激光打孔对氮化铝绝缘性能的影响

氮化铝陶瓷具有优良的绝缘和导热性能,是传导冷却超导电力装置绝缘与导热连接件的首选,激光切割是对其进行加工的最有效方法,但激光切割可能对其绝缘性能产生影响,进而影响超导电力装置的安全运行。基于此,通过对激光打孔前后氮化铝基片孔周区域绝缘电阻的测量、金相结构和扫描电镜成分的比较,分析了激光打孔对氮化铝绝缘性能的影响,并总结了选用氮化铝基片作为超导电力装置电流引线的绝缘与导热垫片应注意的问题。

The impact of laser drilling on insulating strength of AlN ceramics

AlN ceramics have good insulating and thermal conducting properties.It is the preferred material for the thermal conducting conjunction of a cryocooler-cooling superconducting power device.At present,laser drilling is the most effective processing approach for AlN.But laser drillinginduced local high temperature could result in microstructural damage to AlN substrates and could bring an influence in insulting property of AlN.Furthermore,the operating security of the superconducting power device will be threatened.Therefore,A series of experiments are fulfilled to make clear the impact on insulating strength of AlN ceramics by laser drilling.When laser drilling parameters are changed,changes of the microstructure and elements of AlN around the hole are analyzed,and the reasons are discussed.As well as some approaches to suggested in enhancing the insulating strength of a AlN substrate around the hole.Finally,some matters of the thermal conducting conjunction of a superconducting power device are summarized.