The Effect of Boron Content on Wetting Kinetics in Si-B Alloy/h-BN System

Abstract

In this work, the effect of boron content on the high-temperature wetting behavior in the Si-B alloy/h-BN systems was experimentally examined. For this reason, hypoeutectic, eutectic and hypereutectic Si-B alloys (Si-1B, Si-3.2B and Si-5.7B wt.%, respectively) were produced by electric arc melting method and then subjected to sessile drop/contact heating experiments with polycrystalline h-BN substrates, at temperatures up to 1750°C. Similar to pure Si/h-BN system, wetting kinetics curves calculated on a basis of in situ recorded drop/substrate images point toward non-wetting behavior of all selected Si-B alloy/h-BN couples. The highest contact angle values of 150°were obtained for hypoeutectic and eutectic Si-B alloys in the whole examined temperature range.

Silicon-Boron Alloys as New Ultra-High Temperature Phase-Change Materials: Solid/Liquid State Interaction with the h-BN Composite

“…What should be noted is that the Si-3.2B alloy shows a lower wettability (reflected by prominently higher contact angles) with the h-BN composite, than the pure silicon examined under the same testing conditions (θ 1450 = 132 • to θ 1750 = 110 • ) [16]. This finding confirms the previously observed effect of boron addition to silicon on suppressing high temperature wettability through hindering a dissolution of h-BN matrix in the molten alloy [11]. Interestingly, the wetting behavior of the Si-3.2B alloy/h-BN composite couple during cooling from 1750 • C is also quite different than that of previously examined Si/h-BN composite couple.…”

“…1 Temperature profiles of high temperature sessile drop experiments of the Si-3.2B alloy/h-BN composite couples carried out by: a step-heating up to 1750 • C with five intervals (a); a thermocycling including 15 heating/cooling cycles between 1300 and 1450 • C with the intermediate cooling to room temperature after 10 th cycle test was to examine the effect of testing temperature on wetting characteristics, and to establish applicability limits of selected materials. The same temperature profile was applied in our previous works [9,11,16]. The second type of the sessile drop test (Fig.…”

“…The materials investigated were eutectic Si-3.2B (wt%) binary alloy produced by electric arc melting method (details on applied process are shown elsewhere [11]) and the commercially available hot-sintered h-BN-24ZrO 2 -6SiC composite (Henze HeBoSint O120, Germany). The Si-3.2B alloy was produced from polycrystalline pure materials (Si: 99.999%; B: 99.9% as provided by Onyxmet, Poland).…”

“…In the present work we continue our research by examining for the first time the Si-3.2B eutectic alloy/(h-BN-24ZrO 2 -6SiC) system in sessile drop experiments carried out in accordance to step-heating or thermocycling procedures. In this regard, our previous works on Si/h-BN [9,10], Si-B/h-BN [11] and Si/ h-BN-24ZrO2-6SiC [16] systems tested under the same conditions are treated as direct references. In order to avoid repeating certain information, more details on applied materials and testing procedures are available in our previous works and referenced in proper places in manuscript.…”

Mo–Si–B alloys for ultra-high-temperature space and ground applications: liquid-assisted fabrication under various temperature and time conditions

“…Alloy samples were produced by melting the mixtures in capillaries (at 1500°C/30 min) followed by a melt deposition on ceramic substrates. Both capillaries and substrates were made of h-BN, which shows exceptional inertness towards Si-based melts at high temperature [20][21][22]. The mentioned process fabrication of alloy samples was carried out in a chamber of our experimental device (Fig.…”