Cu + TiB2 composite filler for brazing Al2O3 and Ti-6Al-4V alloy

Al₂O₃ and Ti-6Al-4V alloy were brazed using Cu + TiB₂ composite filler, which manufactured by mechanical milling of Cu and TiB₂ powders. Typical interface microstructure of joint was Al₂O₃/Ti₄(Cu,Al)₂O/Ti₂Cu + Ti₃Al + Ti₂(Cu,Al)/Ti₂(Cu,Al) + AlCu₂Ti/Ti₂Cu + AlCu₂Ti + Ti₃Al + Ti₂(Cu,Al) + TiB/Ti(s.s) + Ti₂Cu/Ti-6Al-4V alloy. Based on temperature- and time-dependent compositional change, the formation of intermetallics in joint was basically divided into four stages: formation of interfacial Ti₄(Cu,Al)₂O in Al₂O₃ side, formation of Ti₂Cu, Ti₃Al, TiB, Ti₂Cu, and AlCu₂Ti in layers II and IV, formation of Ti₂(Cu,Al) and AlCu₂Ti in layer III, formation of Ti + Ti₂Cu hypereutectoid organization adjacent to Ti-6Al-4V alloy. TiB in situ synthesized in joint not only acted as low thermal expansion coefficient reinforcement to improve the mechanical properties at room temperature, but also as skeleton ceramic of joint to increase high temperature mechanical properties of Al₂O₃/Ti-6Al-4V alloy joint increasing. When the joint containing 30 vol.% TiB brazed at 930 °C and 10 min of holding time, the maximum room temperature shear strength of joint was 96.76 MPa, and the high temperature shear strength of joint was 115.16 MPa at 800 °C.     

High-temperature corrosion of Ti and Ti-6Al-4V alloy

Pure titanium and Ti-6Al-4V were exposed at 750°C in an H₂/H₂O/H₂S P_{O 2}10^–18 Pa and P_{S 2}10^–1 Pa), H₂/H₂O (P_{O 2}10^–18 Pa) and air environments for up to 240 hr. The corrosion kinetics, obtained by the discontinuous gravimetric method, showed that the sulfidation/oxidation kinetics were linear for Ti and linear-parabolic for Ti-6Al-4V in the H₂/H₂O/H₂S environment. Both materials obeyed parabolic rate laws in the H₂/H₂O atmosphere after a transient period, and linear-parabolic rate laws in air. After exposure to the H₂/H₂O/H₂S atmosphere, the titanium specimen displayed a double scale of TiO₂ with an intervening TiS₂ film between the double-layered scale of TiO₂ and the substrate. Ti-6Al-4V also contained a double layer of TiO₂ together with a stratum consisting of Al₂S₃, TiS₂ and vanadium sulfide at the junction of the inner TiO₂ layer and substrate. Some Al₂O₃ precipitated in the external portion of the outer TiO₂ layer. Following oxidation in the low-P_{O 2} atmosphere a double-layered oxide of TiO₂ scale formed on both Ti and Ti-6Al-4V. The scale on Ti-6Al-4V also contained an -Al₂O₃ film situated between the outer and inner (TiO₂) layers. For both materials, multilayered-scale formation characterized air oxidation. In detail a multilayered oxide scale of TiO₂ formed on the air-oxidized Ti, while a multilayered oxide scale with alternating layers of Al₂O₃/TiO₂ developed on Ti-6Al-4V oxidized in air.     

Apatite formation on anodized Ti-6Al-4V alloy in simulated body fluid

Titania layers were successfully prepared on the surfaces of Ti-6Al-4V alloy via anodic oxidation in H₂SO₄ or Na₂SO₄ solutions at room temperature. The titania layers consisted of pure rutile or a mixture of anatase and rutile structures after the Ti-6Al-4V alloy had been anodized in 1.0 M H₂SO₄ solution at 150 V or 0.5M Na₂SO₄ solution at 100 or 130 V. Good apatite-forming ability was demonstrated in simulated body fluid. However, surface layers with mainly titanium metallic phase or a pure anatase structure did not possess the ability to induce apatite formation. Anodic oxidation is an effective method to prepare bioactive Ti-6Al-4V alloy that can be used as an artificial bone substitute under load-bearing applications.     

Brazing of 6061 aluminum alloy/Ti-6Al-4V using Al-Si-Cu-Ge filler metals

Al-8.4Si-20Cu-10Ge and mixed rare-earth elements (Re) containing Al-8.4Si-20Cu-10Ge-0.1Re filler metals were used for brazing of 6061 aluminum alloy/Ti-6Al-4V. The addition of 20 wt.% copper and 10 wt.% germanium into the Al-12Si filler metal lowered the solidus temperature from 586 °C to 489 °C and the liquidus temperature from 592 °C to 513 °C. The addition of 0.1 wt.% rare-earth elements into Al-8.4Si-20Cu-10Ge alloy caused remarkable Al-rich phase refinement and transformed the needle-like Al₂Cu intermetallic compounds into block-like shapes. Shear strengths of the 6061 aluminum alloy/Ti-6Al-4V joints with the two brazing filler metals, Al-8.4Si-20Cu-10Ge and Al-8.4Si-20Cu-10Ge-0.1Re, varied insignificantly with brazing periods of 10-60 min. The average shear strength of the 6061 aluminum alloy/Ti-6Al-4V joints brazed with Al-8.4Si-20Cu-10Ge at 530 °C was about 20 MPa. Rare-earth elements appeared to improve the reaction of the Al-8.4Si-20Cu-10Ge filler metal with Ti-6Al-4V. The joint shear strength of the 6061 aluminum alloy/Ti-6Al-4V with Al-8.4Si-20Cu-10Ge-0.1Re reached about 51 MPa.     

Evaluation of hydrogen absorption behaviour during acid etching for surface modification of commercial pure Ti, Ti-6Al-4V and Ni-Ti superelastic alloys

The hydrogen absorption behaviour during acid etching for the surface modification of commercial pure Ti, Ti-6Al-4V and Ni-Ti superelastic alloys has been investigated on the basis of the surface morphology, electrochemical behaviour and hydrogen thermal desorption analysis. To simulate the conventional acid etching for the improvement of the biocompatibility of Ti alloys, the specimens are immersed in 1 M HCl, 1 M H₂SO₄ or 0.5 M HCl + 0.5 M H₂SO₄ aqueous solution at 60 °C. Upon immersion, commercial pure Ti absorbs substantial amounts of hydrogen irrespective of the type of solution. In H₂SO₄ or HCl + H₂SO₄ solutions, the hydrogen absorption occurs for a short time (10 min). For Ti-6Al-4V alloy, no hydrogen absorption is observed in HCl solution, whereas hydrogen absorption occurs in other solutions. For Ni-Ti superelastic alloy, the amount of absorbed hydrogen is large, resulting in the pronounced degradation of the mechanical properties of the alloy even for an immersion time of 10 min, irrespective of the type of solution. The hydrogen absorption behaviour is not necessarily consistent with the morphologies of the surface subjected to corrosion and the shift of the corrosion potential. The hydrogen thermal desorption behaviour of commercial pure Ti and Ni-Ti superelastic alloy are sensitively changed by acid etching conditions. The present results suggest that the evaluation of hydrogen absorption is needed for each condition of acid etching, and that the conventional acid etching often leads to hydrogen embrittlement.     

Thermal stability and oxidation resistance of laser clad TiVCrAlSi high entropy alloy coatings on Ti-6Al-4V alloy

TiVCrAlSi high entropy alloy coatings were deposited on Ti-6Al-4V alloy by laser cladding. SEM, XRD and EDS analyses show that, the as-clad coating is composed of (Ti,V)₅Si₃ and a BCC solid solution. After annealing at 800 °C for 24 h under vacuum, the coating is composed of (Ti,V)₅Si₃, Al₈(V,Cr)₅, and a BCC solid solution. The temperature-dependent phase equilibrium for the coating material calculated by using the CALPHAD method, indicates that above 880 °C the stable phases existing in the coating material are a BCC solid-solution and (Ti,V)₅Si₃. When the temperature is below 880 °C, the stable phases are (Ti,V)₅Si₃, Al₈(V,Cr)₅, and a BCC solid solution. In order to validate the calculation results, they were compared with TiVCrAlSi alloy samples prepared by arc melting, encapsulated in quartz tubes under vacuum, annealed at 400-1100 °C for 3 days and water-quenched. XRD analysis shows that the experimental phase composition agrees with the thermodynamic calculations. After vacuum annealing, there is a small increase of hardness for the laser clad TiVCrAlSi coating, which is due to the formation of Al₈(V,Cr)₅. The oxidation tests show that the TiVCrAlSi coating effectively improves the oxidation resistance of Ti-6Al-4V at 800 °C in air. The formation of a dense and adherent scale consisting of SiO₂, Cr₂O₃, TiO₂, Al₂O₃ and a small amount of V₂O₅ is supposed to be responsible for the observed improvement of the oxidation resistance.     

High temperature corrosion mechanisms of certain new TiAl-based intermetallic alloys in an aggressive H2/H2O/H2S environment at 850 °C

High temperature corrosion behaviour of three TiAl-based intermetallic alloys - Ti-44Al-8Nb-1B, Ti-46Al-8Nb-1B and Ti-48Al-2Nb-2Cr-1B (at.%) - was studied in an environment of H₂/H₂S/H₂O yielding p_S2 ∼ 6.8 × 10⁻¹ Pa and p_O2 ∼ 1.2 × 10⁻¹⁵ Pa potentials at 850 °C. The kinetic results obtained by a discontinuous gravimetric method indicate that increase in Al and Nb concentrations led to enhanced high temperature corrosion resistance, the corrosion resistance decreasing in the order: Ti-46Al-8Nb-1B > Ti-44Al-8Nb-1B > Ti-48Al-2Nb-2Cr-1B. The scale development studies using SEM, TEM, EDX, WDS and XRD confirmed the formation of a multilayered scale on all materials. An outer layer consisting of TiO₂ existed beneath which an Al₂O₃ layer was present. Then a layer of TiO₂ formed again, below which an Al-enriched NbAl₃ was observed. A TiS layer was found beneath the NbAl₃ layer. The formation of TiS led to the development of a NbAl₃ band between the multilayered scale and the substrate.     

Microstructure characteristics of Ti3Al/TiC ceramic layer deposited by laser cladding

Al + TiC laser cladding coatings were prepared on Ti-6Al-4V alloy by CO₂ laser cladding technique. The microstructure, micro-hardness and phase constitutes of the laser cladding layer were investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and microsclermeter. The results indicated that the laser cladding layer solidified into the fine microstructure rapidly, and TiC hard phase was dispersived in the cladding layer. When the mass percent of TiC was 40%, the micro-hardness (1100HV_0.2-1250HV_0.2) of Al + TiC cladding layer was 3 times more than that of the Ti-6Al-4V alloy substrate (350-370HV_0.2). The cladding layer mainly consisted of α-Ti (Al), β-Al (Ti), Ti₃Al, TiAl, Al₃Ti and TiC phase. There phases were beneficial to improve the hardness and wear resistance of the cladding layer.     

Surface characterization of passive film formed on nitrogen ion implanted Ti-6Al-4V and Ti-6Al-7Nb alloys using SIMS

The aim of this paper is to study the effect of N⁺ ion implantation on corrosion and phase formation on the implanted surfaces of Ti-6Al-4V and Ti-6Al-7Nb alloys. Nitrogen ion was implanted on Ti-6Al-4V and Ti-6Al-7Nb alloys at an energy of 70 and 100 keV, respectively using a 150 keV accelerator at different doses ranging from 5 × 10¹⁵ to 2.5 × 10¹⁷ ions/cm². Electrochemical studies have been carried out in Ringer’s solution in order to determine the optimum dose that can give good corrosion resistance in a simulated body fluid condition. The implanted surfaces of such modified doses were electrochemically passivated at 1.0 V for an hour. Secondary ion mass spectroscopy was used to study and characterize titanium oxide and titanium nitride layers produced on implanted surface and to correlate them with the corrosion resistance. The nature of the passive film of the implanted-passivated specimen was compared with the unimplanted-passivated as well as as-implanted specimens.     

Improving the strength of brazed joints with in situ synthesized TiB whiskers

TiB whiskers have been in situ synthesized as reinforcements in 73Cu-27Ti (wt.%) active brazing filler alloy used for the joining of Al₂O₃ and Ti-6Al-4V alloy. The results show that TiB whiskers served as an effective reinforcement phase aid to decrease the residual stress and increase the shear strength of joints. The shear strength of the joint, containing 30 vol.% TiB whiskers was about 239% higher than that of the joint brazed without TiB whiskers.     

Biomimetic deposition of apatite coatings on micro-arc oxidation treated biomedical NiTi alloy

The biomedical NiTi alloy was treated by micro-arc oxidation in an electrolytes containing sodium aluminate and sodium hypophosphite at 400 V constant voltages for 30 min. The MAO-treated NiTi has a porous microstructure on its surface and coatings consisting only of the γ-Al₂O₃ phase. The ceramic coating prepared by micro-arc oxidation is composed of Al, Ti, Ni, O, and P with the atomic concentration of 26.98%, 3.67%, 3.33%, 65.30% and 0.72%, respectively. The MAO-treated NiTi was soaked in a simulated body fluid (1.0SBF) to investigate the biomimetic deposition of apatite on the surface of Al₂O₃ coated NiTi alloy. It was found that Al₂O₃ coated NiTi alloy shows an excellent apatite-forming ability after soaking in a simulated body fluid (1.0SBF) for 14 days, while no apatite-forming ability was observed on bared NiTi alloy even though soaking time is up to 28 days.     

Fretting contact study of Ti-6Al-4 V/graphite couples in a dry shaft/bearing contact with thrust: Influence of plasma nitriding of the titanium alloy

Fretting wear or wear by small displacements is defined when two contacting surfaces (first-bodies) are subjected to small amplitude reciprocating motion of micron order. This phenomenon is observed in many mechanical assemblies and it can significantly reduce the contact mechanisms life.This paper reports on the influence of nitriding treatment of the titanium alloy on the fretting tribological behaviour of graphite/Ti-6Al-4 V couple in a dry shaft/bearing contact with thrust. Two contact geometries are investigated: cylinder-in-cylinder and flat/flat. These fretting contacts are subjected to low-amplitude oscillatory movements, with temperature reaching 270 °C.The nitriding treatment for the Ti-6Al-4 V was carried out with a gas mixture N₂/H₂ at moderate temperature (700 °C) for 12 h. In these conditions, the maximum surface hardness was improved by a factor three.In this study, the mechanism of transfer and wear of graphite against Ti-6Al-4 V nitrided or not, have been studied with a scanning electron microscope, an optical microscope and an interferential microscope.The morphological and profile analysis performed on rubbing surfaces showed various aspects of wear: prints, craters, transfer ... and allowed to explain the location, development and origin of the degradation.The friction couples have showed differences between the tests realised with the shafts with or without nitriding and especially at an elevated temperature.We discuss the experimental results and we suggest several possibilities in order to understand some specific tribological behaviour: impact of the third body, of the abrasion, etc.     

Mechanical and electrochemical characterization of Ti-12Mo-5Zr alloy for biomedical application

We have fabricated a new β metastable titanium alloy that comprised of non-toxic elements Mo and Zr. Ingot with composition of Ti-12Mo-5Zr is prepared by melting pure metals in a vacuum non-consumable arc melting furnace. The alloy is then homogenized and solution treated under different temperature. The alloy is characterized by optical microscopy, X-ray diffraction, tensile tests and found to have an acicular martensitic α″ + β structure and dominant β phase for the 1053 K and 1133 K solution treatment samples, respectively. The elastic modulus of the latter is about 64 GPa, which is much lower than those of pure Ti and Ti-6Al-4V alloy. In addition, it had moderate strength and much higher microhardness as compared with Ti-6Al-4V alloy. The results show better mechanical biocompatibility of this alloy, which will avoid stress shielding and thus prevent bone resorption in orthopedic implants applications. As long-term stability in biological environment is required, we have also evaluated the electrochemical behavior in a simulated body fluid (Hank's solution). Potentiodynamic polarization curves exhibits that the 1133 K solution treatment Ti-12Mo-5Zr sample has better corrosion properties than Ti-6Al-4V and is comparable to the pure titanium. The good corrosion resistance combined with better mechanical biocompatibility makes the Ti-12Mo-5Zr alloy suitable for use as orthopedic implants.     

Effect of surface treatment on electrochemical behavior of CP Ti, Ti-6Al-4V and Ti-13Nb-13Zr alloys in simulated human body fluid

The effect of an alkaline surface treatment on the electrochemical behavior of CP titanium, Ti-6Al-4V and Ti-13Nb-13Zr has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Experiments were performed in Hank’s solution as a function of immersion time. The electrochemical behavior of untreated alloys was also studied. Potentiodynamic polarization experiments conducted after 1 and 168 h of immersion in Hank’s solution indicated minimal change in passive current density for the untreated alloys. EIS data obtained after 1, 24, 72 and 168 h for untreated alloys also indicated minimal change in passive film resistance. In the case of surface-treated alloys, EIS revealed the formation of one additional layer on CP Ti and two additional layers on Ti-6Al-4V and Ti-13Nb-13Zr alloys after surface treatment and immersion in Hank’s solution. Some ideas about the nature of these layers have been obtained by fitting the EIS data to equivalent electrical circuit models. The surfaces of the treated Ti-alloys were also characterized using X-ray diffraction and scanning electron microscopy. The first additional layer has been identified as a sodium titanate hydrogel layer and the second layer, as an apatite layer. The apatite nucleation and growth on the surface occurred after immersion in Hank’s solution. Ti-6Al-4V and Ti-13Nb-13Zr alloys exhibited higher apatite film resistance compared to CP Ti.     

Corrosion Resistance and Color Properties of Anodized Ti-6Al-4V

In this research, color anodizing of Ti-6Al-4V alloy was performed in phosphoric acid solution of 0.4 M concentration and within 30 s in different voltages (10-120 V) of a DC power supply. The effect of anodizing voltages on the color and thickness of anodized layers on Ti-6Al-4V alloy surface was surveyed. Thickness and refractive index of layers were measured by spectrophotometery and reflectance curves. According to the results, thickness of layers increased with increasing anodizing voltage and was in the range of 38-167 nm. Also the refractive index of anodic film was approximately constant at about 2 and increased inconsiderably with increasing anodizing voltage. Corrosion resistance of the anodized samples in 20 and 50 V was surveyed in physiological solutions of Ringer’s solution, Artificial Saliva solution, and Ringer’s + 150 mM H₂O₂ solution at the temperature of 37 °C by potentiodynamic polarization method. The anodized sample in 50 V indicated lower corrosion rate than the non-anodized sample as well as the sample which was anodized in 20 V in all solutions. The non-anodized sample indicated the highest corrosion rate of about 0.25 μA cm⁻².     

Nickel titanium and nickel titanium hafnium shape memory alloy thin films

Shape memory alloy (SMA) coatings of NiTi and NiTiHf have been deposited onto Si substrates using pulse DC sputtering. Coatings of NiTi with compositions containing 45 to 65 at.% Ti have been fabricated by co-sputtering NiTi with Ti. NiTiHf coatings with Hf compositions ranging from 2 to 30 at.% Hf have been fabricated by co-sputtering NiTi with Hf. XRD results reveal the as-deposited coatings as amorphous. A high temperature, 1100 °C anneal followed by a low temperature, 550 °C anneal was employed to crystallise the coatings. The XRD then shows the coatings to be martensitic at room temperature.Two sets of samples were produced for characterisation; one set was used for indentation studies and the other set used to prepare freestanding films required for differential scanning calorimetry (DSC) studies.Using the DSC, a NiTi coating containing 52 at.% Ti shows an endothermic austenite peak phase transformation, (A_p) at around 105 °C and an exothermic peak martensite phase transformation, (M_p) at 65 °C, resulting in a hysteresis of 40 °C. For a NiTi coating containing 65 at.% Ti the hysteresis remained unchanged at 40 °C, but there was a decrease in the phase transformation enthalpies when compared with the coatings containing 52 at.% Ti. Calculated phase transformation enthalpies in the NiTi coatings ranged from 6 to 13 J/g for the austenite phase and − 8 to − 11 J/g for the martensite phase.The NiTiHf coating shows SMA behaviour for a film containing 30 at.% Hf. DSC reveals an ‘R’ phase transition in this film. It is understood that this phase is present in films that have high internal stresses and is understood to nucleate near Ti₃Ni₄ precipitates. Phase transformation temperatures occur at 98 °C and 149 °C during heating and occur at 99 °C during cooling. Phase transformation enthalpies range between 2 and 3 J/g for the austenite phase and − 7 J/g for the martensite phase.A scratch tester equipped with a 5 mm spherical tip has been utilised with loads ranging from 1 to 5 N to determine the recovery properties of the films. The results in this study conclude that NiTi films containing 65 at.% Ti deform 3 times more than films containing 52 at.% Ti. For NiTiHf thin films, increasing the Hf composition from 2 at.% to 30 at.%, doubled the deformation measured in the coatings.     

Influence of fluoride ion on the electrochemical behaviour of β-Ti alloy for dental implant application

The corrosion behaviour of Ti-15Mo alloy in 0.15 M NaCl containing 0.01, 0.03, 0.06 and 0.5 M NaF is evaluated and its protective ability is compared with that of CP-Ti and Ti-6Al-4V alloy, to ascertain their suitability for dental implant application. The steady state current density of CP-Ti and, Ti-15Mo and Ti-6Al-4V alloys in 0.15 M NaCl containing 0.03 M NaF at 200 mV vs. SCE is found to be 1, 2 and 6 μA/cm², respectively, which indicate that all of them could offer a better corrosion resistance in the potential range that could exists in the oral environment.     

Enthalpy of formation of selected mixed oxides in a CaO-SrO-Bi2O3-Nb2O5 system

The heats of drop-solution in 3Na₂O + 4MoO₃ melt at 973 K and 1073 K for calcium and strontium carbonates, Bi₂O₃, Nb₂O₅ and several stoichiometric mixed oxides in CaO-Nb₂O₅, SrO-Nb₂O₅ and Bi₂O₃-Nb₂O₅ systems were measured using a Setaram Multi HTC-96 calorimeter. The values of enthalpy of formation from constituent binary oxides at 298 K, Δ_oxH, were derived for the mixed oxides under investigation: Δ_oxH(CaNb₂O₆) = −132.0 ± 23.8 kJ mol⁻¹, Δ_oxH(Ca₂Nb₂O₇) = −208.0 ± 31.9 kJ mol⁻¹, Δ_oxH(SrNb₂O₆) = −167.9 ± 19.1 kJ mol⁻¹, Δ_oxH(Sr₂Nb₂O₇) = −289.2 ± 37.5 kJ mol⁻¹ and Δ_oxH(BiNbO₄) = −41.9 ± 11.1 kJ mol⁻¹. Additionally, the values Δ_oxH for other mixed oxides with different stoichiometries were estimated on the basis of these experimental results.     

Formation of nanoporous titania on bulk titanium by hybrid surface mechanical attrition treatment

Titanium has been used as an important implant material in humans, and it is important to investigate the interaction between titanium and H₂O₂ produced from the inflammatory response during the implantation procedure. However, the reports about the interaction between H₂O₂ and nanostructured or ultrafine-grained Ti are still very limited. In this work, the interaction between H₂O₂ and bulk Ti with a nanostructure surface was reported. At first, a commercial pure Ti plate underwent a surface mechanical attrition treatment (SMAT) in vacuum for 1 h to produce a nanocrystalline layer of Ti about 30 μm thick. Then the SMAT Ti was immersed into hydrogen peroxide solution for 24 h at 25 °C, and nanoporous titania was produced on the SMAT Ti surface. The nanoporous structure could be retained even after calcinations at 600 °C, while only intergranular corrosion appeared in coarse-grained Ti after the same chemical treatment.     

Microstructure and properties of TiB/Ti-6Al-4V coatings produced with laser treatments

TiB/Ti-6Al-4V metal-matrix composite (MMC) layers were produced on Ti-6Al-4V substrates by laser cladding. A TiB₂/Ti powder mixture was used as a precursor to obtain a dispersion of TiB needles in the Ti alloy matrix, with the aid of an exothermic reaction between TiB₂ and Ti. A eutectic microstructure was obtained that consisted of an extremely homogeneous dispersion of TiB eutectic needles in the Ti alloy matrix, having a volume fraction as high as 0.33. Also, an equilibrium-like microstructure was found, consisting of a dispersion of both primary and eutectic TiB needles inside the Ti alloy matrix. An analysis of the geometry of the layers was performed and proved successful in determining the percentage of B. Further, it correctly predicted the variation of atomic B content as a function of laser power. The relative wear resistance coefficient, defined as the wear coefficient of the uncoated matrix divided by that of coating, shows an improvement by a factor as high as 1500 for the eutectic microstructure. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appeared on pp. 411–18 of the Proceedings.