1.Aln Basic Properties   Crystal Structure: Hexagonal wurtzite structure (similar to boron nitride and silicon carbide), characterized by high hardness, high melting point, and excellent thermal stability. Color: Typically grayish-white or light gray powder; pure single crystals can appear colorless and transparent. Density: 3.26 g/cm³. Melting Point: Approximately 2200°C (can reach up to 2500°C without decomposition under high-pressure nitrogen).   2.Characteristics and Advantages   High Thermal Conductivity: Theoretical value up to 320 W/(m·K), comparable to beryllium oxide (BeO) and copper, but non-toxic, making it an ideal thermal management material. Wide Bandgap: 6.2 eV (electron volts), suitable for high-temperature, high-power, and ultraviolet optoelectronic devices. Electrical Insulation: High resistivity (>10¹⁴ Ω·cm) and low dielectric constant (~8.8), ideal for high-frequency electronic devices. Chemical Stability: Resistant to acid and alkali corrosion (especially in dry environments), but slowly hydrolyzes in high-temperature humid air. Thermal Expansion Coefficient: 4.5×10⁻⁶/K (close to silicon), making it compatible with silicon-based chips.   3.Preparation Methods   Chemical Vapor Deposition (CVD): Used to produce high-purity thin films or single crystals. Direct Nitridation: Aluminum powder reacts with nitrogen or ammonia at high temperatures (800–1200°C). Carbothermal Reduction: Aluminum oxide mixed with carbon reacts in nitrogen at high temperatures (1600–1800°C). Sol-Gel Method: Suitable for synthesizing nano-sized powders.   4.Applications   Semiconductor Devices: High-temperature and high-frequency components (e.g., RF modules for 5G communication), substrates for UV LEDs. Electronic Packaging: High thermal conductivity substrates (e.g., heat sinks for LEDs and power modules). Surface Acoustic Wave (SAW) Devices: Due to high acoustic velocity (~6000 m/s) and low signal loss. Structural Ceramics: High-temperature crucibles, cutting tool coatings. Composite Materials: Mixed with polymers to enhance thermal conductivity (e.g., thermally conductive plastics).   5.Precautions   Toxicity: Powder may irritate the respiratory tract; protective measures are required. Processing Difficulty: High hardness increases cutting and polishing costs, often requiring hot pressing or spark plasma sintering (SPS) techniques.   6.Comparison with Other Materials   VS Aluminum Oxide (Al₂O₃): Thermal conductivity is over 10 times higher, but cost is also higher. VS Silicon Nitride (Si₃N₄): Aluminum nitride offers better thermal conductivity but slightly lower mechanical strength.   Aluminum nitride (AlN) holds an irreplaceable position in advanced electronics and high-temperature technologies due to its unique combination of properties. With the growth of 5G and electric vehicles, its demand continues to rise.

NOVATEK can provide a range of crucibles for electron guns, which can also be designed and customized to meet specific needs. May I know if you have chosen the most suitable crucible for aluminum plating? This article explains in detail how to choose it, let’s go down.   BN-TiB2 Crucibles   Aluminum will form alloys with tungsten crucibles, molybdenum crucibles, and tantalum crucibles, which cause corrosion on the inside of the crucible and also contaminate aluminum. At the same time, the film layer has been contaminated, such as the film being black, dark, and even spotted. Aluminum will also form yellow aluminum carbide with carbon in graphite crucibles, and the formed aluminum carbide will evaporate onto the sample, causing the film to turn yellow. The use of boron nitride crucibles, alumina crucibles, or quartz crucibles is prone to electron beam defocusing issues. The main reason is that the crucible is not conductive, and the excess electrons in the crucible accumulate, resulting in repulsion of the electron beam. The use of conductive boron nitride crucible aluminum plating can effectively solve the problems encountered with ordinary crucibles. The aluminum film is of high quality and the crucible has a long service life.   Common Causes of Crucible Breakage: The first reason is that the ramp/soak levels are wrong for that material. The second reason the user shuts the power supply off or has a very short ramp down time for power after the deposition is done. This causes the rapid solidification of the melt, and this stresses out the crucible liner.   Advantages of BN-TiB2 Crucibles: 1. Custom sizes available upon request. 2. The crucible is conductive and the electron beam can work normally. 3. It will not pollute the aluminum, and the plated aluminum film has high purity. 4. Recommended for aluminum evaporation. 5. The special design can effectively reduce the power of the electron gun. 6. The special design makes the crucible not easy to crack. 7. Intermetallic crucibles are both conductive and lubricious and are ideal for materials that have a tendency to creep up the sides of the crucible.   Intermetallic (BN-TiB2) E-Beam Crucibles   NOVATEK  produces a series of crucibles, and you can pick up according to the specific requirements and areas of application. If you need any E-Beam Crucibles, please feel free to contact us.

Brazing-ceramic is a special case of joining materials. The technologies developed to perform the joining of ceramics to themselves or to other materials are different from most other brazing processes. Ceramics, as everybody knows, are hard and brittle with nil ductility, and limited tolerance for tensile stresses. Therefore if possible, ceramics are designed to be stressed in compression. Although used as thermal insulators, they are sensitive to thermal shocks. However, within limits, their properties can now be adapted to intended uses, especially by including in the mass strengthening (reinforcing) particles, fibres or whiskers. And also by causing process induced structural transformations to enhance their suitability to various applications. The main differences in Brazing-ceramic as opposed to metals stem from the fact that most regular brazing materials do not wet ceramics. This is due to the basic physical properties of these materials, like their strong ionic and covalent bonding. Furthermore, as ceramics have greater thermodynamic stability than metals, strong chemical bonds to enhance adhesion are not easy to form. In the present increasing use of ceramics, due to the economic importance of joining them, of the many different methods applicable to perform acceptable joints, the most important and adaptable is probably still Brazing-ceramic. Earlier ceramics were intended to withstand service at room temperature, essentially displaying insulating properties and wear resistance (in absence of shocks). The development of more advanced types was promoted by the challenge to confront service conditions at elevated temperatures, in oxidizing or corrosive environments with substantial mechanical properties. In particular, there is a major drive to find uses for ceramic in thermal engines and in energy-producing facilities for recovering waste heat. All these may need Brazing-ceramic. The new developments are now called structural ceramics to signify their ability to meet exacting requirements in demanding service conditions. It should be noted that ceramics can be monolithic or ceramic matrix composites. Within each type designation or family, say Alumina, various classes are included that, depending on processing parameters, may exhibit quite different structural and mechanical properties. Another consideration to keep in mind is that it may be quite difficult if not impossible to get tabulated design properties from handbooks or manuals. That is because test results depend heavily upon specimen preparation and size, and on the type of test. Also, joint design can have much influence on the success of the Brazing-ceramic joining process. The reason is the substantial difference in the Coefficient of Thermal Expansion (CTE) between ceramics and metals, a fact that may introduce high stresses and possibly cracks conducive to failures. Only exceptionally one can find a ceramic having CTE in the range of some low-expansion metals, a quite rare and welcome occurrence for performing Brazing-ceramic successfully. One strategy often employed for bridging the gap in CTE values consists in designing joints to be stressed in compression. Or, for widely different values of CTE, to interpose intermediate materials to provide a gradual passage from the minimum to the maximum of that property. To promote the wetting of ceramics by filler metal and its adhesion to the surface, the following techniques are used: 1) – Indirect Brazing-ceramic by first coating the ceramic surface in the joint with material, usually a metal, suitable to be wetted by a regular filler metal that would not wet untreated ceramic surfaces. The metallic coating acts as a transition material between metal and ceramic. Care must be taken to avoid that the coating sintering heat cycle crack the ceramic. Typical in this class is the well known Molybdenum-Manganese coating. A slurry of specially prepared powders is applied to the ceramic as a paint. It is then fired in a hydrogen atmosphere furnace at about 1500 °C (2730 °F) that causes glassy materials from the ceramic to migrate to the metal powder bonding it to the surface. Other applied coating techniques resort to physical vapour deposition (PVD) for sputtering metals. Brazing-ceramic is then performed with regular brazing filler metals suitable to the metal to be joined. 2) – Direct Brazing-ceramic by using Active Filler Metals containing special alloying elements. The addition to regular silver-based brazing alloys, of metals having a strong affinity for the elements constituting the ceramic, promotes wetting and adhesion. Thus, metals having a strong affinity for oxygen, like titanium, aluminium, zirconium, hafnium, lithium, silicon or manganese help conventional brazing alloys in wetting oxide ceramics without special preparation. Metals that react with silicon, carbon or nitrogen help wetting silicon carbide or silicon nitride. Quite a few Active Filler Metals were developed over the years for scientific investigations and some of these are available commercially from known manufacturers (GTE Wesgo, Degussa AG, Lucas-Milhaupt, Handy & Harman). It seems improbable though, that off the shelf materials can be procured and used in new applications of standard Brazing-ceramic processes without thorough study and preparation. Two other cases should be presented in this context due to their large diffusion. One is the brazing of carbide tips to steel shanks. Carbide tools are usually manufactured by sintering titanium-, tantalum- or niobium-carbide with a cobalt binder. Other carbides and other metal binders are also used. Silver base brazing filler metals containing nickel, like BAg-3, BAg-4 and BAg-22 have been successfully used. Tungsten carbide tools need a special sandwich filler metal including a copper shim to reduce residual stresses. The other case refers to Silicon carbide tools, brazed using a Titanium base filler metal, or a titanium-containing silver-copper or nickel-titanium brazing alloys. In conclusion, Brazing-ceramic although not simple to perform is a necessity if the special properties of ceramic materials of the most diverse types have to be exploited in actual implements. A thorough study and experimental development must be devoted as needed to obtain successful results.

Gas atomization is a kind of high efficient technique to produce high-quality metal powders. It makes the metal powders with spherical shape, clean surfaces and uniform particle sizes. And gas atomization is becoming more and more popular in modern powder production due to its high quality production. In order to support the processing of gas atomization, NOVAATEK presents a series of atomizing nozzles including Boron Nitride and Zirconia material. We have BMA, BSC, BMZ, BAN and BSN which are all well used for metal powder’s atomization, especially BMA and BMZ are very popular. Hot pressed Boron Nitride nozzles are often used for producing nickel powder, copper powder and aluminum powder. The max working temperature is 1700- 1800℃ in vacuum. The benefits of BN atomizing nozzles 1.Non wetting make it reduce the frequency of nozzle replacement 2.Good surface finish make tolerances better 3.Very good thermal shock resistance makes BN not have to be pre-heating widely Besides Boron Nitride nozzles, NOVATEK also supplies Zirconia nozzles for powder metal atomization. This is also a very good option on material for the gas atomization. The max working temperature for the Zirconia is 2000℃ in air, vacuum or atmosphere protection environment. Zirconia nozzles are available for almost all metal and alloy powders except tungsten, molybdenum powders.   The benefits of Zirconia nozzles 1.High thermal resistance make it excellent performace in high temperature atomization 2.Very good wear resistance 3.Chemical inertness make the nozzles not reactivity with atomized alloys 4.Low thermal conductivity