Boron-doped diamond synthesized by chemical vapor deposition as a heating element in a multi-anvil apparatus

Simultaneous generation of ultrahigh pressure and temperature to 50 GPa and 3300 K in multi-anvil apparatus

“…Interestingly, the thermocouple reading seemed to recover after cooling to 2673 K. The power-temperature relationships for heating and cooling below 1800 K are consistent with each other. The power-temperature curve shows a bend during cooling, which is commonly observed in BDD heaters, 14,[18][19][20][21] but shows approximately a linear shape during the heating. For a conservative estimate, we estimated the highest temperature at the maximum applied power (1154 W) to be 3300 K by linear extrapolation of the power-temperature relationship obtained up to 1800 K.…”

“…Although the pre-synthesized high-pressure BDD was used in the first run, we used a CVDsynthesized BDD tube as a heater in this run because this type of BDD can be purchased commercially. 19 A CVD-BDD block with a boron content of 0.5 wt. % (Changsha 3 Better Ultra-hard Materials Co. Ltd., China) was shaped into a tube using a green laser by Dutch Diamond Technologies BV.…”

“…For example, a BDD heater synthesized at high pressure and temperature expanded the temperature range to 4000 K at 15 GPa. 18 In addition, the adoption of BDD synthesized by the chemical vapor deposition (CVD) method 19,20 and the development of machinable BDD block 21 made it possible to use BDD as a routine heating element in multi-anvil apparatus. Owing to its high x-ray transparency, BDD also shows a great advantage for in situ multi-anvil experiments.…”

Extreme conditions research using the large-volume press at the P61B endstation, PETRA III

“…Skilled experimentalists may orient the cylindrical heater horizontally, in the direction of the X-ray beam axis. Alternatively, other nearly X-ray transparent heaters can be used at high pressures without modifying the assembly significantly, such as TiB 2 +hBN, generating stable temperatures exceeding 1900 K. A new heater material, B-doped diamond, is now routinely used (Nishida et al, 2020;Xie et al, 2020). It can generate temperatures over 3500 K and is X-ray transparent.…”