Mirror Polishing Research Articles

Lightweight structure and unequal length flexible support design of a 1.3×1.2 m rectangular, horizontally supported mirror

A lightweight rectangular mirror designed for a space telescope features a lightweight structure and an innovative unequal length flexible support design. This design incorporates a three-point back support structure, which maintains the surface accuracy of the mirror assembly in a horizontal optical testing layout. The topology optimization design method is applied for the lightweight design of a SiC mirror. According to the principle that optimal gravity surface accuracy of the mirror is achieved when the pivot center of the flexible support coincides with the neutral plane of the mirror, an unequal length flexible support scheme is proposed. Furthermore, a “neck-shrinking” flexible support structure is designed to enhance the comprehensive surface quality of the mirror assembly, achieving better than λ/140 (RMS = 4.5 nm, λ=632.8nm). Following the completion of mirror polishing, an optical test system is established. The test results confirm that the surface shape accuracy satisfies the requirements of the design index. In addition, the mechanical design has been corroborated through dynamic testing.

Synthesis and characterization of Fe3O4@SiO2 core-shell nanoparticles for mirror and efficient magnetic compound fluid polishing of TC4 titanium alloy

To fully investigate the polishing performance of the Fe3O4@SiO2 core–shell abrasive for TC4 titanium alloy plate and solve the problem of uneven distribution of abrasive particles in magnetic compound fluid polishing (MCFP) and obtain ultra-smooth titanium alloy surface. In this paper, the functional Fe3O4@SiO2 core–shell abrasives were prepared and characterized by XRD, FTIR, VSM and TEM to demonstrate the successful encapsulation of SiO2 in Fe3O4 first. Second, a new polishing device was built to perform polishing experiments. Four different fractions of Magnetic compound fluid (MCF) were configured and utilized in polishing experiments for MCFP of TC4 titanium alloy to verify the polishing properties. Finally, the contact model between abrasive particles and workpiece is established and the material removal mechanism is discussed. The results show that SiO2 was successfully coated on Fe3O4. The polishing results show that the MCF containing the core–shell structure had the best polishing effect. The surface roughness Ra decreased from 0.201 μm to 0.025 μm after 20 min of polishing. The surface roughness of TC4 titanium alloy with an initial roughness Sa of 0.248 μm is reduced to 0.023 μm after polishing by Fe3O4@SiO2 core–shell abrasive. It is shown that the application of core–shell abrasive to process titanium alloys can obtain smooth and defect-free surfaces with good polishing performance. The surface quality of titanium alloy can be improved effectively by using core–shell abrasive, and a new idea for polishing titanium alloy is proposed. This study plays an important role in solving the problem of uneven particle distribution in MCFP. These results pave the way for further research into the application of core–shell abrasives in precision machining and expand the application scope of particles with core–shell structure.

Efficient full-aperture mirror polishing method with variable orbital radius in computer-controlled optical surfacing

Optical systems in astronomy have extremely high requirements on the full-aperture surface precision and fabrication efficiency of aspherical mirrors. However, the current full-aperture optics fabrication method suffers from both fabrication and computation inefficiency. The former is caused by the isolated polishing strategy for the inner and edge regions of the mirror with different tools, while the latter is caused by the global computation strategy for the two regions. In this paper, a full-aperture mirror polishing method with the reversed strategy is proposed to solve this problem. Firstly, the dwell time of inner/edge regions are respectively calculated by the deconvolution method and the linear equations method based on the space-variant tool influence function. Therefore, both the computation cost and the edge polishing error can be reduced. Then, a fused tool path is developed to achieve variable orbital radius in the inner/edge region so the full aperture can be polished in one round. Simulations and experiments using a SiC aspherical mirror and large segmented mirrors demonstrate that the surface error can converge quickly in the full aperture. As a consequence, the full-aperture fabrication accuracy and efficiency can be greatly improved through the proposed method.

Effect of substrate pretreatments on the structure and properties of AlTiN coatings deposited on TiCN-based cermets

Four different pretreatments (mirror polishing, grinding, sandblasting and acid washing) were performed on TiCN-based cermets substrates. Subsequently, AlTiN coatings were deposited on the four differently pretreated substrates by means of arc ion plating. The microstructure of AlTiN coatings were studied by scanning electron microscope and X-ray diffractometer. The results showed that the AlTiN coatings on differently pretreated substrates exhibited columnar structure with (200) preferred orientation. The columnar crystal of coatings coarsened with the increase of substrate surface roughness under the four pretreatments, and the thickness of the coatings increased. Scratch test showed that the adhesion strength of the AlTiN coating on the pickled substrate increased by 46.8% in comparison with that on the polished substrate. Wear test showed that the average friction coefficient of AlTiN coatings increased gradually with the increase of substrate surface roughness under the four substrate pretreatments. The AlTiN coating on the pickled substrate had the largest grain size and many voids. Therefore, the hardness was low and the wear resistance was poor. The AlTiN coating on the sandblasted substrate had the smallest grain size, and accordingly had high hardness and the best wear resistance.

Distinctive Effects of Surface Roughness and Ions Release on the Bacterial Adhesion and Inactivation of Textured Copper Oxide Surfaces

In this manuscript, we studied the effect of additive manufacturing pretreatment on bacterial adhesion and inactivation on copper-based interfaces. Sandblasting, mirror polishing and Surface Mechanical Attrition Treatment (SMAT) at high or low energies have been employed to modify the substrate’s (316L stainless steel) roughness. The pretreated substrates were coated with thin copper films using magnetron sputtering. The thin copper films’ composition and antibacterial activities were first optimized by being deposited on an Si wafer. We showed that the surface roughness profile influenced bacterial adhesion in the dark. Bacterial inactivation was monitored under indoor light. Stereomicroscopy imaging showed live/dead bacterial cells on the coated substrates. Scanning electron microscopy (SEM) showed homogeneous coating growths of copper with a columnar texture. The chemical composition of the deposited Cu thin films was carried out by Energy Dispersive X-ray Spectroscopy (EDX) and showed a uniform distribution of copper and oxygen, revealing the formation of copper oxides (CuxO). The oxygen content of the sputtered films varied from 7.8 to 25%, justifying the semi-conductor behavior of the thin films under indoor light. The crystallographic structure of the sputtered thin films was investigated using X-ray diffraction (XRD), showing the cubic Cu peaks and characteristic peaks of Cu2O. The Cu peaks at 2θ values of 43.28°, 50.40° and 74.81° were attributed to the (111), (200) and (220) planes, respectively. The use of genetically modified bacteria (without porins) allowed the rationalization of the predominant effect of the extracellular bacterial inactivation compared to that of intracellular bacterial inactivation through ion release and diffusion.

Mechanical properties–translucency–microstructure relationships in commercial monolayer and multilayer monolithic zirconia ceramics

ObjectivesTo evaluate the phase composition, microstructure, optical properties and mechanical properties of eight commercially available multilayer and monolayer monolithic dental zirconias. MethodsFive commercial 3Y-TZP (GC ST, GC HT [GC, Tokyo Japan]; Katana ML, Katana HT [Kuraray Noritake] and Lava Plus [3M Oral Care]) and three Y-PSZ (Katana STML, Katana UTML [Kuraray Noritake]; GC UHT [GC, Tokyo Japan]) zirconia ceramic grades were cut in plate-shaped specimens, sintered according to the manufacturer’s instructions and mirror polished. The zirconia chemical composition was determined using X-ray fluorescence (XRF), phase composition was characterized using X-ray diffraction (XRD), while the grain size was measured using scanning electron microscopy (SEM). The translucency Parameter (TP) and Contrast Ratio (CR) were measured with a spectrophotometer (n = 10/group). The indentation fracture toughness (n = 10), Vickers hardness (n = 10) and biaxial strength (n = 20) of the sintered ceramics were assessed. The stress distribution during biaxial testing was assessed by Finite element analysis (FEA). Statistical analysis involved one-way ANOVA and post-hoc Tukey’s HSD test and Pearson correlation test (α = 0.05). ResultsFEA showed that the stress distribution in plate shape specimens was the same as for disks, rationalizing the use of plates for biaxial strength testing. As expected, higher quantities of Y2O3 were related to a higher cubic ZrO2 phase content and lower tetragonality t-ZrO2, which improved translucency but diminished flexural strength and toughness. While there was no significant correlation between grain size and other material properties, addition of pigments to the zirconia grade statistically negatively affected hardness. ConclusionEven though an improvement in strength and translucency could be recorded for the last Y-TZP generation, future research still needs to strive for combined improvement of optical properties and mechanical reliability of zirconia ceramics.

The effectiveness of ornamental building materials (tiles) for retrospective thermoluminescence dosimetry

Like many other decorative building materials, tiles are one of the most precious ornamental ingredients for making a lucrative building image. It not only offers beauty and luxury but also added value by protecting/monitoring ionizing radiation. In this study, the utmost regular use of seven varieties of tile samples has been considered for retrospective thermoluminescence dosimetry. To observe the potentials of tiles for retrospective dosimetry, the major thermoluminescence properties (such as dose-response, energy dependence, self-sensitivity, relative sensitivity, glow curves, repeatability, fading, and also effective atomic number) has been investigated following the annealing - irradiation – readout cycles. Making an allowance for the various TL parameters, White Horse (Mirror Polish) tiles demonstrate suitability to be used as emergency TL dosimeter in 0.5–100 Gy dose array. Comparing the values of Zeff of these numerous tiles’ samples (11.6–12.7) with TLD-200 (Zeff = 16.3), it is to be noted that tiles can be used as a suitable material for environmental radiation dosimetry. The thermoluminescent characteristics of tiles in the dose limit from 0.5 Gy to 100 Gy are reported here for the first time.

Classification and Properties of Dental Zirconia as Implant Fixtures and Superstructures.

Various types of zirconia are widely used for the fabrication of dental implant superstructures and fixtures. Zirconia–alumina composites, such as ATZ and NanoZR, are adequate for implant fixtures because they have excellent mechanical strength in spite of insufficient esthetic properties. On the other hand, yttria-stabilized zirconia has been used for implant superstructures because of sufficient esthetic properties. They are classified to 12 types with yttria content, monochromatic/polychromatic, uniform/hybrid composition, and monolayer/multilayer. Zirconia with a higher yttria content has higher translucency and lower mechanical strength. Fracture strength of superstructures strongly depends on the strength on the occlusal contact region. It suggests that adequate zirconia should be selected as the superstructure crown, depending on whether strength or esthetics is prioritized. Low temperature degradation of zirconia decreases with yttria content, but even 3Y zirconia has a sufficient durability in oral condition. Although zirconia is the hardest dental materials, zirconia restorative rarely subjects the antagonist teeth to occlusal wear when it is mirror polished. Furthermore, zirconia has less bacterial adhesion and better soft tissue adhesion when it is mirror polished. This indicates that zirconia has advantageous for implant superstructures. As implant fixtures, zirconia is required for surface modification to obtain osseointegration to bone. Various surface treatments, such as roughening, surface activation, and coating, has been developed and improved. It is concluded that an adequately selected zirconia is a suitable material as implant superstructures and fixtures because of mechanically, esthetically, and biologically excellent properties.

Explicit dynamic modeling with joint friction and coupling analysis of a 5-DOF hybrid polishing robot

Aiming at a 5-DOF hybrid optical mirror polishing robot, the explicit dynamic model considering the joint friction is established and the inertia coupling distribution is studied. Firstly, the kinematics of the manipulator is solved based on closed-loop vector method, and the dynamic model is established with Newton-Euler method based on the force analysis of manipulator components. Secondly, the kinematic parameters of the reference point of the moving platform are selected as the intermediate variables, and the explicit dynamic model of the parallel manipulator is obtained by parameters substitution considering the friction effects of spherical joints, universal joints and ball screws. Finally, on the basis of the dynamic model, the inertia coupling strength evaluation index for active branched-chains is proposed, and the distribution law of the coupling strength in a certain trajectory and workspace is studied. The results show that the inertia coupling strength indices between active branched-chains vary with the manipulator position and are symmetrically distributed in the workspace. This paper provides a theoretical basis for the joint controller design and structural parameter optimization of the polishing robot.

Growth of nickel single crystals with a diameter of 8 in. using the Czochralski method

We grew large single crystals of metal nickel with a maximum diameter of 8 in. using the Czochralski (CZ) method. Characteristics of the metal material, namely, the seed elongation and intense cooling radiation at high temperatures during crystal growth, are the main challenges when growing ingots with large diameters. These problems were resolved by optimizing the parameters related to crystal growth, such as reduction of crucible and ingot rotation speed, and adjustment of shoulder formation angle of ingot shape. The produced ingots were confirmed to be single crystals by the Laue back-reflection method. Wafers were cut from single crystal ingots using a multi-wire saw with diamond abrasive grains. A smooth, mirror-like surface was obtained on the wafers by using an ordinary mechanical polishing method. The full width at half maximum values of the X-ray rocking curve of the metal nickel crystal surface significantly depends on the surface treatment method. It was found that ordinary mechanical mirror polishing introduces strain on the surface and non-uniformity of the crystal orientation.

Milling force model for asymmetric end-mills during high-feed milling on AISI-P20

ABSTRACT Manufacturing molds for plastic parts injection are a particular machining domain, where challenging materials, like AISI P20 steel, are forced to satisfy the highest surface quality requirements. Before mirror polishing, milling operation is a common and challenging task due to drilling and milling with the same tool. Thus, special cutting tools, like asymmetric indexable type, are often used. This tool presents two geometrically equal positive inserts – one placed horizontally and the other vertically – for the flexible machining of holes, cavities, floors, and walls. Rough-medium milling operations lead to a complicated relationship between cutting conditions and geometrical tool parameters, making it challenging to balance the tool life of both inserts. The novelty of this work is to propose a model for cutting force prediction with an asymmetric tool to explain the separated behavior of both inserts and determine a better compromise between cutting conditions and tool life. The experimental tests were done for model validation and then wear cutting tests for testing improved cutting conditions. The results predicted by the model proved that by changing the depth of cut from 0.3 mm to 0.8 mm, the wear in both inserts was more balanced, increasing chip volume up to 1.7 times.

Research on the optical grinding and polishing technology of spherical mirror based on alloy steel materials

In Vietnam, the technology of fabricating spherical surfaces of glass lenses by the loose abrasive grinding method has been researched and widely applied. However, this technology does not really match the needs of grinding and polishing optically the sphere on the basis of alloy steel. This paper introduces some initial results in researching the technology of optical mirror polishing of alloy steel materials. The issues studied include the selection of processing methods and equipment, design and manufacture of auxiliary tools and machining tools, testing and setting up machining processes, and the methodology for characterisation product quality. A spherical mirror of 50 mm in diameter, 70 mm in spherical radius, based on alloy steel material has been optically polished. Test results show that the sample meets the requirements for optical products (N=1; ΔN=1, surface roughness Rz=0.05 μm).

Determination of Defect Concentrations in ²⁸Si Crystals Using EPR for the Realization of the Kilogram

To realize the kilogram using the X-ray crystal density method, <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">28</sup> Si crystals grown by the floating zone method were employed. Samples cut from two <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">28</sup> Si crystals, the AVO28 crystal (Si28-10Pr11 crystal) and the Si28-23Pr11 crystal, were analyzed by means of an electron paramagnetic resonance (EPR) spectroscopy. The samples were prepared by mirror polishing and subsequent etching using tetramethylammonium hydroxide (TMAH) solution. TMAH etching eliminates signals from the mechanically damaged surface layers of amorphous silicon and allows for the observation of small signals from vacancy defects in bulk crystals. In the study, the signal level of the vacancy defects was below the detection limit of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1 \times 10^{12}$ </tex-math></inline-formula> cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-3}$ </tex-math></inline-formula> , and the amount of vacancy correction required to realize the kilogram was estimated to be 0.00(23) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{g}$ </tex-math></inline-formula> for both <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">28</sup> Si crystals. Therefore, it was concluded that the 39(21) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{g}$ </tex-math></inline-formula> inconsistency between the kilogram realizations achieved using the two <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">28</sup> Si crystals reported thus far cannot be explained by the existence of vacancy defects that are EPR active in the dark or under illumination.

Enhancement of hardness of low alloy steel after low temperature plasma nitriding

The present work is focused on the plasma assisted nitriding of martensitic stainless steel at low temperature. Sample coupons of dimensions 8 × 8 × 6 mm3 were cut from the hardened and tempered steel sheet. Following grinding and mirror polishing samples were placed inside the chamber. At a low temperature of 460 °C (±10) nitriding was performed in the plasma generated by nitrogen and hydrogen gas mixture, Nitrided samples were then subjected to hardness measurements. The structural characterization was followed by X-ray diffraction (XRD) studies for the phase analysis. It was shown that even at a low temperature the surface modifies to high hardness for the improved tribological properties.

Galvanic Corrosion Behavior of Al Alloy A6061 / High-Tensile Strength Steel Couples Jointed By Friction Stir Lap Welding in an NaCl Solution

Recently, improvements in fuel efficiency of transportation systems have been called for, as part of measures to reduce carbon dioxide emissions. Reducing the body weight is quite effective in improving fuel efficiency. Therefore, part of heavier materials like steel is replaced by lighter materials such as aluminum alloys, carbon fiber reinforced plastics, and so on. However, when dissimilar materials are jointed, appropriate jointing methods are needed in terms of assembly, bonding performance, and costs. Friction stir welding (FSW) has attracted much attention as a promising jointing method in various engineering applications. FSW is a solid-state joining technique that has shown significant advantages over conventional fusion welding in terms of higher strength and quality of the joint produced. For this reason, FSW has attracted considerable attention for industrial applications, and further development of the technology is expected. However, during bonding of metallic materials by FSW, microstructure changes are produced that can affect their corrosion degradation. In this study, galvanic corrosion behavior of couples of A6061 and high-strength steel (SPCC) jointed by FSW in aqueous NaCl solutions is investigated.Friction stir lap welding was performed on A6061 and SPCC plate materials, and the corrosion behavior of the cross section was investigated by microstructure observation, hardness test, immersion test, and electrochemical measurement. The microstructure observation was performed using an optical microscope and a scanning electron microscope. On the A6061 side, after mirror polishing, further polishing was performed using a cross section polisher to observe grain boundaries and inclusions. Hardness testing was done to examine the change in hardness on A6061 with a micro Vickers hardness meter. The immersion test was conducted in an aqueous NaCl solution. In addition, micro-electrochemical polarization tests were performed on A6061 to investigate pitting potentials of each microstructure of A6061.It was found from the results of the surface observation that grain size and precipitate distributions were varied depending on the distance from the jointed part on A6061. The microstructures on A6061 after FSW were classified into 4 main regions: nugget zone (NZ), heat affected zone (HAZ), thermo-mechanically affected zone (TMAZ), and base metal (BM). It was found from the results of the hardness tests that BM has the highest hardness and that TMAZ, HAZ and NZ were softened. In the immersion tests, localized corrosion was observed mainly on BM region of A6061 at early stage of the galvanic corrosion. Micro-electrochemical polarization tests for A6061 revealed that pitting potential (E p) of NZ region was higher than BM. This suggests that pitting corrosion is less likely to occur on the regions of NZ and TMAZ rather than BM due to the change in the microstructure of A6061 caused by FSW. Acknowledgments This paper is based on results obtained from a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

Equivalent thin-plate method for stressed mirror polishing of an off-axis aspheric silicon carbide lightweight mirror.

No physical model of stressed mirror polishing, based on the small deflection and deformation of elastic thin plates, has been applied in processing lightweight mirrors. We propose an equivalent thin-plate method for the stressed loading of lightweight mirrors for the first time. Stressed loading and polishing of an aspheric lightweight mirror are simulated using the small-deflection deformation theory of an elastic thin plate. We simulate off-axis aspheric silicon carbide (SiC) lightweight mirrors with three different structures, determining the corresponding equivalent thickness plate in a lightweight structure with a nearly uniform surface density distribution and isotropic bending properties. We then establish a residual removal model of a stressed polishing surface, design the stressed loading equipment, and propose an iterative method for stressed polishing of an off-axis aspheric SiC lightweight mirror. The results demonstrate that it is feasible to choose a lightweight structure that performs full-aperture stressed polishing on off-axis aspheric lightweight mirrors consisting of SiC or other materials.

Dendrite-free Al recycling via electrodeposition using ionic liquid electrolytes: The effects of deposition temperature and cathode surface roughness

In this paper, the electrodeposition of Al from aluminum scrap alloys (A2020) on copper cathode substrates with varied surface roughness under different deposition temperatures was studied using low-temperature AlCl3-1-butyl-3-methyl-imidazolium chloride (BMIC) ionic liquid electrolytes. The bulk electrodeposition of Al was carried out under a voltage of 1.5 V at a stirring rate of 120 rpm using a fixed ionic liquid electrolyte concentration (molar ratio AlCl3: BMIC = 2:1). The effects of deposition temperature (range from 80 °C to 140 °C) and surface roughness of Cu cathode substrates (polished by 320, 600, 800, 1200 grits SiC sandpapers and mirror polishing process) on the morphology of deposited Al, current density, current efficiency and energy consumption, were investigated. The Al deposits were characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), profilometer, and electrochemical measurements for current density, current efficiency, and energy consumption. It is demonstrated that the deposition temperature and surface roughness of Cu electrodes play a critical role in the nucleation and growth of Al deposits. Higher deposition temperature promotes the diffusion and/or migration of Al2Cl7− ions and then enhances the current density and efficiency during the electrodeposition of Al. Smoother surface of Cu electrodes is preferred for the formation of dendrite-free Al deposits. Typically, on the mirror polished Cu electrode, no Al dendrite structure was observed, and only plate-like Al deposits were formed at the deposition temperature of 100 °C. Pure metallic Al was successfully deposited on Cu electrodes in AlCl3+BMIC ionic liquid electrolytes for all experiments with a current efficiency range from 72% to 99% and energy consumption of 4.6–6.3 kW h/kg Al.

Comprehensive study of the rapid stressed mirror polishing method for off-axis aspheric SiC thin-plate mirrors.

In this study, the stressed mirror polishing technique is used to perform off-axis aspheric silicon carbide (SiC) mirror full-aperture polishing for the first time. Mechanical and optical parameter analysis methods have been proposed. A medium-diameter off-axis aspheric SiC thin-plate mirror is used as a scaling model for an optical system mirror. A full diameter polishing simulation was completed, and a conceptual design for stress loading equipment is presented. An initial aspheric surface method for stressed mirror polishing of an off-axis aspheric SiC thin-plate mirror, providing a reference for rapid stress mirror polishing of SiC mirrors, is also proposed.

Off-axis parabolas super polished under stress: the case of the Roman Space Telescope coronagraphic instrument mirrors.

Direct imaging of exoplanets requires high contrast imaging techniques that demand tight tolerances on the optical surface error. The Nancy Grace Roman Space Telescope (RST) (previously named WFIRST) aims to perform direct imaging of SuperEarth-like exoplanets through its active coronographic instrument (CGI). Eight off-axis parabola (OAP) mirrors are utilised within the CGI to create a compact instrument and to ensure access to the pupil and focal planes. The surface form error and surface roughness of these relay optics directly impact the quality of the dark hole, and therfore the observable location for exoplanets. A new fabrication process for OAP manufacture via stressed mirror polishing (SMP) is presented in this paper. First, the design of the mirror substrate is investigated to create an innovative thickness distribution capable of producing the OAP geometry with a simple warping harness composed by two micrometer screws. Second, the novel design is implemented on a 60 mm diameter OAP prototype in Zerodur; a description of the fabrication process chain and the characterisation of the optical surface over all spatial frequencies are presented. Results from this first prototype demonstrated that the surface form error deviates from < 1 nm root means square (RMS) from the simulations and with a surface roughness of 2.1 Å Ra.

Direct non-destructive total reflection X-ray fluorescence elemental determinations in zirconium alloy samples.

The development of a direct non-destructive synchrotron-radiation-based total reflection X-ray fluorescence (TXRF) analytical methodology for elemental determinations in zirconium alloy samples is reported for the first time. Discs, of diameter 30 mm and about 1.6 mm thickness, of the zirconium alloys Zr-2.5%Nb and Zircalloy-4 were cut from plates of these alloys and mirror polished. These specimens were presented for TXRF measurements directly after polishing and cleaning. The TXRF measurements were made at the XRF beamline at Elettra synchrotron light source, Trieste, Italy, at two different excitation energies, 1.9 keV and 14 keV, for the determinations of low- and high-Z elements, respectively. The developed analytical methodology involves two complementary quantification schemes, i.e. using either the fundamental parameter method or relative sensitivity based method, allowing quantification of fifteen minor and trace elements with respect to Zr with very good precision and accuracy. In order to countercheck the TXRF analytical results, some samples were analyzed using the DC arc carrier distillation atomic emission spectrometry technique also, which shows an excellent agreement with the results of the TXRF-based methodology developed in this work. The present work resulted in a non-destructive TXRF elemental characterization methodology of metal and alloy samples avoiding the cumbersome dissolution and matrix separation which arenormally required in other techniques and traditional methods of TXRF determination. In addition, the production of analytical waste could also be avoided to a large extent. Although the work was carried out for specific applications in the nuclear industry, it is equally suitable for other such samples in different industrial applications.