Being refractory and X-ray transparent, a boron-doped diamond (BDD) heater is considered an ideal heating element in a multi-anvil apparatus under diamond-stable pressures. However, the extremely high hardness of diamond makes it difficult to manufacture a BDD tube, which, in turn, hinders the wide application of BDD heaters in multi-anvil apparatuses. Here, I sintered a machinable BDD (MBDD) from a mixture of BDD powder and pitch (C_nH_2n+2) by its annealing in Ar at 1273 K for 5 h. The BDD powder was bound by a small amount of graphite (<10 wt. %) during the sintering process. Tubes (such as 1.2/0.7/4.0 mm in outer/inner diameter/length) can be manufactured from the MBDD block using a lathe or a computer numerical control machine. Due to the low content of graphite in MBDD, the graphite–diamond conversion has a small effect on heating performance. The MBDD heater shows a comparable performance in ultrahigh temperature generation with a high-pressure synthesized BDD heater by generating a temperature higher than 3300 K and melted Al₂O₃ under a pressure of 15 GPa. With good heating performance and excellent machinability, MBDD is a practical heating element in multi-anvil apparatuses. The achievement of stable temperature generation over 3300 K by the MBDD heater enables various measurements on the physicochemical properties of melts under the Earth’s mantle conditions.

中文翻译：

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可加工的掺硼金刚石作为多砧装置中的实用加热元件

硼掺杂的金刚石（BDD）加热器具有耐火性和X射线透明性，在金刚石稳定的压力下，被认为是多砧装置中的理想加热元件。然而，金刚石的极高硬度使其难以制造BDD管，这反过来又阻碍了BDD加热器在多砧装置中的广泛应用。在这里，我从BDD粉末和沥青（C _n H _{2n + 2}），将其在Ar中于1273 K退火5 h。在烧结过程中，BDD粉末被少量的石墨（<10 wt。％）粘结。管子（外径/内径/长度为1.2 / 0.7 / 4.0毫米）可以使用车床或计算机数控机床由MBDD块制造。由于MBDD中的石墨含量低，石墨-金刚石转化对加热性能的影响很小。通过产生高于3300 K的温度和熔化的Al ₂ O ₃，MBDD加热器在高压合成BDD加热器中表现出与超高温相当的性能在15 GPa的压力下。MBDD具有良好的加热性能和出色的可加工性，是多砧装置中实用的加热元件。MBDD加热器可在3300 K以上的温度下产生稳定的温度，因此可以在地幔条件下对熔体的理化性质进行各种测量。