Mark P. Everson

Evaluating rare earth element availability: a case with revolutionary demand from clean technologies.

The future availability of rare earth elements (REEs) is of concern due to monopolistic supply conditions, environmentally unsustainable mining practices, and rapid demand growth. We present an evaluation of potential future demand scenarios for REEs with a focus on the issue of comining. Many assumptions were made to simplify the analysis, but the scenarios identify some key variables that could affect future rare earth markets and market behavior. Increased use of wind energy and electric vehicles are key elements of a more sustainable future. However, since present technologies for electric vehicles and wind turbines rely heavily on dysprosium (Dy) and neodymium (Nd), in rare-earth magnets, future adoption of these technologies may result in large and disproportionate increases in the demand for these two elements. For this study, upper and lower bound usage projections for REE in these applications were developed to evaluate the state of future REE supply availability. In the absence of efficient reuse and recycling or the development of technologies which use lower amounts of Dy and Nd, following a path consistent with stabilization of atmospheric CO(2) at 450 ppm may lead to an increase of more than 700% and 2600% for Nd and Dy, respectively, over the next 25 years if the present REE needs in automotive and wind applications are representative of future needs.

Global Lithium Availability

There is disagreement on whether the supply of lithium is adequate to support a future global fleet of electric vehicles. We report a comprehensive analysis of the global lithium resources and compare it to an assessment of global lithium demand from 2010 to 2100 that assumes rapid and widespread adoption of electric vehicles. Recent estimates of global lithium resources have reached very different conclusions. We compiled data on 103 deposits containing lithium, with an emphasis on the 32 deposits that have a lithium resource of more than 100,000 tonnes each. For each deposit, data were compiled on its location, geologic type, dimensions, and content of lithium as well as current status of production where appropriate. Lithium demand was estimated under the assumption of two different growth scenarios for electric vehicles and other current battery and nonbattery applications. The global lithium resource is estimated to be about 39 Mt (million tonnes), whereas the highest demand scenario does not exceed 20 Mt for the period 2010 to 2100. We conclude that even with a rapid and widespread adoption of electric vehicles powered by lithium‐ion batteries, lithium resources are sufficient to support demand until at least the end of this century.

Nanotribological properties of organic boundary lubricants: Langmuir films versus self-assembled monolayers

Frictional characteristics of several types of boundary lubricants were tested using scanning probe microscopy (SPM). These include Langmuir monolayers of stearic acids (STA), their cadmium salts (STCd), self-assembling monolayers (SAMs) of alkylchlorsilanes, and complexes of STA with rigid naphthoylene benzimidazole (x-NBI) fragments. We observed that a Langmuir monolayer deposited on a silicon surface had a very low friction coefficient against a silicon nitride tip (about 0.01–0.05) but also low mechanical stability. SAMs were found to be much more stable but had the drawback of growth in the friction coefficient at high sliding velocities. Composite NBI/STA monolayers were much more stable and were not damaged by the highest normal load applied. The frictional behavior of different monolayers was analyzed in relation to their structural organization (the type of tethering to the surface and packing density). We introduced a figure of merit (FOM) parameter which allowed comparison of frictional properties of very different lubricant materials to those of the supporting substrate. For Langmuir monolayers the FOM increased strongly with surface packing density whereas for SAMs and x-NBI/STA complexes it possessed a maximum at surface densities in the range 3.5–4.5 molecules per nm2 . Because of the possibility of tailoring the surface packing density of aliphatic tails in the complexes, they are a promising alternative to both LB films and SAMs. For such composite monolayers, the surface packing density can be optimized to give a desired frictional behavior.

Use of a scanning probe microscope to measure marring mechanisms and microhardness of crosslinked coatings

A scanning probe microscope (SPM) was equipped with a high-modulus probe to indent coating surfaces when normal force is applied. A method for measuring microhardness with this probe is described. The high-modulus probe was also used to mar coating surfaces under controlled conditions by application of normal force plus lateral motion. Dimensions of the mars were measured by conventional scanning probe microscopy. The data were analyzed in terms of a “three response, two mechanism model” of marring in which three types of responses of polymeric materials: elastic, plastic deformation, and fracture, are measured. Of the three responses, only plastic deformation and fracture result in marring, and the two mechanisms can be quantified. A fourth quantity which combines plastic deformation and fracture is suggested as a method of comparing “micro mar resistance” of materials under specified conditions. Three crosslinked polymeric coatings were studied in detail. Two had hard crusts of material near their surfaces that responded quite differently than the bulk of the material.

Sustainable Mobility: Lithium, Rare Earth Elements, and Electric Vehicles

Recognition of the importance of climate change and energy security has led to interest in electrified vehicles. Electrified vehicles contain substantial amounts of lithium and rare earth elements. There has been concern that the supplies of lithium may not be sufficient to support the development of a large scale global fleet of electric vehicles. We conducted a comprehensive analysis of the global lithium resources and compared it to an assessment of global lithium demand from 2010 to 2100 that assumes rapid and widespread adoption of electrified vehicles. We show that that even with rapid and widespread adoption of electric vehicles powered by lithium-ion batteries lithium resources are sufficient to support demand until at least 2100. The future availability of rare earth elements (REEs) is of concern due to monopolistic supply conditions, environmentally unsustainable mining practices, and rapid demand growth. We evaluated potential future demand scenarios for REEs with a focus on the issue of co-mining. In the absence of efficient reuse and recycling or the development of technologies which use lower amounts of Dy and Nd, following a path consistent with stabilization of atmospheric CO2 at 450 ppm may lead to an increase in demand of more than 700 and 2,600 % for Nd and Dy, respectively, over the next 25 years.

New opportunities in automotive tribology

In this article we give an introduction to the field of automotive tribology as a guide to the following articles in this focus issue, and we review the recent application to automotive tribology of several molecular and microscopic level techniques. These include scanning force microscopy (SFM), nanohardness techniques, surface forces apparatus (SFA), computer modeling, vibrational spectroscopies, three UHV‐surface science techniques, and microcalorimetry. They are currently being used, in conjunction with more traditional techniques, to further both practical and fundamental knowledge of automotive tribological systems.

Strategic materials in the automobile: A comprehensive assessment of strategic and minor metals use in passenger cars and light trucks

A comprehensive component-level assessment of several strategic and minor metals (SaMMs), including copper, manganese, magnesium, nickel, tin, niobium, light rare earth elements (LREEs; lanthanum, cerium, praseodymium, neodymium, promethium, and samarium), cobalt, silver, tungsten, heavy rare earth elements (yttrium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium), and gold, use in the 2013 model year Ford Fiesta, Focus, Fusion, and F-150 is presented. Representative material contents in cars and light-duty trucks are estimated using comprehensive, component-level data reported by suppliers. Statistical methods are used to accommodate possible errors within the database and provide estimate bounds. Results indicate that there is a high degree of variability in SaMM use and that SaMMs are concentrated in electrical, drivetrain, and suspension subsystems. Results suggest that trucks contain greater amounts of aluminum, nickel, niobium, and silver and significantly greater amounts of magnesium, manganese, gold, and LREEs. We find tin and tungsten use in automobiles to be 3-5 times higher than reported by previous studies which have focused on automotive electronics. Automotive use of strategic and minor metals is substantial, with 2013 vehicle production in the United States, Canada, EU15, and Japan alone accounting for approximately 20% of global production of Mg and Ta and approximately 5% of Al, Cu, and Sn. The data and analysis provide researchers, recyclers, and decision-makers additional insight into the vehicle content of strategic and minor metals of current interest.

Automotive Applications of Materials Prepared by Ceramic Precursor and Sol-Gel Routes

The promise of new applications continues to drive research on ceramic precursor and sol-gel routes to materials preparation. These routes offer flexibility in the fabrication of materials in forms such as films, coatings, fibers, foams, and powders, etc. Our interest in ceramic precursors stems from their potential in the low cost fabrication of films. Such films can be employed in a variety of new automotive applications. In this article, we summarize our efforts to prepare soluble ceramic precursors and their conversion to group IV metal nitrides. A comparison of some properties of electrically conducting titanium nitride films prepared by dipcoat-fire cycle and low pressure CVD is presented. We also describe the fabrication of indium tin oxide films by a sol-gel process. These films are candidates in the low cost fabrication of electrically heatable catalyst devices.

Role of penetration twins in the morphological development of vapor-grown diamond films

Morphologies of vapor-deposited polycrystalline diamond films range from clean multimicron crystallites to nanocrystalline cauliflower nodules, depending on deposition conditions. While previous efforts to connect diamond film quality to growth conditions focus on competitive growth of nondiamond phases, we propose that twinning is a major controlling factor. We use a geometric construction to define growth conditions under which a given twin can outgrow and possibly bury the parent face on which it originated. We then show how the full spectrum of diamond crystallite shapes and film morphologies are explained in terms of penetration twins without reference to the actual mechanistics of diamond growth. This results in a reactor map that serves as a powerful tool in process development and control.