PTA processing of Nb based coatings
Abstract
This project will focus on the design and implementation of an environmental protection “system” to deposit a suitable silicide coating on a Nb alloy during Plasma Transferred Arc deposition while minimizing oxidation and incorporation of interstitials in the coating and the base alloy. Two approaches will be evaluated to design the protection system: A fix system and a flexible system. The concept of each approach is represented below. In both cases, samples will be positioned on a coordinate table, which will be confined within a chamber filled with argon gas. In the “fix system” approach the movements of the plasma torch are restricted whereas in the “flexible system” approach wide range movement of the robotic arm that helds the plasma torch, is preserved. Before deposition the chamber has to be purged and the oxygen content reduced to a minimum, after which the plasma arc can be ignited to start deposition. The challenge is to minimize/eliminate the presence of oxygen during deposition of coatings allowing the identification of the processing conditions leading to a minimum, tolerable oxygen content.Initial tests of the protection system will be carried out reproducing previous experiments using Nb-Al-Si powder mixtures [PhD thesis, K. Graf, UFPR, 2009 and PhD thesis G F. Menegotti, UFPR, in progess]. During this tests the argon gas flow and the O2 content in the system will be evaluated. The deposited Nb-Al-Si powder mixtures with, and without, the protection system and tested at temperatures up to 1100C to assess the oxidation behavior.Once the system is tested and approved, deposition of a silicide coating ( ex: powder mixtures of Nb+R512E (Si-20Cr-20Fe) on a Nb commercial alloy substrate ( ex: C103-Nb-10Hf-1Ti) will be deposited and its performance tested and correlated with data from the literature.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 03, 2017
- Source ID
- N62909151N083
Entities
People
- Ana Sofia Climaco Monteiro D Oliveira
Organizations
- Office of Naval Research
- United States Navy