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Pretreatment/Radionuclide Separations of Cs/Tc from Supernates

Description: Significant improvements have been made in ion exchange and solvent extraction materials and processes available for separation of the radionuclides cesium and technetium from both acid and alkaline waste solutions. New ion exchange materials and solvent extraction reagents are more selective for Cs over sodium and potassium than previous materials. The higher selectivity gives higher Cs capacity and improved separation processes. Technetium removal has been improved by new ion exchange resins, which have either improved capacity or easier elution. Several different crown ethers have been shown to extract pertechnetate ion selectively over other anions. Organic complexants in some waste solutions reduce pertechnetate ion and stabilize the reduced species. Selective oxidation allows conversion to pertechnetate without oxidation of the organic complexants.
Date: September 1, 1998
Creator: Thompson, M.C.
Partner: UNT Libraries Government Documents Department

Demonstration of the UREX Solvent Extraction Process with Dresden Reactor Fuel Solution

Description: A solvent extraction process to recover uranium and technetium from solutions of irradiated commercial reactor fuel while sending the plutonium to waste with the fission products and higher actinides was tested with actual fuel solution. Demonstration of the uranium extraction (UREX) process at baseline conditions showed that the process meets all goals for recovery and decontamination.
Date: November 1, 2002
Creator: Thompson, M.C.
Partner: UNT Libraries Government Documents Department

Purification Testing for HEU Blend Program

Description: The Savannah River Site (SRS) is working to dispose of the inventory of enriched uranium (EU) formerly used to make fuel for production reactors. The Tennessee Valley Authority (TVA) has agreed to take the material after blending the EU with either natural or depleted uranium to give a {sup 235}U concentration of 4.8 percent low-enriched uranium will be fabricated by a vendor into reactor fuel for use in TVA reactors. SRS prefers to blend the EU with existing depleted uranium (DU) solutions, however, the impurity concentrations in the DU and EU are so high that the blended material may not meet specifications agreed to with TVA. The principal non-radioactive impurities of concern are carbon, iron, phosphorus and sulfur. Neptunium and plutonium contamination levels are about 40 times greater than the desired specification. Tests of solvent extraction and fuel preparation with solutions of SRS uranium demonstrate that the UO{sub 2} prepared from these solutions will meet specifications for Fe, P and S, but may not meet the specifications for carbon. The reasons for carbon remaining in the oxide at such high levels is not fully understood, but may be overcome either by treatment of the solutions with activated carbon or heating the UO{sub 3} in air for a longer time during the calcination step of fuel preparation.Calculations of the expected removal of Np and Pu from the solutions show that the specification cannot be met with a single cycle of solvent extraction. The only way to ensure meeting the specification is dilution with natural U which contains no Np or Pu. Estimations of the decontamination from fission products and daughter products in the decay chains for the U isotopes show that the specification of 110 MEV Bq/g U can be met as long as the activities of the daughters of U- ...
Date: June 1, 1998
Creator: Thompson, M.C. & Pierce, R.A.
Partner: UNT Libraries Government Documents Department

Equilibrium distribution of uranyl nitrate between nitric acid and 7.5 vol % TBP

Description: The distribution of nitric acid and uranyl nitrate between aqueous solution and 7.5 vol percent tributyl phosphate in normal paraffin diluent was measured at 23, 45, and 60$sup 0$C. The data are consistent with behavior expected from theory and with previously published data. The data have been used to design a solvent extraction flowsheet for recovery of enriched uranium. (auth)
Date: October 1, 1975
Creator: Thompson, M.C.; Murphree, B.E. & Shankle, R.L.
Partner: UNT Libraries Government Documents Department

DISSOLUTION OF ZIRCALOY 2 CLAD UO2 COMMERCIAL REACTOR FUEL

Description: The primary goal of this investigation was to evaluate the effectiveness of the chop-leach process, with nitric acid solvent, to produce a nominally 300 g/L [U] and 1 M [H{sup +}] product solution. The results of this study show that this processing technique is appropriate for applications in which a low free acid and moderately high U content are desired. The 7.75 L of product solution, which was over 450 g/L in U, was successfully diluted to produce about 13 L of solvent extraction feed that was 302 g/L in U with a [H{sup +}] in the range 0.8-1.2 M. A secondary goal was to test the effectiveness of this treatment for the removal of actinides from Zircaloy cladding to produce a low-level radioactive waste (LLW) cladding product. Analysis of the cladding shows that actinides are present in the cladding at a concentration of about 5000 {eta}Ci/g, which is about 50 times greater than the acceptable transuranium element limit in low level radioactive waste. It appears that the concentration of nitric acid used for this dissolution study (initial concentration 4 M, with 10 M added as the dissolution proceeded) was inadequate to completely digest the UO{sub 2} present in the spent fuel. The mass of insoluble material collected from the initial treatments with nitric acid, 340 g, was much higher than expected, and analysis of this insoluble residue showed that it contained at least 200 g U.
Date: August 7, 2009
Creator: Kessinger, G. & Thompson, M.
Partner: UNT Libraries Government Documents Department

SHARING AND DEPLOYING INNOVATIVE INFORMATION TECHNOLOGY SOLUTIONS TO MANAGE WASTE ACROSS THE DOE COMPLEX

Description: There has been a need for a faster and cheaper deployment model for information technology (IT) solutions to address waste management needs at US Department of Energy (DOE) complex sites for years. Budget constraints, challenges in deploying new technologies, frequent travel, and increased job demands for existing employees have prevented IT organizations from staying abreast of new technologies or deploying them quickly. Despite such challenges, IT organizations have added significant value to waste management handling through better worker safety, tracking, characterization, and disposition at DOE complex sites. Systems developed for site-specific missions have broad applicability to waste management challenges and in many cases have been expanded to meet other waste missions. Radio frequency identification (RFID) and global positioning satellite (GPS)-enabled solutions have reduced the risk of radiation exposure and safety risks. New web-based and mobile applications have enabled precision characterization and control of nuclear materials. These solutions have also improved operational efficiencies and shortened schedules, reduced cost, and improved regulatory compliance. Collaboration between US Department of Energy (DOE) complex sites is improving time to delivery and cost efficiencies for waste management missions with new information technologies (IT) such as wireless computing, global positioning satellite (GPS), and radio frequency identification (RFID). Integrated solutions developed at separate DOE complex sites by new technology Centers of Excellence (CoE) have increased material control and accountability, worker safety, and environmental sustainability. CoEs offer other DOE sister sites significant cost and time savings by leveraging their technology expertise in project scoping, implementation, and ongoing operations.
Date: January 31, 2011
Creator: Crolley, R. & Thompson, M.
Partner: UNT Libraries Government Documents Department

ENHANCED CHEMICAL CLEANING OF SRS WASTE TANKS TO IMPROVE ACTINIDE SOLUBILITY

Description: Processes for the removal of residual sludge from SRS waste tanks have historically used solutions containing up to 0.9 M oxalic acid to dissolve the remaining material following sludge removal. The selection of this process was based on a comparison of a number of studies performed to evaluate the dissolution of residual sludge. In contrast, the dissolution of the actinide mass, which represents a very small fraction of the waste, has not been extensively studied. The Pu, Np, and Am in the sludge is reported to be present as hydrated and crystalline oxides. To identify aqueous solutions which have the potential to increase the solubility of the actinides, the alkaline and mildly acidic test solutions shown below were selected as candidates for use in a series of solubility experiments. The efficiency of the solutions in solubilizing the actinides was evaluated using a simulated sludge prepared by neutralizing a HNO{sub 3} solution containing Pu, Np, and Am. The hydroxide concentration was adjusted to a 1.2 M excess and the solids were allowed to age for several weeks prior to starting the experiments. The sludge was washed with 0.01 M NaOH to prepare the solids for use. Following the addition of an equal portion of the solids to each test solution, the concentrations of Pu, Np, and Am were measured as a function of time over a 792 h (33 day) period to provide a direct comparison of the efficiency of each solution in solubilizing the actinide elements. Although the composition of the sludge was limited to the hydrated actinide oxides (and did not contain other components of demonstrated importance), the results of the study provides guidance for the selection of solutions which should be evaluated in subsequent tests with a more realistic surrogate sludge and actual tank waste.
Date: September 20, 2011
Creator: Rudisill, T. & Thompson, M.
Partner: UNT Libraries Government Documents Department

Flowsheet for coprocessing uranium and plutonium

Description: A coprocessing solvent extraction flowsheet for recovering and purifying LWR fuels has been altered to achieve partial partioning of uranium and plutonium to eliminate streams with pure plutonium. Partial partitioning has been demonstrated in the laboratory with simulated feeds and irradiated LWR fuel solutions. Hydroxylamine nitrate was the reductant in these tests. Plutonium was concentrated by factors of 6 to 27.4. Tests have shown that 1 to 2 plutonium atoms are reduced for each hydroxylamine molecule consumed. Nitrite interferes with the reduction of plutonium, unless the hydroxylamine concentration is increased. 12 tables, 11 figures.
Date: January 1, 1979
Creator: Statton, M.A. & Thompson, M.C.
Partner: UNT Libraries Government Documents Department

Phase II environmental geophysics at J-Field, Aberdeen Proving Ground, Maryland

Description: Geophysical studies were conducted at eight sites on the tip of Gunpowder Neck (J-Field) in the Edgewood Area of Aberdeen Proving Ground, Maryland. The results of the studies were used to delineate the extent of three former burning pits and help determine the necessity of further investigation at five potential areas of concern (PAOCs). Intensive investigations were performed at the three former burning pits and two of the PAOCs by using electromagnetic (EM-31 and EM-61), total field magnetometry, and ground-penetrating radar geophysical techniques. The successful integration of the four data sets characterized the extent, the approximate depth and nature of fill material, and the location of metallic debris at the three former burning pits. At the two PAOC sites that were intensively investigated, no continuous areas of metallic debris, indicating organized burials, were present. Less extensive exploratory profiles conducted at three other PAOC sites indicated the presence of buried metal objects, but they were inconclusive in defining the nature and extent of buried materials.
Date: September 1995
Creator: Davies, B. E.; Thompson, M. D. & Yuen, C. R.
Partner: UNT Libraries Government Documents Department

Geophysical investigations at the engine test area of Camp Crowder, Missouri.

Description: Camp Crowder, which is located south of Neosho, Missouri, is currently a Missouri Army National Guard training facility (Figure 1). The site was established as Camp Crowder during World War II and served as a U.S. Army Signal Corps Replacement Training Center. During the height of the war, Camp Crowder occupied an area of about 43,000 acres, which is much larger than its current dimensions. From 1957 to 1972, a portion of Camp Crowder was operated for the federal government as a rocket and jet engine manufacturing plant and testing area. One testing area was known as the ETA (ETA) and remains a part of Camp Crowder (Figure 2). The other test area was termed the Components Test Area (CTA) and is now privately owned. Recent site investigations have indicated that contamination is present in both the soil and groundwater at the ETA and the CTA (Rust 1993). Dye tracer studies conducted on and near Camp Crowder show that the site provides groundwater recharge to several nearby springs (Vandike and Brookshire 1996). Photogeologic analysis by Frano (1999) indicates the presence of several lineament sets, which are likely to represent fracture systems in the underlying bedrock. Argonne National Laboratory (ANL) has been tasked to identify and apply appropriate geophysical techniques that will assist in the development of a more thorough understanding of the complex interrelationships between groundwater flow and geologic structure at the Camp Crowder site. The specific goal of this effort is to locate zones for preferential groundwater and/or contaminant migration.
Date: August 11, 2000
Creator: Miller, S. F.; Thompson, M. D.; Cooper, J. M. & Mandell, W.
Partner: UNT Libraries Government Documents Department

Theoretical study of ion/macrocycle interactions using both hybrid quantum mechanical-molecular mechanical and ab initio methods

Description: Synthetic macrocycles have drawn much experimental and theoretical interest since Pederson first synthesized the crown-ether 18-crown-6 (18c6) in 1967. Crown-ethers show a remarkable range of specificity for a wide variety of cations that depends, in part, on the size of the ether, the type of donor atoms (e.g. oxygen, nitrogen, sulfur), and the polarity of the solvent. Crown-ethers and related macrocycles are of particular interest to research efforts in chemical separations applied to environmental remediation. For example, at the Hanford nuclear facility {sup 9O}Sr{sup 2+} and {sup 137}Cs{sup +} are two major generators of heat which complicate the disposal of nuclear waste. One example of the use of crown-ethers for radionuclide separation is the Strontium Extraction (SREX) process which uses di-t-butylcyclohexano-18-crown-6 for recovering {sup 9O}Sr{sup 2+} from acidic solution. A more thorough understanding of fundamental interactions of cation/crown-ether solution chemistry may provide the basis for rational design of new ligands useful in the separation of these and other radionuclides from radionuclide-containing waste streams at hazardous waste storage facilities. There is also a growing interest in the use of crown-ethers, cryptands, and other ligands for use in chemical sensors. Specifically, fluoroionophores, which consisting of a fluorophore (e.g. dye-molecule) linked to an ionophore (e.g. crown-ether), exhibit measurable changes in the photophysical properties of the fluorophore upon ion binding by the ionophore. Fluoroionophores would be useful for monitoring ground-water aquifers and industrial effluent streams for low-levels of hazardous radionuclides and other toxic metals.
Date: August 1, 1995
Creator: Thompson, M.A.; Glendening, E.D.; Feller, D. & Kendall, R.
Partner: UNT Libraries Government Documents Department

Bay Ridge Gardens - Mixed-Humid Affordable Multifamily Housing Deep Energy Retrofit

Description: Under this project, Newport Partners (as part of the BA-PIRC research team) evaluated the installation, measured performance, and cost-effectiveness of efficiency upgrade measures for a tenant-in-place DER at the Bay Ridge multifamily (MF) development in Annapolis, Maryland. The design and construction phase of the Bay Ridge project was completed in August 2012. This report summarizes system commissioning, short-term test results, utility bill data analysis, and analysis of real-time data collected over a one-year period after the retrofit was complete. The Bay Ridge project is comprised of a 'base scope' retrofit which was estimated to achieve a 30%+ savings (relative to pre-retrofit) on 186 apartments, and a 'DER scope' which was estimated to achieve 50% savings (relative to pre-retrofit) on a 12-unit building. The base scope was applied to the entire apartment complex, except for one 12-unit building which underwent the DER scope. A wide range of efficiency measures was applied to pursue this savings target for the DER building, including improvements/replacements of mechanical equipment and distribution systems, appliances, lighting and lighting controls, the building envelope, hot water conservation measures, and resident education. The results of this research build upon the current body of knowledge of multifamily retrofits. Towards this end, the research team has collected and generated data on the selection of measures, their estimated performance, their measured performance, and risk factors and their impact on potential measures.
Date: August 1, 2013
Creator: Lyons, J.; Moore, M. & Thompson, M.
Partner: UNT Libraries Government Documents Department

Zero-tension lysimeters: An improved design to monitor colloid-facilitated contaminant transport in the vadose zone

Description: There is increasing evidence that mobile colloids facilitate the long-distance transport of contaminants. The mobility of fine particles and macromolecules has been linked to the movement of actinides, organic contaminants, and heavy metals through soil. Direct evidence for colloid mobility includes the presence of humic materials in deep aquifers as well as coatings of accumulated clay, organic matter, or sesquioxides on particle or aggregate surfaces in subsoil horizons of many soils. The potential for colloid-facilitated transport of contaminants from hazardous-waste sites requires adequate monitoring before, during, and after in-situ remediation treatments. Zero-tension lysimeters (ZTLs) are especially appropriate for sampling water as it moves through saturated soil, although some unsaturated flow events may be sampled as well. Because no ceramic barrier or fiberglass wick is involved to maintain tension on the water (as is the case with other lysimeters), particles suspended in the water as well as dissolved species may be sampled with ZTLs. In this report, a ZTL design is proposed that is more suitable for monitoring colloid-facilitated contaminant migration. The improved design consists of a cylinder made of polycarbonate or polytetrafluoroethylene (PTFE) that is placed below undisturbed soil material. In many soils, a hydraulically powered tube may be used to extract an undisturbed core of soil before placement of the lysimeter. In those cases, the design has significant advantages over conventional designs with respect to simplicity and speed of installation. Therefore, it will allow colloid-facilitated transport of contaminants to be monitored at more locations at a given site.
Date: April 24, 1995
Creator: Thompson, M.L.; Scharf, R.L. & Shang, C.
Partner: UNT Libraries Government Documents Department

TAILORING INORGANIC SORBENTS FOR SRS STRONTIUM AND ACTINIDE SEPARATIONS: OPTIMIZED MONOSODIUM TITANATEPHASE II INTERIM REPORT FOR EXTERNAL RELEASE

Description: This document provides an interim summary report of Phase II testing activities for the development of a modified monosodium titanate (MST) that exhibits improved strontium and actinide removal characteristics compared to the baseline MST materials. The activities included determining the key synthesis conditions for preparation of the modified MST, preparation of the modified MST at a larger laboratory scale, demonstration of the strontium and actinide removal characteristics with actual tank waste supernate and characterization of the modified MST. Key findings and conclusions include the following: (1) Samples of the modified MST prepared by Method 2 and Method 3 exhibited the best combination of strontium and actinide removal. (2) We selected Method 3 to scale up and test performance with actual waste solution. (3) We successfully prepared three batches of the modified MST using the Method 3 procedure at a 25-gram scale. (4) Performance tests indicated successful scale-up to the 25-gram scale with excellent performance and reproducibility among each of the three batches. For example, the plutonium decontamination factors (6-hour contact time) for the modified MST samples averaged 13 times higher than that of the baseline MST sample at half the sorbent concentration (0.2 g L{sup -1} for modified MST versus 0.4 g L{sup -1} for baseline MST). (5) Performance tests with actual waste supernate demonstrated that the modified MST exhibited better strontium and plutonium removal performance than that of the baseline MST. For example, the decontamination factors for the modified MST measured 2.6 times higher for strontium and between 5.2 to 11 times higher for plutonium compared to the baseline MST sample. The modified MST did not exhibit improved neptunium removal performance over that of the baseline MST. (6) Two strikes of the modified MST provided increased removal of strontium and actinides from actual waste compared to a single strike. ...
Date: August 31, 2006
Creator: Hobbs, D; Michael Poirier, M; Mark Barnes, M & Mary Thompson, M
Partner: UNT Libraries Government Documents Department

GUIDE TO CALCULATING TRANSPORT EFFICIENCY OF AEROSOLS IN OCCUPATIONAL AIR SAMPLING SYSTEMS

Description: This report will present hand calculations for transport efficiency based on aspiration efficiency and particle deposition losses. Because the hand calculations become long and tedious, especially for lognormal distributions of aerosols, an R script (R 2011) will be provided for each element examined. Calculations are provided for the most common elements in a remote air sampling system, including a thin-walled probe in ambient air, straight tubing, bends and a sample housing. One popular alternative approach would be to put such calculations in a spreadsheet, a thorough version of which is shared by Paul Baron via the Aerocalc spreadsheet (Baron 2012). To provide greater transparency and to avoid common spreadsheet vulnerabilities to errors (Burns 2012), this report uses R. The particle size is based on the concept of activity median aerodynamic diameter (AMAD). The AMAD is a particle size in an aerosol where fifty percent of the activity in the aerosol is associated with particles of aerodynamic diameter greater than the AMAD. This concept allows for the simplification of transport efficiency calculations where all particles are treated as spheres with the density of water (1 g�cm-3). In reality, particle densities depend on the actual material involved. Particle geometries can be very complicated. Dynamic shape factors are provided by Hinds (Hinds 1999). Some example factors are: 1.00 for a sphere, 1.08 for a cube, 1.68 for a long cylinder (10 times as long as it is wide), 1.05 to 1.11 for bituminous coal, 1.57 for sand and 1.88 for talc. Revision 1 is made to correct an error in the original version of this report. The particle distributions are based on activity weighting of particles rather than based on the number of particles of each size. Therefore, the mass correction made in the original version is removed from the text and the ...
Date: November 12, 2013
Creator: Hogue, M.; Hadlock, D.; Thompson, M. & Farfan, E.
Partner: UNT Libraries Government Documents Department

Cesium Removal from R-Reactor Building Disassembly Basin Using 3MEmpore Web-Membrane Filter Technology

Description: A seven-day demonstration of the use of 3M Empore membrane filter loaded with ion exchange material (potassium cobalt hexacynoferrate (CoHex)) for cesium uptake was completed at the R-Disassembly Basin. The main goal of the demonstration was to evaluate the ability of the Process Absorber Development unit (PADU), a water pre-filtration /CoHex configuration on a skid, to remove cesium from R-Disassembly Basin at a linear processing flow rate of 22.71 liters (6 gallons) per minute.
Date: June 25, 1998
Creator: Oji, L.N.; Thompson, M.C.; Peterson, K.; May, C. & Kafka, T.M.
Partner: UNT Libraries Government Documents Department

A high-resolution, four-band SAR testbed with real-time image formation

Description: This paper describes the Twin-Otter SAR Testbed developed at Sandia National Laboratories. This SAR is a flexible, adaptable testbed capable of operation on four frequency bands: Ka, Ku, X, and VHF/UHF bands. The SAR features real-time image formation at fine resolution in spotlight and stripmap modes. High-quality images are formed in real time using the overlapped subaperture (OSA) image-formation and phase gradient autofocus (PGA) algorithms.
Date: March 1, 1996
Creator: Walker, B.; Sander, G.; Thompson, M.; Burns, B.; Fellerhoff, R. & Dubbert, D.
Partner: UNT Libraries Government Documents Department

HANFORD GROUNDWATER REMEDIATION

Description: By 1990 nearly 50 years of producing plutonium put approximately 1.70E + 12 liters (450 billion gallons) of liquid wastes into the soil of the 1,518-square kilometer (586-square mile) Hanford Site in southeast Washington State. The liquid releases consisted of chemicals used in laboratory experiments, manufacturing and rinsing uranium fuel, dissolving that fuel after irradiation in Hanford's nuclear reactors, and in liquefying plutonium scraps needed to feed other plutonium-processing operations. Chemicals were also added to the water used to cool Hanford's reactors to prevent corrosion in the reactor tubes. In addition, water and acid rinses were used to clean plutonium deposits from piping in Hanford's large radiochemical facilities. All of these chemicals became contaminated with radionuclides. As Hanford raced to help win World War II, and then raced to produce materials for the Cold War, these radioactive liquid wastes were released to the Site's sandy soils. Early scientific experiments seemed to show that the most highly radioactive components of these liquids would bind to the soil just below the surface of the land, thus posing no threat to groundwater. Other experiments predicted that the water containing most radionuclides would take hundreds of years to seep into groundwater, decaying (or losing) most of its radioactivity before reaching the groundwater or subsequently flowing into the Columbia River, although it was known that some contaminants like tritium would move quickly. Evidence today, however, shows that many contaminants have reached the Site's groundwater and the Columbia River, with more on its way. Over 259 square kilometers (100 square miles) of groundwater at Hanford have contaminant levels above drinking-water standards. Also key to successfully cleaning up the Site is providing information resources and public-involvement opportunities to Hanford's stakeholders. This large, passionate, diverse, and geographically dispersed community is united in its desire to protect the Columbia ...
Date: February 1, 2006
Creator: CHARBONEAU, B; THOMPSON, M; WILDE, R.; FORD, B. & GERBER, M.S.
Partner: UNT Libraries Government Documents Department

Interim progress report addendun - environmental geophysics: Building E5032 decommissioning, Aberdeen Proving Ground, January 1994 resurvey

Description: Geophysical surveying around Building E5032 using three new continuously recording geophysical instruments - two types of electromagnetic induction instruments and a cesium vapor magnetometer that were unavailable at the time of the original survey - has provided additional information for defining the location of buried debris, vaults, tanks, and the drainage/sump system near the building. The dominant geophysical signature around Building E5032 consists of a complex pattern of linear magnetic, electrical-conductivity, and electromagnetic field anomalies that appear to be associated with drainage/sewer systems, ditches, past railway activity, the location for Building T5033 (old number 99A), and the probable location of Building 91. Integrated analysis of data acquired using the three techniques, plus a review of the existing ground-penetrating-radar data, allow a more thorough definition of the sources for the observed anomalies.
Date: December 1, 1994
Creator: Thompson, M.D.; McGinnis, L.D.; Benson, M.A.; Borden, H.M. & Padar, C.A.
Partner: UNT Libraries Government Documents Department

Use of pulsed high power ion beams to enhance tribological properties of stainless steel, Ti, and Al

Description: Enhanced tribological properties have been observed after treatment with pulsed high power ion beams, which results in rapid melting and resolidification of the surface. The authors have treated and tested 440C martensitic stainless steel (Fe-17 Cr-1 C). Ti and Al samples were sputter coated and ion beam treated to produce surface alloying. The samples were treated at the RHEPP-I facility at Sandia National Laboratories (0.5 MV, 0.5--1 {micro}s at sample location, <10 J/cm{sup 2}, 1--5 {micro}m ion range). They have observed a reduction in size of second phase particles and other microstructural changes in 440C steel. The hardness of treated 440C increases with ion beam fluence and a maximum hardness increase of a factor of 5 is obtained. Low wear rates are observed in wear tested of treated 440C steel. Surface alloyed Ti-Pt layers show improvements in hardness up to a factor of 3 over untreated Ti, and surface alloys of Al-Si result in a hardness increase of a factor of two over untreated Al. Both surface alloys show increased durability in wear testing. Rutherford Backscattering (RBS) measurements show overlayer mixing to the depth of the melted layer. X-ray Diffraction (XRD) and TEM confirm the existence of metastable states within the treated layer. Treated layer depths have been measured from 1--10 {micro}m.
Date: April 1, 1998
Creator: Senft, D.C.; Renk, T.J.; Dugger, M.T.; Grabowski, K.S. & Thompson, M.O.
Partner: UNT Libraries Government Documents Department

The electrochemical behavior of Ti and Ti alloys subjected to pulsed ion beam surface treatment

Description: Pulsed high-energy ion beams have been used to thermally treat Ti and Ti alloy surfaces to alter the electrochemical response. Two regimes have been explored: rapid melt and resolidification, and ion beam mixing. In this report, results from initial studies are presented exploring effect of these two regimes on the electrochemical behavior of Ti and Ti alloys.
Date: October 1, 1996
Creator: Sorensen, N.R.; Buchheit, R.G.; Renk, T.R.; Grabowski, K.S. & Thompson, M.O.
Partner: UNT Libraries Government Documents Department