Aerosol jet 3D printing and high temperature characterization of nickel nanoparticle films

Three-dimensional (3D) nanoparticle printing has emerged as a versatile and environmentally friendly manufacturing technique to fabricate metallic films for microelectronic applications. In this letter, we report the synthesis of 500 nm thick nickel films by aerosol jet nanoparticle printing and assess their stability at high temperatures. In-situ impedance spectroscopy is used to measure the electrical properties of the films from 25 degrees C to 500 degrees C, at frequencies from 0.02 kHz to 300 kHz. It is observed that the real part of impedance of the films increases from room temperature to 350 degrees C monotonously, indicating a positive temperature coefficient of resistance (TCR). Upon further heating, however, the films exhibit an unstable electrical behavior, with TCR increasing by two orders of magnitude between 350 degrees C and 500 degrees C. Thermogravimetric analysis (TGA) of nickel nanoparticles was performed to understand the underlying reason of electrical instability beyond 350 degrees C, which showed that the particle oxidation starts at about 325-350 degrees C and leads to a mass gain of 19.35% at 500 degrees C, indicating significant thermal oxidation. The electrical stability of the films at high temperatures is thus controlled by their thermal oxidation, which starts at a much lower temperature (350 degrees C) when compared to bulk nickel (600 degrees C). Implications of this result on the applicability of the 3D printing method to synthesize metal films for high temperature applications are discussed. (C) 2021 The Authors. Published by Elsevier Ltd on behalf of Society of Manufacturing Engineers (SME).

Automated summary

In this letter, the synthesis of 500 nm thick nickel films by aerosol jet nanoparticle printing and their stability at high temperatures were reported. The films exhibited a positive temperature coefficient of resistance up to 350 degrees C, but showed unstable electrical behavior beyond that temperature range. Thermogravimetric analysis of nickel nanoparticles indicated significant thermal oxidation beyond 350 degrees C, affecting the electrical stability of the films.