C/1881C; both instruments slopes set at 0.98.

Will remain at this TGHT current over night

Vac at 3.0e-6 Torr and coming down.

Friday, September 09, 2016, 11:01 

Target has been heated at the stable temperature at 1914C (for OMEGA) and 1881C (for Mikron) with current at 745A/11.94V (see attachment 2) for almost 19 hours. 

No fluctuation in p/s current or temperature was observed.  The ramping up process is captured and can be view from the link below:

https://www.dropbox.com/sh/9lgtin54o17ds6j/AABn1-XjvK44mm74TjqTAmvta?dl=0

Pressure at 1.07e-6 Torr. 

Cooling down TGHT at 2A/min and TBHT at 1A/min. 

Continue to capture the cooling down process. 

 Friday, September 09, 2016, 15:17

 While the target container was cooling down, the chip-like particle began obvious (see attachment 3).  

Will inspect the container.. TGHT currently at 260A.

John Wong wrote:

Wednesday, September 07, 2016, 14:45 Container was previously coated with TaC solution and wrapped with 1-full length layer of Ta- heat shield around the fins.   Chamber is being pumped down.  Vac at 5.6e-7 Torr before HS water valves were open; no leaks were detected.  Sintering Temperature 1900C (Omega slope @ 0.98); expected TGHT ~765A/11.90V, TGHT max at 230A.  Thursday, September 08, 2016, 18:14 At about 1600C, it was observed that the coating inside the tube seems to chip off (see attachment 1). TGHT was ramped up to 745A/11.85V and TBHT to 230A/3.25V.  Temperature measured on OMEGA/Mikron = 1914C/1881C; both instruments slopes set at 0.98. Will remain at this TGHT current over night Vac at 3.0e-6 Torr and coming down. Friday, September 09, 2016, 11:01  Target has been heated at the stable temperature at 1914C (for OMEGA) and 1881C (for Mikron) with current at 745A/11.94V (see attachment 2) for almost 19 hours.  No fluctuation in p/s current or temperature was observed.  The ramping up process is captured and can be view from the link below: https://www.dropbox.com/sh/9lgtin54o17ds6j/AABn1-XjvK44mm74TjqTAmvta?dl=0 Pressure at 1.07e-6 Torr.  Cooling down TGHT at 2A/min and TBHT at 1A/min.  Continue to capture the cooling down process.   Friday, September 09, 2016, 15:17  While the target container was cooling down, the chip-like particle began obvious (see attachment 3).   Will inspect the container.. TGHT currently at 260A.

 Monday, September 12, 2016, 16:54

The TaC coating chipped off from the surface and didn't get sintered with the container.  (See attachment1). 

There are a few possible reasons why this happened:

1.  The coating was too think.  This may cause the TaC  layer to curl up while the heater was ramped up. 

2.  The coated material got brittle.  The container was flushed with TaC (probably a few weeks ago?) before it went through the sintering process.  Prolong exposure to air/light usually degrade the polymers viscoelasticity.

3.  TaC solution has got bad.  The particles can agglomerate over time and this can cause uneven surface.

4.  Combination of all... ???

Anyway, the chipped off TaC layer was gently scraped off with a stainless steel rod.  Then using kimwipes, i was able to remove most of the chipped off coating; it was not easy - especially trying to remove it from the inner tube.

Instead of "flushing" the tube with TaC, I decided to spray it with thin layer.  And using the air supply, I could quickly dry the coating and installed it back to the evaporator for 2nd Round sintering as we are approaching the deadline!

.                         

John Wong wrote:

John Wong wrote:  Wednesday, September 07, 2016, 14:45 Container was previously coated with TaC solution and wrapped with 1-full length layer of Ta- heat shield around the fins.   Chamber is being pumped down.  Vac at 5.6e-7 Torr before HS water valves were open; no leaks were detected.  Sintering Temperature 1900C (Omega slope @ 0.98); expected TGHT ~765A/11.90V, TGHT max at 230A.  Thursday, September 08, 2016, 18:14 At about 1600C, it was observed that the coating inside the tube seems to chip off (see attachment 1). TGHT was ramped up to 745A/11.85V and TBHT to 230A/3.25V.  Temperature measured on OMEGA/Mikron = 1914C/1881C; both instruments slopes set at 0.98. Will remain at this TGHT current over night Vac at 3.0e-6 Torr and coming down. Friday, September 09, 2016, 11:01  Target has been heated at the stable temperature at 1914C (for OMEGA) and 1881C (for Mikron) with current at 745A/11.94V (see attachment 2) for almost 19 hours.  No fluctuation in p/s current or temperature was observed.  The ramping up process is captured and can be view from the link below: https://www.dropbox.com/sh/9lgtin54o17ds6j/AABn1-XjvK44mm74TjqTAmvta?dl=0 Pressure at 1.07e-6 Torr.  Cooling down TGHT at 2A/min and TBHT at 1A/min.  Continue to capture the cooling down process.   Friday, September 09, 2016, 15:17  While the target container was cooling down, the chip-like particle began obvious (see attachment 3).   Will inspect the container.. TGHT currently at 260A.    Monday, September 12, 2016, 16:54 The TaC coating chipped off from the surface and didn't get sintered with the container.  (See attachment1).  There are a few possible reasons why this happened: 1.  The coating was too think.  This may cause the TaC  layer to curl up while the heater was ramped up.  2.  The coated material got brittle.  The container was flushed with TaC (probably a few weeks ago?) before it went through the sintering process.  Prolong exposure to air/light usually degrade the polymers viscoelasticity. 3.  TaC solution has got bad.  The particles can agglomerate over time and this can cause uneven surface. 4.  Combination of all... ??? Anyway, the chipped off TaC layer was gently scraped off with a stainless steel rod.  Then using kimwipes, i was able to remove most of the chipped off coating; it was not easy - especially trying to remove it from the inner tube. Instead of "flushing" the tube with TaC, I decided to spray it with thin layer.  And using the air supply, I could quickly dry the coating and installed it back to the evaporator for 2nd Round sintering as we are approaching the deadline! .

 Monday, September 12, 2016, 17:24

Chamber was pumped down to low 10e-6 Torr before HS water valves were open - no leaks detected.

TGHT/TBHT auto ramped at 2A/min to 600A/230A.

Will continue to monitor..

 Wednesday, September 14, 2016, 17:04

TGHT was stepped up to 700A and temp 1851C (OMEGA), 1930C(Mikron).  (see attachment 1).  The container was heated over night before it was cool down at 2A/min. 

Target container seems to properly sintered with TaC (see attachment 2); it will be used for SiC#35. 

 Wednesday, September 28, 2016, 17:08

Container coated with TaC using 'flushing technique' today, cleaned ionizer tube with acetone, no coating inside ionizer tube

Dried by blowing air into tube

Wrapped with 3 x Ta heat shields, incl center block - new method of each layer being one long single Ta foil covering entire container incl center block

Currently pumping down in evap2

 Thursday, September 29, 2016, 11:11

HS water valves opened

Tapped up to 35A

Waited ~45min, vacuum stable

IGP1 = 1.4e-6 Torr

Initiating auto ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively.

Max setpoints for TGHT = 350A and TBHT  = 230A

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

 Friday, September 30, 2016, 10:51

IGP1 = 7.8e-7 Torr

TGHT = 315A, 4.57V

TBHT = 174A, 2.8V

Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.

 Friday, September 30, 2016, 11:44

Changed OMEGA slope to 0.98

IGP1 = 1e-6 Torr

TGHT = 350A, 5.2V

TBHT = 201A, 3.4V

Increasing ramping rate of TBHT to 1.0A/min

OMEGA = 1625C / MIKRON = 1625C

 Friday, September 30, 2016, 15:45

IGP1 = 1.1e-6 Torr

TGHT = 430A, 6.79V

TBHT = 230A, 4.07V

OMEGA = 1903C

Will remain at max setpoints over weekend.

See attached link for raw data of manual tap up.

Also see attached photos of screenshots showing oval - not circular - tube of target container at two different temperatures...

 Monday, October 03, 2016, 13:28

IGP1 = 1.79e-7 Torr

TGHT = 430A, 6.87V

TBHT = 230A, 4.06V

OMEGA = 1892C

MIKRON = 1847C

Attached is a picture taken through the MIKRON, the slight oval shape appears to be a minor bend in the target container:

With the ionizer tube facing into the page, the bend appears to be in the center with both ends of the container bent slightly towards the page

This possible bend in the container gives the appearance of the oval shape through the camera while it is being heated, due to the angle of the camera

Remained at max setpoints over weekend.

Initiating auto-cool at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

 Tuesday, October 04, 2016, 13:40

Vented in air and opened up this morning.

Container done, TaC coating looks good.

Waiting further inspection...

 Tuesday, October 04, 2016, 14:48

Container placed on jig and inspected.

Approved to go ahead for use online by Anders and Friedhelm.

 Thursday, December 01, 2016, 16:06

Container coated with TaC using 'flushing technique' and let dry overnight.

Cleaned ionizer tube with acetone, no coating inside ionizer tube

Wrapped with 3 x Ta heat shields, incl center block

Currently pumping down in evap2

OMEGA slope = 0.98

 Friday, December 02, 2016, 11:24

Opened up HS water valves, no leaks detected.

Tapped up manually to 35A.

Waited ~25min, vacuum stable.

IGP1 = 1.65e-6 Torr

Initiating auto-ramp at 0.2A/min for the TGHT and 0.1A/min for the TBHT.

Max setpoints set for 350A and 230A for the TGHT and TBHT respectively.

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

 Monday, December 05, 2016, 09:38

TGHT = 350A, 5.38V

TBHT = 230A, 4.03V

OMEGA = 1550C

IGP1 = 3.2e-7 Torr

Tapping up to 1900C...

 Monday, December 05, 2016, 14:11

OMEGA = 1905C

TGHT = 475A, 7.63V

TBHT = 230A, 4.07V

IGP1 = 8.5e-7 Torr

 Tuesday, December 06, 2016, 08:41

TGHT = 475A, 7.76V

TBHT = 230A, 4.07V

IGP1 = 3.9e-7 Torr

Initiating auto-cool at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Wednesday, December 07, 2016, 08:46 

Evap2 was vented in air and opened up yesterday afternoon.

Container looks good, coating fully sintered.