Reliability of Additively Manufactured Resistors for High Temperature with Glass Encapsulation

This is the authors' abstract. We don't add key points for this paper.

Integrating electronics into high temperature aerospace platforms can be a difficult task as there are many competing challenges such as finding compatible materials, surface area, and reliability. Passive components like resistors offer a particular challenge at elevated temperatures as their performance changes greatly based on the surrounding temperatures. Additive manufacturing (AM) offers a solution to both integration and fabrication challenges. Here we investigate two resistive materials under stressful conditions such as humidity aging, thermal aging, and thermal cycling both with and without encapsulation. A Nordson EFD Pro 4 was used for this work to dispense all materials, additionally alumina substrates were used for their ubiquity in high temperature environments. Two resistive pastes were used and one encapsulant material. Reliability was assessed by measuring resistance changes after exposure to environments such as thermal aging at 300°C for 100 hours, humidity aging at 85C/85% RH for 288 hours, and thermal cycling from -55 to 155 for 100 cycles. The adhesion of the Ink A, Ink B, and the encapsulant is 20.43 ± 12.73 kgF, 32.17 ± 6.99 kgF, and 22.38 ± 9.26 kgF respectively. After adhesion was assessed, the resistors were fabricated. In all simulated environments the resistance of the fabricated devices remained consistent. In summary, the reliability of high temperature electronics is of great importance as these environments put many stresses on resistors and components of all kind in a circuit. Here we demonstrated two materials suitable for higher temperature resistors and the impact of a glass based encapsulant. In the future researchers should investigate higher temperatures with a different encapsulant material to increase the thermal budget.