Wetting, reactivity, and phase formation at interfaces between Ni–Al melts and TiB₂ ultrahigh‐temperature ceramic

Abstract

The wetting, reactivity, and phase formation at the liquid Ni–Al/TiB2 ceramic interfaces have been investigated at the temperatures close to the Ni–Al liquidus line. The wetting kinetics has been studied by the sessile drop technique utilizing liquid drop dispension and high‐speed high‐resolution video imaging. It is established that the wetting behavior changes from a nonreactive for the Al‐rich melts to a dissolution‐reactive for the Ni‐rich melts. For the Ni concentration ≥40 at.%, TiB2 precipitates are found in the solidified Ni–Al droplets after the high‐temperature interaction of the melts with TiB2 substrates. Besides, new (Al,Ti)Ni3 and (Al,Ti)2Ni21B6 phases are formed due to dissolution of TiB2 ceramic in Ni‐rich melts and subsequent solidification.

Wetting Effect on Patterned Substrates

“…Reproduced with permission. [67] Copyright 2017, American Ceramic Society, published by John Wiley and Sons. liquid transport based on the surface structure as well as the surface tension of the liquid.…”

“…Reproduced with permission. [ 67 ] Copyright 2017, American Ceramic Society, published by John Wiley and Sons.…”

“…e) An alloy of Al-Ni droplets is placed on the top of TiB 2 ceramic materials at elevated temperatures greater than 700 °C. Reproduced with permission [67]. Copyright 2017, American Ceramic Society, published by John Wiley and Sons.…”

Wettability and interfacial phenomena in the liquid‐phase bonding of refractory diboride ceramics: Recent developments

“…While boron does not significantly lower the liquid/vapor interfacial energy, its adsorption at the TiB 2 surface and its role in reducing a native TiO 2 film on TiB 2 via a ''cleansing" reaction(1.5TiO 2(s) + 2[B] (l) → B 2 O 3(g) + 1.5[Ti] (l)) improve the wetting. Similar improvements from oxide reduction were reported by Weirauch58 for wetting of TiB 2 with Al.In Ni-Al alloys with different amounts of Al, wetting of TiB 2 is nonreactive in Al-rich melts, whereas it is controlled by a dissolution-reaction mechanism in Ni-rich Al melts in which TiB 2 precipitates form within solidified droplets at high (≥40 at.%) Ni contents 60. Additionally, dissolution of TiB 2 substrate in Ni-rich Al melt forms new phases such as (Al,Ti)Ni 3 and (Al,Ti) 2 Ni 21 B 6 .…”