An automatic multi-precursor flow-type atomic layer deposition system.

Designs for two automated atomic layer deposition (ALD) flow reactors are presented, and their capabilities for coating additively manufactured (AM) metal prints are described. One instrument allows the coating of several AM parts in batches, while the other is useful for single part experiments. To demonstrate reactor capabilities, alumina (Al2O3) was deposited onto AM 316L stainless steel by dosing with water (H2O) vapor and trimethylaluminum (TMA) and purging with nitrogen gas (N2).

Chemical Solution Deposition of Protective ErO and YO Coatings onto Stainless Steel for Molten Metal Casting using Metal-Nitrate Precursors.

Chemical solution deposition (CSD) methods involving the thermal decomposition of 5.0 M Er(NO)·5HO and Y(NO)·6HO precursor solutions were employed to fabricate protective erbia and yttria coatings onto stainless steel (SS304/SS316) coupons. The two techniques tested were dip and spray coating, which were then compared to a commercial yttria spray (ZYP Coatings).

Growth and passivation of individual carbon nanoparticles by C2H2 addition at high temperatures: Dependence of growth rate and evolution on material and size.

Absolute kinetics for reactions of C2H2 with a series of ∼60 individual carbon nanoparticles (NPs) from graphite, graphene, graphene oxide, carbon black, diamond, and nano-onion feedstocks were measured for temperatures (TNP) ranging from 1200 to 1700 K. All the NPs were observed to gain mass by carbon addition under conditions that varied with feedstock but with large variations in initial growth rate. Long reaction periods were studied to allow the evolution of growth rates over time to be observed.

High-Temperature Oxidation of Single Carbon Nanoparticles: Dependence on the Surface Structure and Probing Real-Time Structural Evolution via Kinetics.

O oxidation and sublimation kinetics for >30 individual nanoparticles (NPs) of five different feedstocks (graphite, graphene oxide, carbon black, diamond, and nano-onion) were measured using single-NP mass spectrometry at temperatures () in the 1100-2900 K range. It was found that oxidation, studied in the 1200-1600 K range, is highly sensitive to the NP surface structure, with etching efficiencies (EE) varying by up to 4 orders of magnitude, whereas sublimation rates, significant only for ≥ ∼1700 K, varied by only a factor of ∼3. Its sensitivity to the NP surface structure makes O etching a good real-time structure probe, which was used to follow the evolution of the NP surface structures over time as they were either etched or annealed at high .

Sublimation Kinetics for Individual Graphite and Graphene Nanoparticles (NPs): NP-to-NP Variations and Evolving Structure-Kinetics and Structure-Emissivity Relationships.

A single nanoparticle (NP) mass spectrometry method was used to measure sublimation rates as a function of nanoparticle temperature (T) for sets of individual graphite and graphene NPs. Initially, the NP sublimation rates were ∼400 times faster than those for bulk graphite, and there were large NP-to-NP variations. Over time, the rates slowed substantially, though they remained well above the bulk rate.

Thermal emission spectroscopy for single nanoparticle temperature measurement: optical system design and calibration.

We discuss the design of an optical system that allows measurement of 600-1650 nm emission spectra for individual nanoparticles (NPs), laser-heated in an electrodynamic trap in controlled atmospheres. An approach to calibration of absolute intensity versus wavelength for very low emission intensities is discussed, and examples of NP graphite and carbon black spectra are used to illustrate the methodology.