Excessively High Vapor Pressure of Al-based Amorphous Alloys

Jae Jeong,Sung Lee,Suk Kim,Je-Beom Jeon

doi:10.3390/met5041878

Abstract

Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

Highlights

Sublimation is the phase transition from solid to gas, without passing through an intermediate liquid phase
This temperature range overlaps with the supercooled liquid region (SCLR) of the Al-based amorphous alloys measured in DSC (Figure 1b and Table 1)
The amount of weight loss varied with the composition of the amorphous alloys, and was inversely proportional to their glass-forming ability (GFA)

Summary

Introduction

Sublimation is the phase transition from solid to gas, without passing through an intermediate liquid phase. Many amorphous alloys exhibit liquid-like behavior at temperatures substantially below their melting temperatures. We previously exploited the liquid-like behavior of Al-based amorphous alloys in SCLR to develop Ag paste for solar cells [5,6,7]. This is likely because AYNC has higher thermoplastic formability [8], so AYNC is more deformed in SCLR by capillary forces in the paste, which enhanced the electrical properties of the Ag electrodes. For materials in solid phase, the vapor pressure was estimated by measuring and extrapolating the vapor pressure from a supercooled liquid phase immediately below the melting temperature. Measurements of the vapor pressures of amorphous alloys in SCLR well below the melting temperatures have not been reported

Experimental Section

Results and Discussion

Conclusions