Effect of WC-Ni Powder Composition and Preparation on Cold Spray Performance

Abstract

Toxic metal reduction is at the forefront of many design considerations today; additive manufacturing has the ability to combine materials in ways other traditional processes cannot and has the potential to offer unique solutions to reduce hazardous materials needed in manufacturing. Tungsten carbide (WC) has been used as a substitute in wear applications where toxic processes are traditionally utilized, but it can be difficult to deposit high-quality, hard and durable coatings. Additionally, there is a need to apply WC coatings on surfaces not feasible with the current processes. Cold spray, a solid-state directed powder deposition process, is effective at depositing carbides, though powders must be thoughtfully designed to achieve desired mechanical properties. In this study, WC was investigated as a hard chrome alternative for wear applications. Various blend ratios and preparation methods were evaluated as feedstock powder and then sprayed. Feedstock characteristics were compared to cold spray performance. Cold spray consolidations were evaluated for coating porosity and hardness. It was found that when powder make-up and composition were optimized, a high-hardness and low-porosity material was made that will contribute to the reduction in dependency of Cr in wear-facing components.

Postprocessing of tungsten carbide‐nickel preforms fabricated via binder jetting of sintered‐agglomerated powder

“…In general, hardness typically decreases with increasing nickel content and WC grain size. For a nickel wt % (17 wt.%) and carbide size (1.5 μm) similar to this study, previous literature measured hardness to be within the range of 60-62 Rockwell C. 35,56 The relatively higher hardness from the literature can be attributed to the lower porosity within their coupons, which were manufactured with alternative methods.…”

Effect of Gas Propellant Temperature on the Microstructure, Friction, and Wear Resistance of High-Pressure Cold Sprayed Zr702 Coatings on Al6061 Alloy

“…This can give a false representation of the coatings hardness, which would leave key information missing in the scientific analysis. Due to these facts, microhardness measurements were administered, similar to many other publications in CS and other thermal spray literatures [54][55][56][57][58][59][60][61][62][63][64]. In order to ensure repeatability, a total of 5 measurements under a 0.1 kgf were conducted and averaged.…”

Novel Characterization Techniques for Additive Manufacturing Powder Feedstock

“…While measuring composition is a way to differentiate between these two powders, not all additive manufacturing facilities or laboratories have the in-house capabilities to conduct such testing and utilizing external testing facilities can be time consuming and expensive. For this case study, the percent mass compacted metric is highlighted as a method for detecting slight differences in soft phase composition, which have been shown to correlate to cold spray properties like deposition efficiency [19]. This method allows for much faster iteration and quality control than slower, more expensive methods such as compositional analysis.…”

“…What is lacking with these methods, however, is that it is possible to cold spray powders of low flowability, that might not flow through either the Hall or the Carney funnel. In cold spray, this can be accomplished through the use of mechanical vibration with feeding [18][19][20].…”