Ceramic beam tubes are utilized in numerous kicker magnets in different accelerator rings at Fermi National Accelerator Laboratory. Kovar flanges are brazed onto each beam tube end, since kovar and high alumina ceramic have similar expansion curves. The tube, kovar flange, end piece, and braze foil (titanium/incusil) alloy brazing material are stacked in the furnace and then brazed in the furnace at 1000 °C. The ceramic specified is 99.8% Alumina, Al_2O_3, a strong recrystallized highalumina fabricated by slip casting. Recent experience at Fermilab with the fabrication and brazing of these tubes has brought to light numerous problems including tube breakage and cracking and also the difficulty of brazing the tube to produce a leak-tight joint. These problems may be due to the ceramic quality, voids in the ceramic, thinness of the wall, and micro-cracks in the ends which make it difficult to braze because it cannot fill tiny surface cracks which are caused by grain pullout during the cutting process. Solutions which are being investigated include lapping the ends of the tubes before brazing to eliminate the micro-cracks and also metallization of the tubes.
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机译：陶瓷束管在Fermi National Accelerator实验室的不同加速器环中的许多踢球磁铁中使用。 Kovar Flanges钎焊到每个梁管端上，因为Kovar和高氧化铝陶瓷具有类似的膨胀曲线。管，KOVAR法兰，端部件和钎焊箔（钛/侵蚀）合金钎焊材料堆叠在炉内，然后在1000℃下钎焊。指定的陶瓷是99.8％氧化铝，Al_2O_3，一种由滑铸造的强重结晶的霍华氨基。最近在Fermilab与这些管的制造和钎焊的经验已经揭示了众多问题，包括管断裂和裂缝，以及钎焊管以产生泄漏的关节。这些问题可能是由于陶瓷质量，陶瓷，壁的薄度空隙，并且末端的微裂纹，使其难以钎焊，因为它不能填充在切割过程中由谷物拉出引起的微小表面裂缝。正在研究的溶液包括在钎焊之前研磨管的端部以消除管道的微裂纹和金属化。
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