Effect of the BN content on the thermal shock resistance and properties of BN/SiO₂ composites fabricated from mechanically alloyed SiBON powders

Abstract

Wave-transparent composites of BN/SiO2 were prepared via hot pressure sintering at 1650 °C of mechanically alloyed amorphous SiBON powders.

Slip-Cast Fused Silica Radomes for Hypervelocity Vehicles: Advantages, Challenges, and Fabrication Techniques

“…Owing to these properties, BN has not been seriously considered for radome applications because radomes of BN cannot be fabricated in large shapes, and even if a fabrication technology is developed, its cost would probably be prohibitive [3,4,[44][45][46][47][48][49]. However, BeO and BN both are good candidates for small windows operating at Mach 8 or higher [44][45][46][47][48][49]. Figure 12 shows the change in the dielectric constant as a function of temperature for a number of candidate radome materials at X-band frequency [5].…”

“…The various methods and additives utilized so far for enhancing the strength of the fused silica ceramics are summarized in Table 12. The fused-silica composites produced so far are nano-sized silica-silica [70], silica fibers (SiO 2f ) reinforcedsilica [8,82], 3D SiO 2f -SiO 2 [80,83], 2.5D braided silica fibers reinforced nitride (SFRN) [84], silicon nitride (Si 3 N 4 )-doped silica [85], air-oxidized silica and Si 3 N 4 [86], zirconia (ZrO 2 ) doped silica [34], alumina doped silica [87], β-Si 4 Al 2 O 2 N 6silica [10,88,89], and BN-silica [44][45][46][47][48]90] as listed in Table 12 [1,2,4,5,36,61]. Various dopants were also added to confer different properties to fused silica ceramics consolidated by several techniques [1,2].…”

BN as a Saturable Absorber for a Passively Mode‐Locked 2 µm Solid‐State Laser

“…Compared to novel materials such as graphene, BP, and TMDCs, BN, is a traditional 2D nano‐sheet material with a band gap of 0.3–6 eV. BN has been a highly attractive material in various fields for many years as a result of its properties which include low abrasion, fire resistance, a low dielectric constant, low dielectric loss, high thermal conductivity, and resistance to corrosion and oxidation . However, the optical characteristics of BN have not been fully reported, with only some studies investigating the optical absorption from the BN material.…”

“…Pulse trains were recorded in 400 (Figure c), 40 (Figure c), 20 (Figure c), and 10 ns (Figure c) time scales. The pulse width was calculated with the rise time of the detector, oscilloscope, and measurements from the formulae (1) and (2) …”

Fabrication and properties of Si2N2O ceramics for microwave sintering furnace

“…Therefore, it is necessary to develop thermal insulation and wavetransparent materials for high temperature application in microwave sintering technique. So far, there are several high performance wave-transparent materials, such as β-SiAlON ceramics [6][7][8], Si 3 N 4 ceramics [9][10][11], SiO 2 ceramics [12,13], Si 2 N 2 O ceramics [14][15][16] and related composite materials [17][18][19][20]. Among them, the Si 2 N 2 O ceramics is the only compound in the SiO 2 -Si 3 N 4 system and it has the lowest dielectric constant (6.0).…”