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1

Finishing intermetallic coatings in order to reduce the surface roughness

Dyl T. C.

Journal of KONES

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2013

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Vol. 20, No. 1

77--82

EN

The paper presents a shape and grade of inserts depending on the surface roughness of the intermetallic coatings NiAl and Ni3Al. Intermetallic coatings on nickel based were sprayed with a torch Casto-Dyn 8000 on the steel samples. Thermal spraying intermetallic coatings have been high surface roughness, and therefore they must to be finishing. Experimental research was conducted for unalloyed steel samples with thermal spraying NiAl and Ni3Al intermetallic coatings. Before applying coatings, the samples surface was properly prepared by stream abrasive working, degreasing and finally by cleaning of oxidation products. To testing cutting inserts shape selects square and trigon made tungsten carbide and cubic boron nitride (borazon). Machining intermetallic nickel based coatings were carried out for the cutting speed vc = 214 m/min in the case of after-machining with inserts of borazon, vc = 107 m/min cutting inserts for tungsten carbide, used feed fn = 0.06 mm/rev and depth of cut ap = 0.3 mm. Intermetallic coatings are characterized by high resistance to tribology wear. These materials are used in such fields of technology, such as: electronics, energy, defense, automotive, aviation, shipbuilding, and more industry. The NiAl and Ni3Al intermetallic have found widespread applications as high – temperature structural material due to their high melting point, low density, good thermal conductivity and excellent oxidation resistance. The paper proposes the finishing flame sprayed intermetallic coatings.

2

TEM Microstructure of Fe-Al Coatings Detonation Sprayed Onto Steel Substrate

Senderowski C., Pawłowski A., Bojar Z., Wołczyński W., Faryna M., Morgiel J., Major Ł.

Archives of Metallurgy and Materials

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2010

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Vol. 55, iss. 2

373-381

EN

The microstructure analysis of Fe-Al intermetallic coating deposited by detonation-gaseous spraying (DGS) on the 045 carbon steel substrate was presented in the paper. The microstructure was investigated using scanning (SEM) and transmission (TEM) electron microscopy, as well as selected area electron diffraction (SAED) techniques. The chemical concentration in microareas was revealed using the energy dispersive X-ray (EDS) spectroscopy technique. The TEM technique was applied to the analysis across the coating as well as close to the coating/substrate interface. The vicinity of the substrate was composed of an amorphous phase and columnar crystals as a result of rapid solidification of the partially melted FeAl powder. The Fe3Al phase was identified inside the coating, while at its surface Fe2Al5, Fe3Al and FeCrAl phases were found. Their occurrence and also the FeAl2O4 phase and aluminium oxide were confirmed by the X-ray diffraction method.

PL

W pracy przedstawiono analizę mikrostruktury powłoki międzymetalicznej faz typu Fe-Al naniesionej przez natryskiwanie detonacyjno-gazowe (DGS) na podłoże ze stali węglowej 045. Analizę tą przeprowadzono na podstawie badań metodą skaningowej (SEM) i transmisyjnej mikroskopii elektronowej(TEM). Metodą TEM analizowano budowę powłoki zarówno w głębi jak i w pobliżu granicy z podłożem. W sąsiedztwie podłoża stwierdzono fazę amorficzną oraz kryształy kolumnowe jako rezultat szybkiego krzepnięcia nadtopionej części proszku FeAl. W głębi powłoki zidentyfikowano fazy Fe3Al, zaś na jej powierzchni fazy Fe2Al5 i Fe3Al oraz FeCrAl. Występowanie tych faz oraz FeAl2O4 i tlenku glinu potwierdzono metodą dyfrakcji rentgenowskiej.

3

Residual stresses determined by the modified Sachs method within a gas detonation sprayed coatings of the Fe-Al intermetallic

Senderowski C., Bojar Z., Wołczyński W., Roy G., Czujko T.

Archives of Metallurgy and Materials

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2007

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Vol. 52, iss. 4

569-578

EN

A modified Sachs method was applied to determine the residual surface stress in Fe-Al type intermetallic coatings deposited on a surface of carbon 1045 steel substrate by a gas detonation spray technique. The detailed theoretical model with a description of device is presented. Compressive stresses in the entire thickness of created coatings is discussed. The influence of chemical composition of powders (applied for coating deposition) on residual stress related to the structural and phase composition, as well as the degree of chemical heterogeneity of the multilayer composite coating system is analyzed. The maximum amplitude of stress on the surface of coatings is within the range of -900 to -1100 MPa for samples without boron additive and between -500 and -600 MPa for samples with boron only. The composition of the powder blend of the FeAl-intermetallic coatings deposited on the surface of the substrate affects significantly the distribution of residual stresses. The structural inhomogeneity and no repeatability of physical and chemical properties of particular structural elements are the reasons for the development of residual stresses system generation within the coating.

PL

Zastosowano zmodyfikowaną metodę Sachsa, by określić stan rozkładu naprężeń własnych w głąb kolejnych warstw strukturalnych międzymetalicznych powłok typu Fe-Al, naniesionych metodą detonacyjną na stal węglową 45. Szczegółowo przedstawiono teoretyczny model obliczeniowy z opisem urządzenia pomiarowego. Stwierdzono obecność naprężeń ściskających w całej grubości badanych powłok. Analizowano wpływ składu chemicznego proszków (zastosowanych do otrzymania powłok) na naprężenia własne wielowarstwowego kompozytowego systemu powłokowego, określając właściwości strukturalne, skład fazowy, jak również stopień niejednorodności składu chemicznego powłok. Stwierdzono, że maksymalna wartość naprężeń własnych (-900 i -1100 MPa) występuje bezpośrednio w strefie przypowierzchniowej powłok bez udziału boru i nieco mniejsze wartości z przedziału (-500 i -600 MPa) odnotowano dla powłok z dodatkiem boru. Wykazano, że skład chemiczny proszków użytych do natryskiwania detonacyjnego, wpływa na rozkład naprężeń własnych powłok międzymetalicznych typu Fe-Al natryskiwanych na podłoże stalowe. Stwierdzono, że również niejednorodność strukturalna, a w efekcie niepowtarzalność właściwości fizyko-chemicznych poszczególnych składników strukturalnych powłok, są bezpośrednią przyczyną generowania określonego układu naprężeń własnych w badanych powłokach.

4

High temperature oxidation-resistant intermetallic coatings sputter-deposited on timetal 834

Moskalewicz T., Wendler B., Czyrska-Filemonowicz A.

Advances in Materials Science

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2007

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Vol. 7, nr 3(13)

80-85

EN

The microstructure and properties of the intermetallic Ti-Al-Ag and Ti-Al-Si-Ag coatings produced on Timetal 834 by magnetron sputtering have been examined. Phase identifications of the coatings were performed by advanced analytical transmission electron microscopy methods on cross-section thin foils prepared by focused ion beam miller. The TEM investigations revealed that both intermetallic coatings are composed from two different sublayers: outer columnar and inner amorphous. It has been found that the scale formed on the surface treated alloy during oxidation at 800°C for 200 h consisting of the inner TiO2 and outer AI2O3 sublayers.

5

Factors influencing abrasive wear of gas detonation sprayed FeAl - based intermetallic coatings

Senderowski C., Bojar Z.

International Journal of Applied Mechanics and Engineering

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2004

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Vol. 9, no spec.

65-71

EN

Gas detonation sprayed (GDS) intermetallic coatings made of Fe-Al phases are expected to be resistant to abrasive wear and may find tribological use in aggressive environments and / or at elevated temperature. Powder mixtures of Fe-Al type intermetallic phases were gas detonation sprayed on a plain carbon steel substrate to obtain protective coatings. It has been found that layered coatings structure consists of FeAl, Fe3Al and FeAl2 phases mixture with minimal content of pores. Metallographic examination of chemical and phase compositions of GDS coatings were carried out with Philips XL-30 scanning microscope integrated with DX4i - EDAX. The porosity of coatings was measured by quantitative metallography method using SIS image analyser integrated with SEM. Phase analysis of GDS coatings was performed by X-ray diffraction (XRD). Abrasion wear resistance of the GDS coatings was evaluated in tribological tests with plane - backward motion of the intermetallic coating - cast iron counter body couples. It has been found that layered structure of coating based on FeAl solid solution gives a wide range of possibilities of chemical composition changes. It has an influence on a high level of hardening, low porosity and a good adhesion of the coating. A significant difference has been observed between Fe-Al based GDS intermetallic coatings, bulk Fe3Al intermetallic alloy and alloyed cast iron behaviour during abrasion tests. The weight loss of investigated GDS coatings was about twenty five times lower than obtained for a bulk intermetallic sample and much more lower in comparison to alloyed cast iron tested under the same conditions. Finally, it was stated that high mean value of microhardness (700-800HV 0,1), lamellar microstructure, different level of aluminium and oxygen content in intermetallic phases, a small amount of Al2O3 oxide particles, high compressive stress and very low porosity were main factors determining very high abrasive wear resistance of Fe-Al based GDS intermetallic coatings.