Advancement in Ferrite-Based Alloy Coatings by Laser Cladding

2013 ◽  
Vol 591 ◽  
pp. 253-257 ◽  
Author(s):  
Hui Jun Yu ◽  
Ting He ◽  
Chuan Zhong Chen
Keyword(s):  
Wear Resistance ◽  
Surface Modification ◽  
Laser Cladding ◽  
High Performance ◽  
Surface Region ◽  
Price Ratio ◽  
Alloy Component ◽  
Near Surface ◽  
Development Tendency ◽  
Corrosion And Oxidation

Fe-based alloy is widely used for its good wear resistance and high performance-to-price ratio compared with other alloys. Laser cladding is a kind of valid method of metal surface modification, which has been successfully employed to modify the microstructure and/or composition of the near surface region to improve the wear, corrosion and oxidation resistance of a ferrite-based alloy component. In this paper, the recent research status in laser clad ferrite-based alloys is reviewed. The rules of designing laser cladding materials are introduced. The main problems and the solutions of the laser cladding materials application are analysized. The development tendency of laser cladding is forecast.

THE EFFECT OF RARE EARTH ON THE STRUCTURE AND PERFORMANCE OF LASER CLAD COATINGS

2006 ◽  
Vol 13 (04) ◽  
pp. 509-517 ◽  
Author(s):  
RUILIANG BAO ◽  
HUIJUN YU ◽  
CHUANZHONG CHEN ◽  
QING DONG
Keyword(s):  
Wear Resistance ◽  
Surface Modification ◽  
Rare Earth ◽  
Laser Cladding ◽  
Phase Structure ◽  
Wear Resistant Coating ◽  
Preliminary Discussion ◽  
Effect Mechanism ◽  
And Performance ◽  
Development Tendency

Laser cladding is one kind of advanced surface modification technology and has the abroad prospect in making the wear-resistant coating on metal substrates. However, the application of laser cladding technology does not achieve the people's expectation in the practical production because of many defects such as cracks, pores and so on. The addiction of rare earth can effectively reduce the number of cracks in the clad coating and enhance the coating wear-resistance. In the paper, the effects of rare earth on metallurgical quality, microstructure, phase structure and wear-resistance are analyzed in turns. The preliminary discussion is also carried out on the effect mechanism of rare earth. At last, the development tendency of rare earth in the laser cladding has been briefly elaborated.

Reduction in Wear Rate of α-Alumina and Silicon Nitride by Diffusional Surface Modification

1988 ◽  
Vol 140 ◽  
Author(s):  
A.K. Gangopadhyay ◽  
M.E. Fine ◽  
H.S. Cheng
Keyword(s):  
Wear Resistance ◽  
Thermal Expansion ◽  
Surface Modification ◽  
Silicon Nitride ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Surface Region ◽  
Lattice Parameter ◽  
Lower Thermal Expansion ◽  
Wear Modes

AbstractThe surface regions of α-alumina and hot pressed silicon nitride were modified by suitable alloying in order to improve their wear resistance. The surface modification in polycrystalline α-alumina was done by diffusing chromia into the surface region which resulted in the formation of a thin layer of A12O3 - Cr9O3 solid solution which has a lower thermal expansion coefficient than pure α-alumina. Also Cr2O3 has a larger lattice parameter than α-alumina thus during cooling the surface was put into compression. The surface region of hot pressed silicon nitride was modified by diffusing α-alumina into the surface which resulted in the formation of a thin sialon layer. A surface compressive stress was again introduced due to the lower thermal expansion coefficient and larger latticeparameter of sialon compared to silicon nitride.Wear tests were conducted against 52100 steel under both lubricated and unlubricated sliding contact using a block on ring apparatus. The wear resistance of chromia surface alloyed α-alumina was improved considerably over unalloyed α-alumina under both lubricated and unlubricated conditions. The wear resistance of alumina surface alloyed silicon nitride was also improved over unalloyed silicon nitride under both lubricated and unlubricated conditions.Different wear modes were identified by examining the worn surfaces under the scanning electron microscope.

Surface Modification of Tungsten Oxide-Based Photoanodes for Solar-Powered Hydrogen Production

2009 ◽  
Vol 1171 ◽  
Author(s):  
Nicolas Gaillard ◽  
Jess Kaneshiro ◽  
Eric L. Miller ◽  
Lothar Weinhardt ◽  
Marcus Bär ◽  
...  
Keyword(s):  
Surface Modification ◽  
Tungsten Oxide ◽  
Surface Region ◽  
Bottom Layer ◽  
Photocurrent Density ◽  
Charge Carriers ◽  
Near Surface ◽  
Solar Powered ◽  
Surface Modification Techniques ◽  
Pec Water Splitting

AbstractWe report on the development of tungsten-oxide-based photoelectrochemical (PEC) water-splitting electrodes using surface modification techniques. The effect of molybdenum incorporation into the WO3 bulk or the surface region of the film is discussed. Our data indicate that Mo incorporation in the entire film (WO3:Mo) results in poor PEC performances, most likely due to defects that trap photo-generated charge carriers. However, compared to a pure WO3 (WO3:Mo)-based PEC electrode, a 20% (100%) increase of the photocurrent density at 1.6 V vs. SCE is observed if the Mo incorporation is limited to the near-surface region of the WO3 film. The resulting WO3:Mo/WO3 bilayer structure is formed by epitaxial growth of the WO3:Mo top layer on the WO3 bottom layer, which allows an optimization of the electronic structure induced by Mo incorporation while maintaining good crystallographic properties.

Interface study of a high-performance W/B4C X-ray mirror

2010 ◽  
Vol 43 (6) ◽  
pp. 1431-1439 ◽  
Author(s):  
Peter Siffalovic ◽  
Matej Jergel ◽  
Livia Chitu ◽  
Eva Majkova ◽  
Igor Matko ◽  
...  
Keyword(s):  
High Performance ◽  
Hexagonal Phase ◽  
Surface Region ◽  
Grazing Incidence ◽  
Interface Roughness ◽  
Growth Exponent ◽  
Ozone Treatment ◽  
Excellent Thermal Stability ◽  
Near Surface ◽  
X Ray

A high-performance W/B4C multilayer mirror with 80 periods of nominally 1.37 nm was measured by grazing-incidence small-angle X ray scattering (GISAXS) in order to analyse the lateral and vertical correlations of the interface roughness within the framework of a scaling concept of multilayer growth. A dynamic growth exponentz= 2.19 (7) was derived, which is close to the value predicted by the Edwards–Wilkinson growth model. The effective number of correlated periods indicates a partial replication of the low interface roughness frequencies. A simulation of the GISAXS pattern based on the Born approximation suggests a zero Hurst fractal parameterHand a logarithmic type of autocorrelation function. The as-deposited mirror layers are amorphous and exhibit excellent thermal stability up to 1248 K in a 120 s rapid thermal vacuum annealing process. At higher temperatures, the B4C layers decompose and poorly developed crystallites of a boron-rich W–B hexagonal phase are formed, and yet multilayer collapse is not complete even at 1273 K. Ozone treatment for 3000 s in a reactor with an ozone concentration of 150 mg m−3results in the formation of an oxidized near-surface region of a thickness approaching ∼10% of the total multilayer thickness, with a tendency to saturation.

Effects of sequential He+ and Ar+ implantation on surface properties of polymers

1996 ◽  
Vol 11 (10) ◽  
pp. 2661-2667 ◽  
Author(s):  
Gopal R. Rao ◽  
Eal H. Lee
Keyword(s):  
Wear Resistance ◽  
Surface Properties ◽  
Ion Irradiation ◽  
Surface Hardness ◽  
Wear Test ◽  
Surface Region ◽  
Near Surface ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Hardness Increase

Three important polymers: polystyrene (PS), poly ether ether ketone (PEEK), and polyimide Kapton, were irradiated separately with 1 MeV He+, 1 MeV Ar+, and 1 MeV He+ followed by 1 MeV Ar+ sequentially, to a fluence of 3 × 1019 ions/m2 for each ion. The specimens were characterized for changes in surface hardness using a nanoindentation technique, and wear resistance using a reciprocating sliding wear apparatus with a steel ball counterface. Results indicated that while all polymers showed higher hardness values after ion irradiation, the dual irradiation resulted in the largest hardness increase, greater than for the single ion-irradiated specimens. Wear test results also indicated that the dual He+ + Ar+ irradiation resulted in the best improvement in wear resistance of the polymers. These improvements in properties are a consequence of cross-linking of the polymer material caused by the ion irradiation. Linear energy transfer considerations showed that the dual He+ + Ar+ implantation was better because it combined a deeper implant, in the form of He, along with Ar irradiation which resulted in a shallower but more highly cross-linked layer at the near surface. Thus a deeper and graded cross-linked surface region was formed. The study shows that there is greater flexibility for tailoring surface properties of polymers by using a judicious combination of ion species, ion energies, and fluences.

Research Progress in Laser Clad Nickel-Based Alloy Coatings

2013 ◽  
Vol 833 ◽  
pp. 252-256 ◽  
Author(s):  
Hui Jun Yu ◽  
Ting He ◽  
Chuan Zhong Chen
Keyword(s):  
Wear Resistance ◽  
Rapid Solidification ◽  
Laser Cladding ◽  
Research Progress ◽  
Rapid Solidification Technique ◽  
Clad Layer ◽  
Nickel Based Alloy ◽  
Metallurgical Bond ◽  
Development Tendency

Laser cladding, as a newly developed rapid solidification technique, is to cover a particular part of the substrate with another material that has superior properties, producing a metallurgical bond between the two materials with minimal dilution of the clad layer by the substrate. In this paper, the research progress in laser clad nickel based alloys is reviewed. The microstructures and wear resistance of the coatings are introduced, the main problems and some solutions of the laser cladding are analysized, and the development tendency and application prospect of laser cladding is also pointed out.

Preparation of cross-sectional samples for near-surface TEM studies

1987 ◽  
Vol 45 ◽  
pp. 380-381
Author(s):  
R.C. Dickenson ◽  
K.R. Lawless
Keyword(s):  
Standard Sample ◽  
Surface Region ◽  
Specimen Preparation ◽  
Thick Sheet ◽  
Drill Bit ◽  
Sample Holder ◽  
Metal Interface ◽  
Cross Sectional ◽  
Near Surface ◽  
Cold Worked

In thermal oxidation studies, the structure of the oxide-metal interface and the near-surface region is of great importance. A technique has been developed for constructing cross-sectional samples of oxidized aluminum alloys, which reveal these regions. The specimen preparation procedure is as follows: An ultra-sonic drill is used to cut a 3mm diameter disc from a 1.0mm thick sheet of the material. The disc is mounted on a brass block with low-melting wax, and a 1.0mm hole is drilled in the disc using a #60 drill bit. The drill is positioned so that the edge of the hole is tangent to the center of the disc (Fig. 1) . The disc is removed from the mount and cleaned with acetone to remove any traces of wax. To remove the cold-worked layer from the surface of the hole, the disc is placed in a standard sample holder for a Tenupol electropolisher so that the hole is in the center of the area to be polished.

The Effects of Ion Implantation on the Surface Features of Inconel 600

1985 ◽  
Vol 43 ◽  
pp. 288-289
Author(s):  
John D. Rubio
Keyword(s):  
Grain Boundary ◽  
Ion Implantation ◽  
Nuclear Power ◽  
Power Plants ◽  
Surface Region ◽  
Selective Dissolution ◽  
Boundary Region ◽  
Near Surface ◽  
Inconel 600 ◽  
Steam Generator Tubing

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.

Microstructural changes of Aluminum Nitride after laser irradiation and electroless copper deposition

1994 ◽  
Vol 52 ◽  
pp. 636-637
Author(s):  
S. Cao ◽  
A. J. Pedraza ◽  
L. F. Allard
Keyword(s):  
Aluminum Nitride ◽  
Laser Irradiation ◽  
Electroless Deposition ◽  
Thermal Evaporation ◽  
Surface Region ◽  
Near Surface ◽  
Laser Patterning ◽  
Electroless Copper ◽  
Excimer Laser Irradiation ◽  
Laser Effect

Excimer-laser irradiation strongly modifies the near-surface region of aluminum nitride (AIN) substrates. The surface acquires a distinctive metallic appearance and the electrical resistivity of the near-surface region drastically decreases after laser irradiation. These results indicate that Al forms at the surface as a result of the decomposition of the Al (which has been confirmed by XPS). A computer model that incorporates two opposing phenomena, decomposition of the AIN that leaves a metallic Al film on the surface, and thermal evaporation of the Al, demonstrated that saturation of film thickness and, hence, of electrical resistance is reached when the rate of Al evaporation equals the rate of AIN decomposition. In an electroless copper bath, Cu is only deposited in laser-irradiated areas. This laser effect has been designated laser activation for electroless deposition. Laser activation eliminates the need of seeding for nucleating the initial layer of electroless Cu. Thus, AIN metallization can be achieved by laser patterning followed by electroless deposition.

OLIN C197

Alloy Digest ◽  
1999 ◽  
Vol 48 (1) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Wear Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Performance ◽  
Corrosion And Wear ◽  
Contact Forces ◽  
High Current ◽  
Lower Strength ◽  
Current Carrying Capability

Abstract Olin C197 is a second-generation high performance alloy developed by Olin Brass. It has a strength and bend formability similar to C194 (see Alloy Digest Cu-360, September 1978), but with 25% higher electrical and thermal conductivity. High conductivity allows C197 to replace brasses and bronzes in applications where high current-carrying capability is required. Also, the strength of C197 provides higher contact forces when substituted for many lower strength coppers. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion and wear resistance as well as forming and joining. Filing Code: CU-627. Producer or source: Olin Brass.

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