Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater
We always used to spot weld the T/C to the bottom of the strip. A big challenge is to avoid pickup of voltage from the strip (which is resistively heated) by the T/C – this can lead to false temperature indications, sometimes huge! I strongly recommend verification of the temperature by some other means, either by running an internal or external standard powder, by optical pyrometry, or something like that. If you run your heater using A/C rather than D/C power that will help reduce this effect. Andrew --- Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Mailing Address: Oak Ridge National Laboratory P.O. Box 2008 Building 8600, MS 6475 Oak Ridge, TN, 37831 Cell: (865) 235-4981 Email: payza...@ornl.gov<mailto:payza...@ornl.gov> https://www.ornl.gov/staff-profile/e-andrew-payzant From: "Mibeck, Blaise" Date: Thursday, July 25, 2019 at 4:23 PM To: Julian Richard Tolchard , "Payzant, Andrew" Cc: Rietveld list Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Been a long day. I did have a new platinum ribbon heater and it working well! I would like to know this: how is the thermocouple attached to these ribbon heaters? (From Edmond- Buehler) Thanks for any more advice. I really appreciate the help! Get Outlook for Android<https://aka.ms/ghei36> From: Julian Richard Tolchard Sent: Thursday, July 25, 2019 10:40:26 AM To: Payzant, Andrew ; Mibeck, Blaise Cc: rietveld_l@ill.fr Subject: RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Andrew, I agree completely. Pt does definitely have its problems, but it's hard to get radiant heaters that go so high in temperature. My feeling is that if you want to pursue HT-XRD in any serious fashion you need to accept the idea that Pt / Ta strips and thermocouples etc are "consumables" and live with the associated cost. I know this is difficult for a lot of university labs, but once you adopt that mindset you can do much more interesting experiments. Jools From: Payzant, Andrew Sent: torsdag 25. juli 2019 17.08 To: Julian Richard Tolchard ; Mibeck, Blaise Cc: rietveld_l@ill.fr Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Jools, You are right. “Lab grade” bottled N2 may have enough residual oxygen to cause problems, plus it is hard to purge the chamber properly to get the pO2 low enough to avoid issues. But an H2/N2 mix might not be suitable, especially if it destabilizes his sample. Here are some other ideas: 1. I used to flow high purity N2 through a gettering furnace in series with the HTXRD chamber, and that, coupled with multiple purges of the chamber prior to starting the experiment, worked pretty well. 2. I have in the past used a Bühler HT furnace that had a secondary “surround heater” option. I had some success putting a gettering wire across these leads and running it at a higher temperature than the heater strip in order to remove traces of oxygen from the chamber. This has the advantage that as you heat up the walls of the chamber and release adsorbed oxygen it goes to the getter rather than the strip. It can be a bit tricky ensuring that the getter is hotter than the strip across the range of temperatures that you run. However, I fully agree with you that a platinum foil is probably a better option for Blaise’s experiment. If he has one handy. There are some caveats regarding platinum though. It is generally more expensive. It is readily attacked by silicon, iron, and other elements. You can get recrystallization and/or rapid grain growth at high temperatures, which dramatically changes the diffraction pattern from the strip during a HTXRD experiment. The relatively high CTE means that the strip height will change as the temperature increases, which will cause large peak shifts unless you are using parallel beam optics and even then will cause intensity variations at the lower 2thetas. If you work at a US government lab, platinum is a precious metal and there is some paperwork required every time you change heater strips. Also, if your sample melts or sinters, you may have some “fun” getting the platinum clean. Andrew * Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Neutron Sciences Directorate Mailing address: Oak Ridge National Laboratory Dr. E. Andrew Payzant P.O. Box 2008 Bldg. 8600, MS 6475 Oak Ridge, TN 37831 cell: (865) 235-4981 email: payza...@ornl.gov<mailto:payza...@ornl.gov> https://www.ornl.gov/staff-profile/e-andrew-payzant ** From: Julian Richard Tolchard mailto:julianrichard.tolch...@sintef.no>> Date: Thursday, July 25, 2019 at 10:47 AM To: "Mibeck, Blaise&
Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater
I agree with Tim. HT stages such as Anton Paar’s XRK900 provide excellent temperature control and stability across a range of atmospheres. One advantage that strip heaters still have is in rapid heating and cooling. A --- Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Mailing Address: Oak Ridge National Laboratory P.O. Box 2008 Building 8600, MS 6475 Oak Ridge, TN, 37831 Cell: (865) 235-4981 Email: payza...@ornl.gov<mailto:payza...@ornl.gov> https://www.ornl.gov/staff-profile/e-andrew-payzant From: Timothy Hyde Date: Friday, July 26, 2019 at 6:07 AM To: "Mibeck, Blaise" , Julian Richard Tolchard , "Payzant, Andrew" Cc: Rietveld list Subject: RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Blaise, Andrew, below correctly summarises the issues with strip heaters, and as Julian mentions, even if you can get them working satisfactorily they are essentially rather expensive consumables. While for you not an immediate solution, for the reasons outlined by Andrew and Julian, we moved to alternative in situ heating technologies. Should you or anyone be considering replacing a ribbon beater, please look into such alternatives from commercial suppliers such as Anton Paar, which have generally eliminated many of the issues that we are discussing below. Tim From: rietveld_l-requ...@ill.fr On Behalf Of Mibeck, Blaise Sent: 25 July 2019 21:23 To: Julian Richard Tolchard ; Payzant, Andrew Cc: rietveld_l@ill.fr Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Been a long day. I did have a new platinum ribbon heater and it working well! I would like to know this: how is the thermocouple attached to these ribbon heaters? (From Edmond- Buehler) Thanks for any more advice. I really appreciate the help! Get Outlook for Android<https://aka.ms/ghei36> From: Julian Richard Tolchard mailto:julianrichard.tolch...@sintef.no>> Sent: Thursday, July 25, 2019 10:40:26 AM To: Payzant, Andrew mailto:payza...@ornl.gov>>; Mibeck, Blaise mailto:bmib...@undeerc.org>> Cc: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr> mailto:rietveld_l@ill.fr>> Subject: RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Andrew, I agree completely. Pt does definitely have its problems, but it's hard to get radiant heaters that go so high in temperature. My feeling is that if you want to pursue HT-XRD in any serious fashion you need to accept the idea that Pt / Ta strips and thermocouples etc are "consumables" and live with the associated cost. I know this is difficult for a lot of university labs, but once you adopt that mindset you can do much more interesting experiments. Jools From: Payzant, Andrew mailto:payza...@ornl.gov>> Sent: torsdag 25. juli 2019 17.08 To: Julian Richard Tolchard mailto:julianrichard.tolch...@sintef.no>>; Mibeck, Blaise mailto:bmib...@undeerc.org>> Cc: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr> Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Jools, You are right. “Lab grade” bottled N2 may have enough residual oxygen to cause problems, plus it is hard to purge the chamber properly to get the pO2 low enough to avoid issues. But an H2/N2 mix might not be suitable, especially if it destabilizes his sample. Here are some other ideas: 1. I used to flow high purity N2 through a gettering furnace in series with the HTXRD chamber, and that, coupled with multiple purges of the chamber prior to starting the experiment, worked pretty well. 2. I have in the past used a Bühler HT furnace that had a secondary “surround heater” option. I had some success putting a gettering wire across these leads and running it at a higher temperature than the heater strip in order to remove traces of oxygen from the chamber. This has the advantage that as you heat up the walls of the chamber and release adsorbed oxygen it goes to the getter rather than the strip. It can be a bit tricky ensuring that the getter is hotter than the strip across the range of temperatures that you run. However, I fully agree with you that a platinum foil is probably a better option for Blaise’s experiment. If he has one handy. There are some caveats regarding platinum though. It is generally more expensive. It is readily attacked by silicon, iron, and other elements. You can get recrystallization and/or rapid grain growth at high temperatures, which dramatically changes the diffraction pattern from the strip during a HTXRD experiment. The relatively high CTE means that the strip height will change as the temperature increases, which will cause large peak shifts unless you are using parallel beam optics and even then will cause intensity variations at the lower 2thetas. If you work
RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater
Blaise, Andrew, below correctly summarises the issues with strip heaters, and as Julian mentions, even if you can get them working satisfactorily they are essentially rather expensive consumables. While for you not an immediate solution, for the reasons outlined by Andrew and Julian, we moved to alternative in situ heating technologies. Should you or anyone be considering replacing a ribbon beater, please look into such alternatives from commercial suppliers such as Anton Paar, which have generally eliminated many of the issues that we are discussing below. Tim From: rietveld_l-requ...@ill.fr On Behalf Of Mibeck, Blaise Sent: 25 July 2019 21:23 To: Julian Richard Tolchard ; Payzant, Andrew Cc: rietveld_l@ill.fr Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Been a long day. I did have a new platinum ribbon heater and it working well! I would like to know this: how is the thermocouple attached to these ribbon heaters? (From Edmond- Buehler) Thanks for any more advice. I really appreciate the help! Get Outlook for Android<https://aka.ms/ghei36> From: Julian Richard Tolchard mailto:julianrichard.tolch...@sintef.no>> Sent: Thursday, July 25, 2019 10:40:26 AM To: Payzant, Andrew mailto:payza...@ornl.gov>>; Mibeck, Blaise mailto:bmib...@undeerc.org>> Cc: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr> mailto:rietveld_l@ill.fr>> Subject: RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Andrew, I agree completely. Pt does definitely have its problems, but it's hard to get radiant heaters that go so high in temperature. My feeling is that if you want to pursue HT-XRD in any serious fashion you need to accept the idea that Pt / Ta strips and thermocouples etc are "consumables" and live with the associated cost. I know this is difficult for a lot of university labs, but once you adopt that mindset you can do much more interesting experiments. Jools From: Payzant, Andrew mailto:payza...@ornl.gov>> Sent: torsdag 25. juli 2019 17.08 To: Julian Richard Tolchard mailto:julianrichard.tolch...@sintef.no>>; Mibeck, Blaise mailto:bmib...@undeerc.org>> Cc: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr> Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Jools, You are right. “Lab grade” bottled N2 may have enough residual oxygen to cause problems, plus it is hard to purge the chamber properly to get the pO2 low enough to avoid issues. But an H2/N2 mix might not be suitable, especially if it destabilizes his sample. Here are some other ideas: 1. I used to flow high purity N2 through a gettering furnace in series with the HTXRD chamber, and that, coupled with multiple purges of the chamber prior to starting the experiment, worked pretty well. 2. I have in the past used a Bühler HT furnace that had a secondary “surround heater” option. I had some success putting a gettering wire across these leads and running it at a higher temperature than the heater strip in order to remove traces of oxygen from the chamber. This has the advantage that as you heat up the walls of the chamber and release adsorbed oxygen it goes to the getter rather than the strip. It can be a bit tricky ensuring that the getter is hotter than the strip across the range of temperatures that you run. However, I fully agree with you that a platinum foil is probably a better option for Blaise’s experiment. If he has one handy. There are some caveats regarding platinum though. It is generally more expensive. It is readily attacked by silicon, iron, and other elements. You can get recrystallization and/or rapid grain growth at high temperatures, which dramatically changes the diffraction pattern from the strip during a HTXRD experiment. The relatively high CTE means that the strip height will change as the temperature increases, which will cause large peak shifts unless you are using parallel beam optics and even then will cause intensity variations at the lower 2thetas. If you work at a US government lab, platinum is a precious metal and there is some paperwork required every time you change heater strips. Also, if your sample melts or sinters, you may have some “fun” getting the platinum clean. Andrew * Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Neutron Sciences Directorate Mailing address: Oak Ridge National Laboratory Dr. E. Andrew Payzant P.O. Box 2008 Bldg. 8600, MS 6475 Oak Ridge, TN 37831 cell: (865) 235-4981 email: payza...@ornl.gov<mailto:payza...@ornl.gov> https://www.ornl.gov/staff-profile/e-andrew-payzant ** From: Julian Richard Tolchard mailto:julianrichard.tolch...@sintef.no>> Date: Thursday, July 25, 2019 at 10:47 AM To: "Mibeck, Blaise"
Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater
Been a long day. I did have a new platinum ribbon heater and it working well! I would like to know this: how is the thermocouple attached to these ribbon heaters? (From Edmond- Buehler) Thanks for any more advice. I really appreciate the help! Get Outlook for Android<https://aka.ms/ghei36> From: Julian Richard Tolchard Sent: Thursday, July 25, 2019 10:40:26 AM To: Payzant, Andrew ; Mibeck, Blaise Cc: rietveld_l@ill.fr Subject: RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Andrew, I agree completely. Pt does definitely have its problems, but it's hard to get radiant heaters that go so high in temperature. My feeling is that if you want to pursue HT-XRD in any serious fashion you need to accept the idea that Pt / Ta strips and thermocouples etc are "consumables" and live with the associated cost. I know this is difficult for a lot of university labs, but once you adopt that mindset you can do much more interesting experiments. Jools From: Payzant, Andrew Sent: torsdag 25. juli 2019 17.08 To: Julian Richard Tolchard ; Mibeck, Blaise Cc: rietveld_l@ill.fr Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Jools, You are right. “Lab grade” bottled N2 may have enough residual oxygen to cause problems, plus it is hard to purge the chamber properly to get the pO2 low enough to avoid issues. But an H2/N2 mix might not be suitable, especially if it destabilizes his sample. Here are some other ideas: 1. I used to flow high purity N2 through a gettering furnace in series with the HTXRD chamber, and that, coupled with multiple purges of the chamber prior to starting the experiment, worked pretty well. 2. I have in the past used a Bühler HT furnace that had a secondary “surround heater” option. I had some success putting a gettering wire across these leads and running it at a higher temperature than the heater strip in order to remove traces of oxygen from the chamber. This has the advantage that as you heat up the walls of the chamber and release adsorbed oxygen it goes to the getter rather than the strip. It can be a bit tricky ensuring that the getter is hotter than the strip across the range of temperatures that you run. However, I fully agree with you that a platinum foil is probably a better option for Blaise’s experiment. If he has one handy. There are some caveats regarding platinum though. It is generally more expensive. It is readily attacked by silicon, iron, and other elements. You can get recrystallization and/or rapid grain growth at high temperatures, which dramatically changes the diffraction pattern from the strip during a HTXRD experiment. The relatively high CTE means that the strip height will change as the temperature increases, which will cause large peak shifts unless you are using parallel beam optics and even then will cause intensity variations at the lower 2thetas. If you work at a US government lab, platinum is a precious metal and there is some paperwork required every time you change heater strips. Also, if your sample melts or sinters, you may have some “fun” getting the platinum clean. Andrew * Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Neutron Sciences Directorate Mailing address: Oak Ridge National Laboratory Dr. E. Andrew Payzant P.O. Box 2008 Bldg. 8600, MS 6475 Oak Ridge, TN 37831 cell: (865) 235-4981 email: payza...@ornl.gov<mailto:payza...@ornl.gov> https://www.ornl.gov/staff-profile/e-andrew-payzant ** From: Julian Richard Tolchard mailto:julianrichard.tolch...@sintef.no>> Date: Thursday, July 25, 2019 at 10:47 AM To: "Mibeck, Blaise" mailto:bmib...@undeerc.org>>, Andrew Payzant mailto:payza...@ornl.gov>> Cc: Rietveld list mailto:rietveld_l@ill.fr>> Subject: RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Actually, i wouldn't recommend that either My experience with the Ta heaters is that they react with even the smallest amount of oxygen, and bottled N2 has more than enough to kill a Ta strip. The best result we had was with a H2/N2 mix, but that still failed (probably reaction with the sample). Personally I think the only reliable way to use them is with a high vacuum system (turbo pump), and with relatively inert samples. Ultimately you are better off getting a Pt strip instead. Jools From: rietveld_l-requ...@ill.fr<mailto:rietveld_l-requ...@ill.fr> mailto:rietveld_l-requ...@ill.fr>> On Behalf Of Mibeck, Blaise Sent: torsdag 25. juli 2019 16.27 To: Payzant, Andrew mailto:payza...@ornl.gov>> Cc: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr> Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Thank you -- I will try nitrogen then! __
RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater
Andrew, I agree completely. Pt does definitely have its problems, but it's hard to get radiant heaters that go so high in temperature. My feeling is that if you want to pursue HT-XRD in any serious fashion you need to accept the idea that Pt / Ta strips and thermocouples etc are "consumables" and live with the associated cost. I know this is difficult for a lot of university labs, but once you adopt that mindset you can do much more interesting experiments. Jools From: Payzant, Andrew Sent: torsdag 25. juli 2019 17.08 To: Julian Richard Tolchard ; Mibeck, Blaise Cc: rietveld_l@ill.fr Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Jools, You are right. “Lab grade” bottled N2 may have enough residual oxygen to cause problems, plus it is hard to purge the chamber properly to get the pO2 low enough to avoid issues. But an H2/N2 mix might not be suitable, especially if it destabilizes his sample. Here are some other ideas: 1. I used to flow high purity N2 through a gettering furnace in series with the HTXRD chamber, and that, coupled with multiple purges of the chamber prior to starting the experiment, worked pretty well. 2. I have in the past used a Bühler HT furnace that had a secondary “surround heater” option. I had some success putting a gettering wire across these leads and running it at a higher temperature than the heater strip in order to remove traces of oxygen from the chamber. This has the advantage that as you heat up the walls of the chamber and release adsorbed oxygen it goes to the getter rather than the strip. It can be a bit tricky ensuring that the getter is hotter than the strip across the range of temperatures that you run. However, I fully agree with you that a platinum foil is probably a better option for Blaise’s experiment. If he has one handy. There are some caveats regarding platinum though. It is generally more expensive. It is readily attacked by silicon, iron, and other elements. You can get recrystallization and/or rapid grain growth at high temperatures, which dramatically changes the diffraction pattern from the strip during a HTXRD experiment. The relatively high CTE means that the strip height will change as the temperature increases, which will cause large peak shifts unless you are using parallel beam optics and even then will cause intensity variations at the lower 2thetas. If you work at a US government lab, platinum is a precious metal and there is some paperwork required every time you change heater strips. Also, if your sample melts or sinters, you may have some “fun” getting the platinum clean. Andrew * Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Neutron Sciences Directorate Mailing address: Oak Ridge National Laboratory Dr. E. Andrew Payzant P.O. Box 2008 Bldg. 8600, MS 6475 Oak Ridge, TN 37831 cell: (865) 235-4981 email: payza...@ornl.gov<mailto:payza...@ornl.gov> https://www.ornl.gov/staff-profile/e-andrew-payzant ** From: Julian Richard Tolchard mailto:julianrichard.tolch...@sintef.no>> Date: Thursday, July 25, 2019 at 10:47 AM To: "Mibeck, Blaise" mailto:bmib...@undeerc.org>>, Andrew Payzant mailto:payza...@ornl.gov>> Cc: Rietveld list mailto:rietveld_l@ill.fr>> Subject: RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Actually, i wouldn't recommend that either My experience with the Ta heaters is that they react with even the smallest amount of oxygen, and bottled N2 has more than enough to kill a Ta strip. The best result we had was with a H2/N2 mix, but that still failed (probably reaction with the sample). Personally I think the only reliable way to use them is with a high vacuum system (turbo pump), and with relatively inert samples. Ultimately you are better off getting a Pt strip instead. Jools From: rietveld_l-requ...@ill.fr<mailto:rietveld_l-requ...@ill.fr> mailto:rietveld_l-requ...@ill.fr>> On Behalf Of Mibeck, Blaise Sent: torsdag 25. juli 2019 16.27 To: Payzant, Andrew mailto:payza...@ornl.gov>> Cc: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr> Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Thank you -- I will try nitrogen then! From: Payzant, Andrew mailto:payza...@ornl.gov>> Sent: Thursday, July 25, 2019 9:08 AM To: Mibeck, Blaise mailto:bmib...@undeerc.org>> Cc: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr> mailto:rietveld_l@ill.fr>> Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater STOP!!! The tantalum foil should not be used for high temperature in air. Above a few hundred degrees Celsius it will oxidize rapidly and disintegrate. I accidently learned this the hard way many years ago!
Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater
Jools, You are right. “Lab grade” bottled N2 may have enough residual oxygen to cause problems, plus it is hard to purge the chamber properly to get the pO2 low enough to avoid issues. But an H2/N2 mix might not be suitable, especially if it destabilizes his sample. Here are some other ideas: 1. I used to flow high purity N2 through a gettering furnace in series with the HTXRD chamber, and that, coupled with multiple purges of the chamber prior to starting the experiment, worked pretty well. 2. I have in the past used a Bühler HT furnace that had a secondary “surround heater” option. I had some success putting a gettering wire across these leads and running it at a higher temperature than the heater strip in order to remove traces of oxygen from the chamber. This has the advantage that as you heat up the walls of the chamber and release adsorbed oxygen it goes to the getter rather than the strip. It can be a bit tricky ensuring that the getter is hotter than the strip across the range of temperatures that you run. However, I fully agree with you that a platinum foil is probably a better option for Blaise’s experiment. If he has one handy. There are some caveats regarding platinum though. It is generally more expensive. It is readily attacked by silicon, iron, and other elements. You can get recrystallization and/or rapid grain growth at high temperatures, which dramatically changes the diffraction pattern from the strip during a HTXRD experiment. The relatively high CTE means that the strip height will change as the temperature increases, which will cause large peak shifts unless you are using parallel beam optics and even then will cause intensity variations at the lower 2thetas. If you work at a US government lab, platinum is a precious metal and there is some paperwork required every time you change heater strips. Also, if your sample melts or sinters, you may have some “fun” getting the platinum clean. Andrew * Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Neutron Sciences Directorate Mailing address: Oak Ridge National Laboratory Dr. E. Andrew Payzant P.O. Box 2008 Bldg. 8600, MS 6475 Oak Ridge, TN 37831 cell: (865) 235-4981 email: payza...@ornl.gov https://www.ornl.gov/staff-profile/e-andrew-payzant ** From: Julian Richard Tolchard Date: Thursday, July 25, 2019 at 10:47 AM To: "Mibeck, Blaise" , Andrew Payzant Cc: Rietveld list Subject: RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Actually, i wouldn't recommend that either My experience with the Ta heaters is that they react with even the smallest amount of oxygen, and bottled N2 has more than enough to kill a Ta strip. The best result we had was with a H2/N2 mix, but that still failed (probably reaction with the sample). Personally I think the only reliable way to use them is with a high vacuum system (turbo pump), and with relatively inert samples. Ultimately you are better off getting a Pt strip instead. Jools From: rietveld_l-requ...@ill.fr On Behalf Of Mibeck, Blaise Sent: torsdag 25. juli 2019 16.27 To: Payzant, Andrew Cc: rietveld_l@ill.fr Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Thank you -- I will try nitrogen then! From: Payzant, Andrew mailto:payza...@ornl.gov>> Sent: Thursday, July 25, 2019 9:08 AM To: Mibeck, Blaise mailto:bmib...@undeerc.org>> Cc: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr> mailto:rietveld_l@ill.fr>> Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater STOP!!! The tantalum foil should not be used for high temperature in air. Above a few hundred degrees Celsius it will oxidize rapidly and disintegrate. I accidently learned this the hard way many years ago! Either use an inert atmosphere or vacuum. Or use a different heater ribbon, suitable for air atmosphere. Andrew * Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Neutron Sciences Directorate Mailing address: Oak Ridge National Laboratory Dr. E. Andrew Payzant P.O. Box 2008 Bldg. 8600, MS 6475 Oak Ridge, TN 37831 cell: (865) 235-4981 email: payza...@ornl.gov<mailto:payza...@ornl.gov> https://www.ornl.gov/staff-profile/e-andrew-payzant ** From: mailto:rietveld_l-requ...@ill.fr>> on behalf of "Mibeck, Blaise" mailto:bmib...@undeerc.org>> Reply-To: "Mibeck, Blaise" mailto:bmib...@undeerc.org>> Date: Thursday, July 25, 2019 at 10:03 AM To: Rietveld list mailto:rietveld_l@ill.fr>> Subject: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater I am looking for
RE: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater
Actually, i wouldn't recommend that either My experience with the Ta heaters is that they react with even the smallest amount of oxygen, and bottled N2 has more than enough to kill a Ta strip. The best result we had was with a H2/N2 mix, but that still failed (probably reaction with the sample). Personally I think the only reliable way to use them is with a high vacuum system (turbo pump), and with relatively inert samples. Ultimately you are better off getting a Pt strip instead. Jools From: rietveld_l-requ...@ill.fr On Behalf Of Mibeck, Blaise Sent: torsdag 25. juli 2019 16.27 To: Payzant, Andrew Cc: rietveld_l@ill.fr Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater Thank you -- I will try nitrogen then! From: Payzant, Andrew mailto:payza...@ornl.gov>> Sent: Thursday, July 25, 2019 9:08 AM To: Mibeck, Blaise mailto:bmib...@undeerc.org>> Cc: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr> mailto:rietveld_l@ill.fr>> Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater STOP!!! The tantalum foil should not be used for high temperature in air. Above a few hundred degrees Celsius it will oxidize rapidly and disintegrate. I accidently learned this the hard way many years ago! Either use an inert atmosphere or vacuum. Or use a different heater ribbon, suitable for air atmosphere. Andrew * Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Neutron Sciences Directorate Mailing address: Oak Ridge National Laboratory Dr. E. Andrew Payzant P.O. Box 2008 Bldg. 8600, MS 6475 Oak Ridge, TN 37831 cell: (865) 235-4981 email: payza...@ornl.gov<mailto:payza...@ornl.gov> https://www.ornl.gov/staff-profile/e-andrew-payzant ** From: mailto:rietveld_l-requ...@ill.fr>> on behalf of "Mibeck, Blaise" mailto:bmib...@undeerc.org>> Reply-To: "Mibeck, Blaise" mailto:bmib...@undeerc.org>> Date: Thursday, July 25, 2019 at 10:03 AM To: Rietveld list mailto:rietveld_l@ill.fr>> Subject: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater I am looking for advice on how to prepar a HTXRD sample (mounting techniques, stage preparation, etc...). The ribbon heater is tantalum (brand new). The sample contained ammonium di-hydrogen phosphate. The atmosphere is air. I hope to reach at least 1100C, but have had the ribbon break before 750C. Corrosion? or can the sample lower electrical resistance? Please, any advice. All the best, Blaise ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater
Thank you -- I will try nitrogen then! From: Payzant, Andrew Sent: Thursday, July 25, 2019 9:08 AM To: Mibeck, Blaise Cc: rietveld_l@ill.fr Subject: Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater STOP!!! The tantalum foil should not be used for high temperature in air. Above a few hundred degrees Celsius it will oxidize rapidly and disintegrate. I accidently learned this the hard way many years ago! ? Either use an inert atmosphere or vacuum. Or use a different heater ribbon, suitable for air atmosphere. Andrew * Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Neutron Sciences Directorate Mailing address: Oak Ridge National Laboratory Dr. E. Andrew Payzant P.O. Box 2008 Bldg. 8600, MS 6475 Oak Ridge, TN 37831 cell: (865) 235-4981 email: payza...@ornl.gov https://www.ornl.gov/staff-profile/e-andrew-payzant ** From: on behalf of "Mibeck, Blaise" Reply-To: "Mibeck, Blaise" Date: Thursday, July 25, 2019 at 10:03 AM To: Rietveld list Subject: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater I am looking for advice on how to prepar a HTXRD sample (mounting techniques, stage preparation, etc...). The ribbon heater is tantalum (brand new). The sample contained ammonium di-hydrogen phosphate. The atmosphere is air. I hope to reach at least 1100C, but have had the ribbon break before 750C. Corrosion? or can the sample lower electrical resistance? Please, any advice. All the best, Blaise ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater
STOP!!! The tantalum foil should not be used for high temperature in air. Above a few hundred degrees Celsius it will oxidize rapidly and disintegrate. I accidently learned this the hard way many years ago! Either use an inert atmosphere or vacuum. Or use a different heater ribbon, suitable for air atmosphere. Andrew * Dr. E. Andrew Payzant Materials Engineering Group Leader Neutron Scattering Division Neutron Sciences Directorate Mailing address: Oak Ridge National Laboratory Dr. E. Andrew Payzant P.O. Box 2008 Bldg. 8600, MS 6475 Oak Ridge, TN 37831 cell: (865) 235-4981 email: payza...@ornl.gov https://www.ornl.gov/staff-profile/e-andrew-payzant ** From: on behalf of "Mibeck, Blaise" Reply-To: "Mibeck, Blaise" Date: Thursday, July 25, 2019 at 10:03 AM To: Rietveld list Subject: [EXTERNAL] Mounting Sample on High Temperature XRD Ribbon Heater I am looking for advice on how to prepar a HTXRD sample (mounting techniques, stage preparation, etc...). The ribbon heater is tantalum (brand new). The sample contained ammonium di-hydrogen phosphate. The atmosphere is air. I hope to reach at least 1100C, but have had the ribbon break before 750C. Corrosion? or can the sample lower electrical resistance? Please, any advice. All the best, Blaise ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
