John Wong wrote:

Friday, March 21, 2014, 16:09 Target container is loaded with 360 Discs of TiC.   Target length = 11.7cm.   Total green mass = 40.945g  Container is wrapped with 3 Ta-heat shields, and have been pumped down in the chamber.  For the sintering process:  TGHT ramp up to 820A, and TGHT to 300A at 0.1A/min.  Friday, March 21, 2014, 16:15 TGHT/TBHT were manually stepped up to 40A.   Vac stabilizes at 1.7e-6 Torr.   Initiate auto-ramping...

 Wednesday, March 26, 2014, 11:05

TBHT reached max desired current of 300A

IGP1 = 1.4e-6 Torr

TGHT = 543A

Increasing TGHT auto-ramp to 2.0A/min

Thursday, March 27, 2014, 17:38

TEST #1

WC slurry was prepared in non-aqueous environment (see lab book for procedures).  The solution was dripped on two Ta plates (3.1cm2) and let dry. 

Another Ta plate (3.1 cm2) was sprayed with TaC coating (for comparison).

All 3 coated Ta plates are put in a target boat and the boat is wrapped with 3 layers of Ta-heat shields.

HS water valves open; no leaks detected.

TGHT will be ramped up to 700A at 2.0A/min.

RGA is running and gases are being monitored.  See link:

https://www.dropbox.com/sh/625xl7zgepbybmu/GQJTlMo-5a

 Friday, March 28, 2014, 09:13

TGHT reached to 700A and samples were heated up over night. 

Cooling down Evap at 4A/min. 

 Tuesday, April 01, 2014, 17:37

Previous samples, namely WC#1, #2, TC#1 were fully sinterred.  See above link for photos.

TEST#2

Samples WC#3, #4, #5 are sprayed coated with WC solution.  Grains were pre-treated at 400RPM.

These 3 new samples are loaded in a boat, wrapped with 3 layers of Ta-heat shields.

Chamber is pumped down; no water leaks are detected.

TGHT will be ramped up to 700A at 2.0A/min

RGA is running.

Samples were analyzed with SEM/EDX.  The results are inconclusive because W and Ta peaks are very close together.  And WC coated layer may be even too thin to analyze. 

 Monday, April 14, 2014, 16:32

Test#3:  Coated WC on Endcap.  Total mass WC ~350mg.

Sintered at 500A/9.5V; measure temperature on actual sample surface ~1700C.  Sample heated >24hr.

Cooling down TGHT at 2A/min.  IG currently at 3.1e-7 Torr.

Purpose: Sinter one sample of each of TiC, VC, Cr3C2, ZrC, NbC, Mo2C, TaC, and WC on 5x10 mm tantalum foil to see if the samples are usable for SEM.

Samples were prepared using a solution of PEG (2.56 g), PVB (2.45 g), paraffin oil (1.12 g), MEK (15 mL), and EtOH (23 mL). Slurries made using 0.0013 mol of each carbide with ~230 uL of the solution. Applied via paintbrush onto 5x10 mm tantalum foil. 

The samples were placed directly on the target boat, no graphite layer between. We will check to see if the tantalum foil fuses to the boat or not.

Currently (May 29th), the chamber is still pumping down. John and I will continue the procedure tomorrow.

 Pressure down to 7.1e-7 Torr. Water valve to heat shield was opened; pressure remained stable. 

Current turned up to 40 A for now.  Will increase at 2 A/min up to 500 A over the weekend, then on Monday we will turn it up to 600 A and check the temperature. 

Auto-ramp started. Max current = 500 A, voltage = 11.05 V. Current is being increased at 2 A/min. In the first 20 minutes, the pressure went up to about 10E-6 T, but has slowly decreased since then. Everything looks ok. The system will be left until Monday morning (June 9th). 

Manually changed current from 500 to 615 A, monitoring the temperature. Temperature went from 1657 C up to 1838 C. Pressure increased up to 7.2e-7 T. Samples should be left for about 4 hours (615 A started just before 13:00), then the goal is to ramp current back to zero.

 Target boat is now being cooled at 1 A/min from the starting point (616 A) down to 0 A. 

 Friday, June 13, 2014, 14:53

Container is filled with 400 discs of Ta foils; target length = 5.2cm;

Total mass ( Ta foils + wire) = 45.92g

No Ta foil heat shield.

No caps inserted.

Chamber pumped down this morning.

HS cooling water valves opened, no leaks detected.

IG @ 5.8e-6 Torr.

TGHT max = 580A

TBHT max = 230A

Ramping rate 0.2A/min.

 Monday, June 16, 2014, 11:46

TGHT and TBHT reached their respective 580A and 230A over the weekend.

IGP1 currently at 3.2e-7 Torr.

Internal temp [measured using mikron, right side of EVAP2, pointed at discs inside] = 1375C

Laura Lambert wrote:

Friday, June 13, 2014, 14:53 Container is filled with 400 discs of Ta foils. No Ta foil heat shield. No caps inserted. Chamber pumped down this morning. HS cooling water valves opened, no leaks detected. IG @ 5.8e-6 Torr. TGHT max = 580A TBHT max = 230A Ramping rate 0.2A/min.  Monday, June 16, 2014, 11:46 TGHT and TBHT reached their respective 580A and 230A over the weekend. IGP1 currently at 3.2e-7 Torr. Internal temp [measured using mikron, right side of EVAP2, pointed at discs inside] = 1375C

 Monday, June 16, 2014, 17:21

Further stepping up TGHT to 650A.

Temperature measured on target discs = 1542C. Vac @ 3.28e-7 Torr.

Initiate cooling down process; 2A/min for TGHT; 1A/min for TBHT

 Friday, June 20, 2014, 11:14

Made from batch's: oct 23/2013, oct 31/2013 and june 2012

Total number of foils: 515 discs

Total mass of materials [incl graphite foils]: 64.7224g

Total length packed: 17.8cm

Container is wrapped with 3x Ta-heat shields.

Currently being pumped down.

 Friday, June 20, 2014, 14:56

HS cooling water valves opened, no leaks detected.

IGP1 = 6.2e-6 Torr

TGHT max = 820A/ 17V

TBHT max = 300A/ 5V

Stepping up manually to 40A

 Friday, June 20, 2014, 16:04

IGP1 = 8e-6 Torr

Slowly stepped up to 35A manually.

Vacuum has stabilized.

Initiating auto-ramp at 0.1A/min

Laura Lambert wrote:

Friday, June 20, 2014, 11:14 Total number of foils: 515 discs Total mass of materials [incl graphite foils]: 64.7224g Total length packed: 17.8cm Container is wrapped with 3x Ta-heat shields. Currently being pumped down.  Friday, June 20, 2014, 14:56 HS cooling water valves opened, no leaks detected. IGP1 = 6.2e-6 Torr TGHT max = 820A/ 17V TBHT max = 300A/ 5V Stepping up manually to 40A  Friday, June 20, 2014, 16:04 IGP1 = 8e-6 Torr Slowly stepped up to 35A manually. Vacuum has stabilized. Initiating auto-ramp at 0.1A/min

 Friday, June 20, 2014, 16:16

Changing the heating current... 

From the previous SiC targets, TGHT was ramped up to 800A and yellow crystals were found; the end caps and target legs were also found broken (see my iPad).  This might be too hot for the Ta-boat to handle the sintering process. 

For this process,

TGHT will ramp up to 600A and TBHT to 230A over the weekend. 

Then, the temperature will be measured.  The sintering temperature of SiC is ~1800 - 2000C. 

John Wong wrote:

Laura Lambert wrote:  Friday, June 20, 2014, 11:14 Total number of foils: 515 discs Total mass of materials [incl graphite foils]: 64.7224g Total length packed: 17.8cm Container is wrapped with 3x Ta-heat shields. Currently being pumped down.  Friday, June 20, 2014, 14:56 HS cooling water valves opened, no leaks detected. IGP1 = 6.2e-6 Torr TGHT max = 820A/ 17V TBHT max = 300A/ 5V Stepping up manually to 40A  Friday, June 20, 2014, 16:04 IGP1 = 8e-6 Torr Slowly stepped up to 35A manually. Vacuum has stabilized. Initiating auto-ramp at 0.1A/min    Friday, June 20, 2014, 16:16 Changing the heating current...  From the previous SiC targets, TGHT was ramped up to 800A and yellow crystals were found; the end caps and target legs were also found broken (see my iPad).  This might be too hot for the Ta-boat to handle the sintering process.  For this process, TGHT will ramp up to 600A and TBHT to 230A over the weekend.  Then, the temperature will be measured.  The sintering temperature of SiC is ~1800 - 2000C.

 Monday, June 23, 2014, 09:45

IGP1 = 5e-6 Torr

TGHT and TBHT are at ~200A

Increasing ramping rate to 0.2A/min

 Monday, June 23, 2014, 11:19

IGP1 = 6.9e-6 Torr

Increasing ramping rate to 2.0A/min

Monday, June 23, 2014, 12:09

JW:  Pressure went up too fast... lower the TGHT ramping up rate to 1A/min.

 Tuesday, June 24, 2014, 16:06

Increasing current with respect to temperature: See attached table

Laura Lambert wrote:

John Wong wrote: Laura Lambert wrote:  Friday, June 20, 2014, 11:14 Total number of foils: 515 discs Total mass of materials [incl graphite foils]: 64.7224g Total length packed: 17.8cm Container is wrapped with 3x Ta-heat shields. Currently being pumped down.  Friday, June 20, 2014, 14:56 HS cooling water valves opened, no leaks detected. IGP1 = 6.2e-6 Torr TGHT max = 820A/ 17V TBHT max = 300A/ 5V Stepping up manually to 40A  Friday, June 20, 2014, 16:04 IGP1 = 8e-6 Torr Slowly stepped up to 35A manually. Vacuum has stabilized. Initiating auto-ramp at 0.1A/min    Friday, June 20, 2014, 16:16 Changing the heating current...  From the previous SiC targets, TGHT was ramped up to 800A and yellow crystals were found; the end caps and target legs were also found broken (see my iPad).  This might be too hot for the Ta-boat to handle the sintering process.  For this process, TGHT will ramp up to 600A and TBHT to 230A over the weekend.  Then, the temperature will be measured.  The sintering temperature of SiC is ~1800 - 2000C.     Monday, June 23, 2014, 09:45 IGP1 = 5e-6 Torr TGHT and TBHT are at ~200A Increasing ramping rate to 0.2A/min  Monday, June 23, 2014, 11:19 IGP1 = 6.9e-6 Torr Increasing ramping rate to 2.0A/min Monday, June 23, 2014, 12:09 JW:  Pressure went up too fast... lower the TGHT ramping up rate to 1A/min.  Tuesday, June 24, 2014, 16:06 Increasing current with respect to temperature: See attached table

 Tuesday, June 24, 2014, 23:44

Target has been heated at 600A.  Local temperature measured on the right leg = 1814C. 

RGA/ striptool/temperature data can be found on this link: 

https://www.dropbox.com/sh/69memvh6fthodoz/AABZiSKAR9njhbqO4sBATVbla

Something interesting was observed about the out gassing of this target - the right window was coated when the temperature rose above 1500C (on the right end, could be hotter inside?) - see attachment.

I suspect this is Si vapour deposited on the window when the target heater got closed to the sintering temperature for SiC (1800 - 2000C).  

Once the chamber is vented, the coated window will be inspected and analyzed.  More details later...  

Initiate auto-cooling (slow cool down)  TGHT 1A/min; TBHT 0.5/min.  Chamber should be able for venting tomorrow afternoon.  

Wednesday, July 23, 2014, 15:07

Target container is coated with TaC.  No Ta-heat shields are used.

TGHT will be ramped up to 580A at 0.2A/min.

TBHT will be ramped up to 230A at 0.2A/min.

Chamber is currently being pumped down

 Wednesday, July 23, 2014, 17:40

Vacuum came down to mid 10-6 Torr.

Stepped up TGHT and TBHT to 30A - IG1 @ 1.4e-5 Torr.

Initiated auto-ramping.

 Thursday, July 24, 2014, 17:19

TGHT and TBHT have reached to 100A, and vacuum is coming down to 1.4e-6 Torr.

Increase ramping rate, TGHT to 1A/min, TBHT 0.5A/min.

 Friday, July 25, 2014, 11:26

Target container temperature reaches ~1550C at 580A on TGHT and 230A TBHT, and it has been heated for ~10 hrs.

Auto-cooling initiated at 2A/min.

 Monday, July 28, 2014, 14:41

Total number of foils: 445 discs

Total mass of materials [incl graphite foils]: 49.027 g

Total length packed: 11.2 cm

Container has no Ta heat shields.

Currently being pumped down.

Laura Lambert wrote:

Monday, July 28, 2014, 14:41 Total number of foils: 445 discs Total mass of materials [incl graphite foils]: 49.027 g Total length packed: 11.2 cm Container has no Ta heat shields. Currently being pumped down.

 Tuesday, July 29, 2014, 11:19

Chamber was pumped down overnight to ~5.5e-7 torr.

HS water valve opened; no leaks were detected.

Stepped up TGHT/TBHT to 40A. IG went up 8e-6 Torr and stabilized. 

Initiated auto-ramping TGHT @ 580A, TBHt @ 230A at 0.2A/min

The maximum current of 580A was reached at 9:15.

TGHT:RDCUR 578 A

TGHT:RDVOL 9.87 V

IGP1:RDVAC 3.8e-6

The temperature was measured with the Minolta 2-color pyrometer:

from the side - inside target container : ~1200 deg C

from the front trough hole in the heat shield : ~1800 deg C

Target was conditioned for 4 hours at 580A.

Initiating ramp-down sequence @ 2A/min

 Tuesday, August 05, 2014, 12:02

The target container end caps were coated with TaC spray and let dry.

The caps are inserted in the target boat vertically, wrapped in graphite foil with 3 x Ta-heat shield. [see attached photo]

The chamber is currently being pumped down.

Laura Lambert wrote:

Tuesday, August 05, 2014, 12:02 The target container end caps were coated with TaC spray and let dry. The caps are inserted in the target boat vertically, wrapped in graphite foil with 3 x Ta-heat shield. [see attached photo] The chamber is currently being pumped down.

 Tuesday, August 05, 2014, 17:19

HS water valve opened; no leaks detected. 

Pressure @ 2.5e-6 Torr.

Ramping up TGHT to 580A @ 1A/min.