Powder Materials for Energy Applications: Metal Powder Materials
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Powder Materials Committee
Program Organizers: Kathy Lu, University of Alabama Birmingham; Eugene Olevsky, San Diego State University; Hang Yu, Virginia Polytechnic Institute And State University; Ruigang Wang, Michigan State University; Isabella Van Rooyen, Pacific Northwest National Laboratory

Monday 8:30 AM
March 15, 2021
Room: RM 24
Location: TMS2021 Virtual

Session Chair: Hang Yu, Virginia Polytechnic Institute And State University; Ruigang Wang, Michigan State University

8:30 AM
Introductory Comments: Powder Materials for Energy Applications: Kathy Lu¹; ¹Virginia Polytechnic Institute and State University
    Introductory Comments

8:35 AM
Development of Gas Atomization Processes for Production of Passivated Calcium Powders: Jordan Tiarks¹; Dustin Hickman²; Trevor Riedemann¹; Iver Anderson¹; ¹Ames Laboratory; ²Iowa State University
    Aluminum/calcium composite conductors for overhead power transmission have been demonstrated on a laboratory scale to have improved performance characteristics compared with traditional conductors. The availability of sufficient fine (<100 μm) calcium powders needed for production of these conductors as wound cable is a major hindrance to up-scale development and verification of this technology. Production of calcium powder is complicated due to its low density and heat capacity and inability to form a passivated oxide surface layer, leaving it vulnerable to reaction with moisture in the air. Atomization processing developments to produce passivated, high-yield calcium powders requires the development of a new high-efficiency free-fall gas atomization die and design of an in-situ fluorination-based passivation methodology requiring a detailed understanding of intra-chamber particle cooling and passivation kinetics. Progress on the demonstration of newly developed production methods for fine calcium powders will be reported. Support from US-DOE-OE through Ames lab contract DE-AC02-07CH11358.

8:55 AM
Utilizing Solid-state Grain Alignment to Bias Abnormal Grain Growth in Strategically Designed Alnico Alloys: Emily Rinko¹; Timothy Prost²; Emma White³; Iver Anderson³; ¹Iowa State University; ²Ames Laboratory ; ³Ames Laboratory
    Alnico permanent magnets (PMs), a potential replacement PM for utilization in electric powered machines that contain rare earth (RE) PMs (e.g. interior PM motors in electric vehicles), need a large grained, <001> textured microstructure to have the best remanence and “squareness” of the second quadrant hysteresis loop, yielding the best energy product. Traditionally, this beneficial microstructure is obtained by directional solidification. However, to achieve this microstructure with a high-throughput fabrication approach, gas atomized, spherical alnico powder was compression molded, sintered, and solid-state grain aligned (SSGA). SSGA is a method to selectively bias the abnormal grain growth (AGG) close to the <001> direction via an applied load at high temperatures to yield large grained (>1 mm), <001> textured, powder-based alnico magnets. This presentation will discuss extending the SSGA method to strategically designed, high-coercivity alnico alloys, both Co-lean and full-Co alloys, and their resulting microstructures and properties. Work supported by USDOE.

9:15 AM  Invited
Wear Resistant Powder Materials for Energy Applications: Paul Prichard¹; Matthew Yao¹; ¹Kennametal Inc.
    A wide variety of materials are used in corrosion, erosion and wear protection for energy applications. The two important material classes of WC-Co grades and the Co-Cr Stellite^TM alloys are superior to the common stainless steels and Inconel alloys in many applications requiring combinations of corrosion, erosion and abrasion. The composition of Co-Cr alloys and WC-Co powders can be tailored to a variety of wear applications and aggressive environments. These versatile materials can develop significantly different properties as a result of processing such as casting, PTA, HVOF, P/M sinter or additive manufacturing. This presentation will discuss the effects of powder processing on key wear properties of WC-Co grades and Co-Cr Stellite^TM alloys.

9:45 AM
Conformal Coating of Powders by Physical Vapor Deposition: Jonathan Priedeman¹; Gregory Thompson¹; ¹University of Alabama
    Many powder based applications can be enhanced through the creation of a core shell structure. These applications include nuclear fuel elements, galvanic electrolyte cells, and even stabilized nanocrystalline alloys. The challenge resides in the ability to provide a uniform coating over the entirety of a spherical surface (powder). In this presentation, the ability to yield a fluidized bed of powder in a vacuum is discussed such that conventional two-dimensional physical vapor deposition can now provide coatings over a three-dimensional powder shape. In our approach, the powder agitation is provided by a piston-crank mechanism. Equations relating the dynamics, forces, and stresses of the system are developed and described in terms of scalability for the process. Examples of the coating technology is addressed with reference to coatings powders for nanocrystalline stabilized alloys.