Surface Engineering to Add a Surface Layer or Coating

Author(s):  
T. Dyl

Purpose: The aim of the study was description to the influence of technological parameters of burnishing process on the degree of relative strain hardening and surface roughness reduction ratio. Design/methodology/approach: Burnishing process carried out for stainless steels X2CrNiMo17-12-2. After the experimental research, it was determined that there was an increase in hardness and a decrease in roughness. The hardness was measured with the use of Vickers hardness tester. Observation of the microstructure of stainless steel samples was carried out using scanning electron microscopy and optical microscopy. The parameters of surface roughness measurements were performed to the principles contained in ISO standards. Findings: In the production and regeneration of metal products used in machine elements is important to technological quality surface layer. In surface engineering one of the ecological and economic treatments used for endurance and technological properties is burnishing. This is a surface forming a local plastic deformation based on the overall impression given by smooth and hard tool. Practical implications: The burnishing due the technological and economic aspect in the production and regeneration of machine parts in exchange for the abrasive processing can be used. In production engineering or technology of repair cylindrical outer surfaces (e.g. plugs propulsion shaft centrifugal pumps seawater) are finishing. You can therefore propose burnishing in exchange for abrasive machining. Originality/value: Important question to determine in the article of the research was to received appropriate technological quality. After the tests, it was found that the technological parameters are influenced by the hardness and the roughness of the outer cylindrical surfaces and the material ratio curve a convex shaped, which, taking into account the load capacity of the surface will be directly affected by its resistance to wear and corrosion of the surface layer.


2015 ◽  
Vol 237 ◽  
pp. 27-33 ◽  
Author(s):  
Joanna Kacprzyńska-Gołacka ◽  
Jerzy Smolik ◽  
Adam Mazurkiewicz ◽  
Jan Bujak ◽  
Halina Garbacz ◽  
...  

One of the most effective ways of shaping the operating parameters of functional elements is to modify the properties of a surface layer using modern technologies of surface engineering. The prospective directions in the development of surface engineering solutions are nanomultilayer coatings that enable effective shaping of surface layer properties. A very important factor in designing properties of PVD coatings, apart from their chemical composition, is their microstructure.The paper presents the influence of the microstructure of the nanomultilayer AlN-CrN-TiN coating on their tribological properties at elevated temperatures. The research methods were concentrated on the analysis of mechanical properties, microstructure, and tribological properties at increased temperatures. The studies on mechanical properties included tests on hardness using the nanoindentation method and tests on adhesion using the scratchtest method. The analysis of microstructure was performed using scanning microscopy. The tribological properties at high temperature were examined using the ball-on-disc method. The authors indicate that the AlN-CrN-TiN layers are characterised by excellent mechanical properties and tribological resistance. In this paper, the authors confirm that the microstructure of a nanomultilayer coating is important in shaping the mechanical and tribological properties of a PVD coating.


2015 ◽  
Vol 60 (3) ◽  
pp. 2161-2172 ◽  
Author(s):  
A. Mazurkiewicz ◽  
J. Smolik

AbstractThe dynamics of the development of modern technology depends, to a great extent, on the possibilities of producing the innovative materials with high functionality parameters, which could be used in modern, highly advanced technological processes. Surface engineering plays a very important role in this area. This is mainly due to the fact that, for many structural materials, the possibilities of classical formation of their properties (e.g., by heat treatment or the selection of the microstructure, chemical and phase composition) have been practically used up. The material and technological achievements in the surface engineering area allow the modification of the properties of the surface layer of tool and machine components. As a result, they may be better suited to work in increasingly difficult and more demanding conditions. The hybrid technologies, combining several different methods of surface treatment in one complex technological process, are the most advanced solutions compared to already known surface engineering methods. In the article, the authors present the possibilities of shaping the functional properties of the surface layer. The authors describe problems associated with the development of the hybrid technology and provide the examples of physical modelling, design, technological development, and the practical application of a hybrid technology. In this work, the authors also identify the areas whose development is needed for more effective transfer of surface engineering innovations to business applications.


Author(s):  
D. N. Braski ◽  
P. D. Goodell ◽  
J. V. Cathcart ◽  
R. H. Kane

It has been known for some time that the addition of small oxide particles to an 80 Ni—20 Cr alloy not only increases its elevated-temperature strength, but also markedly improves its resistance to oxidation. The mechanism by which the oxide dispersoid enhances the oxidation resistance is being studied collaboratively by ORNL and INCO Alloy Products Company.Initial experiments were performed using INCONEL alloy MA754, which is nominally: 78 Ni, 20 Cr, 0.05 C, 0.3 Al, 0.5 Ti, 1.0 Fe, and 0.6 Y2O3 (wt %).Small disks (3 mm diam × 0.38 mm thick) were cut from MA754 plate stock and prepared with two different surface conditions. The first was prepared by mechanically polishing one side of a disk through 0.5 μm diamond on a syntron polisher while the second used an additional sulfuric acid-methanol electropolishing treatment to remove the cold-worked surface layer. Disks having both surface treatments were oxidized in a radiantly heated furnace for 30 s at 1000°C. Three different environments were investigated: hydrogen with nominal dew points of 0°C, —25°C, and —55°C. The oxide particles and films were examined in TEM by using extraction replicas (carbon) and by backpolishing to the oxide/metal interface. The particles were analyzed by EDS and SAD.


Author(s):  
W. H. Wu ◽  
R. M. Glaeser

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.


Author(s):  
Teruo Someya ◽  
Jinzo Kobayashi

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).


Author(s):  
V. N. Filimonenko ◽  
M. H. Richman ◽  
J. Gurland

The high temperatures and pressures that are found in a spark gap during electrical discharging lead to a sharp phase transition and structural transformation in the surface layer of cemented carbides containing WC and cobalt. By means of X-ray diffraction both W2C and a high-temperature monocarbide of tungsten (face-centered cubic) were detected after electro-erosion. The W2C forms as a result of the peritectic reaction, WC → W2C+C. The existence and amount of the phases depend on both the energy of the electro-spark discharge and the cobalt content. In the case of a low-energy discharge (i.e. C=0.01μF, V = 300v), WC(f.c.c.) is generally formed in the surface layer. However, at high energies, (e.g. C=30μF, V = 300v), W2C is formed at the surface in preference to the monocarbide. The phase transformations in the surface layer are retarded by the presence of larger percentages of cobalt.Metallographic examination of the electro-eroded surfaces of cemented carbides was carried out on samples with 5-30% cobalt content. The specimens were first metallographically polished using diamond paste and standard procedures and then subjected to various electrical discharges on a Servomet spark machining device. The samples were then repolished and etched in a 3% NH4OH electrolyte at -0.5 amp/cm2. Two stage plastic-carbon replicas were then made and shadowed with chromium at 27°.


Author(s):  
B. Van Meerbeek ◽  
L. J. Conn ◽  
E. S. Duke

Restoration of decayed teeth with tooth-colored materials that can be bonded to tooth tissue has been a highly desirable property in restorative dentistry for many years. Advantages of such an adhesive restorative technique over conventional techniques using non-adhesive metal-based restoratives include improved restoration retention with minimal sacrifice of sound tooth tissue for retention purposes, superior adaptation and sealing of the restoration margins in prevention of caries recurrence, improved stress distribution across the tooth-restoration interface throughout the whole tooth, and even reinforcement of weakened tooth structures. The dental adhesive technology is rapidly changing. An efficient resin bond to enamel has already long been achieved. Its bonding mechanism has been fully elucidated and has proven to be a durable and reliable clinical treatment. However, bonding to dentin represents a greater challenge. After the failures of a dentin acid-etch technique in imitation of the enamel phosphoric-acid-etch technique and a bonding procedure based on chemical adhesion, modern dentin adhesives are currently believed to bond to dentin by a micromechanical hybridization process. This process is developed by an initial demineralization of the dentin surface layer with acid etchants exposing a collagen fibril arrangement with interfibrillar microporosities that subsequently become impregnated by low-viscosity monomers. Although the development of such a hybridization process has well been documented in the literature, questions remain with respect to parameters of-primary importance to adhesive efficacy.


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