Abstract:the processing technology of the helical traveling wave tube with the inclined T-shaped boron nitride clamping rod with the arc surface plays an indispensable role in communication and electronic countermeasures. The clamping rod in the slow wave circuit acts as the helix and the tube shell. The supporting transition piece between the tubes plays a role of heat conduction and conducts the heat generated in the tube to the outer surface of the tube shell in time. Two materials widely used in traveling wave tubes are beryllium oxide and anisotropic boron nitride.
Pyrolytic Boron Nitride (PBN) is a kind of advanced ceramic, that can be produced with 99.999% purity in high density. It is made by ammonia and Boron halide through a Chemical Vapor deposition(CVD) process in high temperature and high vacuum conditions:NH3 +BX3=BN+3HX , it can be produced as PBN plates, and also can be produced as PBN final products directly like a crucible, boat, coating, etc.
2. Main Features
It’s different from BN, there is no traditional process of hot pressing, no need for any kinds of agglutinant, so the products have very obliviously features as follow:
- ● Non-toxic and tasteless
- ● High purity(＞99.999%)
- ● No reaction with acid, alkali, salt, and another organic reagent at room temperature
- ● A little corrode in melt salt and alkali, but it can resist any acid at high temperatures.
- ● No reaction with melt metal, semiconductor, and other compounds.
- ● Excellent oxidation resistance below 1000℃
- ● Excellent thermal shock resistance
- ● Can be used in high-temperature, no sublimation point will be decompose into B&N
- ● High electrical resistance, suitable electrical insulating property
- ● Smooth surface, pore-free, not melt with most semiconductor
- 3. Product Application
- ● Crystal growth (VGF, LEC Crucible)
- ● Molecular Beam Epitaxy(MBE) Crucible
- ● Polycrystalline Synthesis Boat
- ● OLED and MBE Effusion Cell
- ● MOCVD Heater
- ● PBN Infrared Window
- ● Traveling Wave Tube (TWT) (PBN Support Rod)
- ● PBN Coating Graphite
- ● High temperature, vacuum equipment insulator
- 4. Parameter of PBN
|Thermal Conductivity||W/m°C||“a” 60 “c” 2|
|Dielectric Strength||D.C. volts/mm||2×105|
|Dielectric Constant||“c” 3.07|
|Metal Impurity Content||ppm||<10|