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1

The influence of production method on oxidation resistance of the aluminide coatings obtained on IN 100 alloy

Pytel M., Góral M., Maliniak M.

Archives of Materials Science and Engineering

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2012

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Vol. 53, nr 2

102-108

EN

Purpose: The comparison of three deposition of coatings method. Design/methodology/approach: The diffusion aluminide coatings were deposited using the pack cementation, out of pack and CVD method. Findings: The authors present in the article the results on influence of the method of manufacturing the aluminide coatings on their microstructure and oxidation resistance. Research limitations/implications: The thickness analysis and the chemical composition analysis with a use of light microscopy, scanning electron microscopy and EDS analysis were performed. Practical implications: This process can be used in aerospace industry to form oxidation resistant coatings. Originality/value: It has been proven, that the coating obtained with CVD method, despite its small thickness, was characterized by the best cyclic oxidation resistance.

2

Long-term development directions of PVD/CVD coatings deposited onto sintered tool materials

Dobrzańska-Danikiewicz A., Gołombek K., Pakuła D., Mikuła J., Staszuk M., Żukowska L.

Archives of Materials Science and Engineering

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2011

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Vol. 49, nr 2

69-96

EN

Purpose: The purpose of this article is to evaluate strategic development perspectives of physical/ chemical vapour deposition of monolayer, multilayer and gradient coatings onto sintered tool materials with cemented carbides, cermets and tool ceramics substrates. The coating type was adopted as the criterion for technology division, thus obtaining eight technology groups for carried out research. Design/methodology/approach: In the framework of foresight-materials science research: a group of matrices characterising technology strategic position was created, materials science experiments using high-class specialised equipment were conducted and technology roadmaps were prepared. Findings: High potential and attractiveness were shown of the analysed technologies against the environment, as well as a promising improvement of mechanical and functional properties as a result of covering with the PVD/CVD coatings. Research limitations/implications: Research pertaining to covering sintered tool materials with the PVD/CVD coatings is part of a bigger research project aimed at selecting, researching and characterizing priority innovative material surface engineering technologies. Practical implications: The presented results of experimental materials science research prove the significant positive impact of covering with the PVD/CVD coatings on the structure and mechanical properties of sintered tool materials, which leads to the justification of their including into the set of priority innovative technologies recommended for application in industrial practice. Originality/value: The advantage of the article are results of comparative analysis of sintered tools materials with different types of coatings deposited in the PVD/CVD processes together with the recommended strategies of conduct, strategic development tracks and roadmaps of these technologies.

3

Application of artificial neural networks in properties modelling of PVD and CVD coatings

Dobrzański L.A., Staszuk M., Honysz R., Honysz R.

Archives of Computational Materials Science and Surface Engineering

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2010

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Vol. 2, nr 3

141-148

EN

Purpose: The aim of this paper is to describe the application of artificial neural networks in development of a model, which describes the influence of PVD and CVD coatings properties on the cutting edge durability from sintered carbides covered with these layers. Design/methodology/approach: The input data used for the artificial neural networks were PVD and CVD coatings microhardness, thickness, grain size and their adhesion to the substrate. On the network's output is the durability of the PVD and CVD coatings coated on sintered carbide blades determined in technological cutting trials of grey cast iron. Findings: Research results shows, that the greatest influence on the durability of coated sintered carbide blades is adhesion to the substrate. Smaller influence on blades durability has the size of grains. Other properties have a minor influence on the cutting tool. Practical implications: The presented results indicates, that the coating material selection and design of PVD and CVD coatings deposition process should be implemented with taking into consideration in the first place the best coating's adhesion to the substrate. Originality/value: The application of artificial neural networks for influence determination of PVD and CVD coatings microhardness, grain size, thickness and adhesion to the substrate on the durability of the sintered carbide blades covered with investigated coatings.

4

Thermal diffusivity of RE2Zr2O7 - type ceramic powders intended for TBCs deposited by APS

Moskal G., Witala B., Rozmysłowska A.

Archives of Materials Science and Engineering

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2009

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Vol. 36, nr 2

76-81

EN

Purpose: The aim of this paper is to provide overall characteristics of the Laser-Flash method and to determine the thermal diffusivity of powders intended for thermal spraying of thermal barrier coatings (TBC) of new type by air plasma spray (APS). Lanthanum, samarium, neodymium and gadolinium zirconates based powders with a pyrochlore structure and a general formula RE2Zr2O7 were used as the research material. Design/methodology/approach: The scope of the study encompassed thermal diffusivity tests of zirconium powders with the laser-flash method using the Netzsch LFA 427 apparatus for direct measurement of diffusivity. The scope of measured temperature ranged from 25°C to 1000°C (25, 250, 500, 750 and 1000°C). Every measurement point was repeated three times in order to obtain an average value. Findings: The studies conducted have enabled determining the value of thermal diffusivity of the material analyzed in the form of powder within a wide range of temperature. Research limitations/implications: The studies conducted suggest the necessity for verification of the obtained results for analogical coatings of the TBC type in order to determine the influence of the spraying process on the thermal diffusivity of the powders examined. Practical implications: The research results obtained provide a basis for further research on the base material and in particular, on the influence of porosity on thermal diffusivity. Originality/value: The original value presented in the paper is the information regarding the new type of ceramic materials intended for thermal spraying of TBCs.

5

Criteria of assessment of powders provided to spray by the APS method for new and conventional layers type TBC

Moskal G.

Archives of Materials Science and Engineering

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2009

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Vol. 37, nr 1

29-36

EN

Purpose: Verification of up-to-now use of conventional powders, provided to spray by the APS method for layers type TBC and its possible adaptation to layers of new types, which are based on new ceramic compounds, sprayed on conventional high temperature creep resisting alloys. New types of used ceramic powders are so called pyrochlores of the RE2Zr2O7 general formula. Design/methodology/approach: A scope of investigations comprised review of up-to-now used criteria of assessment and verification of them on powders of new types. Investigations of chemical composition were realized, in consideration of carbon and sulphur contents and gas oxygen and nitrogen contents. Investigations on sizes of powders by a sieve method and investigations on surface morphology were carried out. Assessment of microstructure, considering homogeneity in chemical composition and porosity, was carried out. Assessment of phase contents of exemplary powders was carried out. Findings: The carried out analysis enabled to compare criteria of assessment for two types of powders, provided to be sprayed by the APS method. It was stated that up-to-now used criteria of assessment of powders were correct also for materials of new types. Research limitations/implications: The carried out investigations suggest a necessity to verify results also on an example of another type of new powders. Practical implications: The got results reveal a possibility to use up-to-now procedures in assessment of powders for materials of a new type, completed with characteristics of physical and mechanical properties. Originality/value: Information concerning basic principles in assessment of properties microstructure of powders of a new type is an original value, presented in the article.

6

Carbon and titanium based layers for wood-based materials

Kaczorowski W., Batory D.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 27, nr 2

187-190

EN

Purpose: The main purpose of this work was to work out the technology of manufacturing carbon and titanium based layers on the surfaces of sintered carbides machining edges used in furniture industry. Design/methodology/approach: A hybrid deposition system employing DC magnetron sputtering and radio frequency plasma assisted chemical vapour deposition (RF PACVD) in one reaction chamber was used to manufacture Ti:C gradient layers. For the laboratory investigation layers were deposited on sintered carbide samples. Friction coefficient and SEM EDS analysis were made. For the exploitation tests layers were deposited on the commercial sintered carbide tools widely used in furniture industry. Findings: As the result of investigation it was noticed that Ti and C based gradient layers deposited on sintered carbides surfaces seems to be a very interesting alternative for standard non modified machining tools because of they noticeably decreased friction coefficient and improved durability. Practical implications: Presented technology is dedicated for furniture industry as a layer improving the cutting properties of the machining tools Originality/value: Application of carbon and titanium based layers deposited by hybrid deposition method on sintered carbide cutting edges for wood and wood-based materials machining.

7

The porosity assessment of thermal barrier coatings obtained by APS method

Moskal G.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 20, nr 1-2

483-486

EN

Purpose: The article presents the outline of methods and range of microstructural assessment of ceramic coatings, using the example of thermal barrier coatings. The major structural parameters describing the quality of the barrier layers have been characterised as well as the problems related to the correct metallographic specimen preparation and the methodology of their assessment. Design/methodology/approach: A procedure of porosity assessment, employing quantitative metallographic principles and authomatic image analysis has been propounded, together with types of quantitative parameters and methods of their application. Findings: It was found that the application of the quantitative metallographic methods combined with automatic image analysis can form an effective tool of both quantitative and qualitative assessment such parameters of structural ceramic layers as porosity. Research limitations/implications: This type of assessment enables obtaining more than just the absolute value of the porosity of the given area: it provides the means for determining a number of other qualitative parameters, e.g. the surface area of the pores, their elogation and shape together with the whole statistical analysis. Practical implications: The application of scanning microscopy, especially observation techniques such as BSE, BSETOPO or BSE3D enables a precise differentiation of the areas constituting pores from other artefacts. Originality/value: Description of procedure of porosity assessments in APS TBC system by the use of the quantitative metallographic methods combined with automatic image analysis, and possibility of applications special techniques of scanning microscopy.

8

Microstructure and oxidation behaviour of TiAlSi coatings on TiAlCrNb alloy

Moskal G.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 20, nr 1-2

263-266

EN

Purpose: Influence of slurry coating deposition TiAlSi with different Si concentration on oxidation resistance of Ti48Al2Cr2Nb intermetallic alloy and investigation of the influence of Si addition on the structure of obtained coatings. Design/methodology/approach: The research allowed the identification of microstructural changes that take place during oxidation test of TiAlSi coating during isothermal oxidation at 900 degrees centigrade for 500 h of exposure in air. The scope of the research encompassed a microstructural analysis with the use of macro and micro investigation - LM, SEM microscopy, XRD phases analysis and EDS analysis. Findings: The investigation has shown that the thickness of the coatings TiAlSi was in range from 30 to 40 mm. The structure of the silicon-modified aluminide coatings is as follows: the outer zone consisting of TiAl3 phase and titanium silicides/the middle zone consisting of columnar titanium silicides in phase TiAl3 matrix/the inner zone consisting of TiAl2 phase. In oxidation test, the much smaller increase of the mass has been observed, as a result of the coating deposition. The smallest mass changes have been detected in samples containing the coatings formed from 12.5% Si slurries. Research limitations/implications: The discussed research proves that main reason of much better oxidation resistance of TiAlSi coated base alloy is related to rich in aluminium TiAl3 phase presents in coating modified by Si. In addition silicon decrease activity of titanium, and in consequence the susceptibility of Al to selective oxidation is much stronger. The presents of Si due to Ti-Si phase generation with high oxidation resistance. Practical implications: The slurry method can be applied in aerospace and automotive industry as low-cost technology of producing of aluminide coatings on intermetallics. Originality/value: New method of aluminide coatings deposition on TiAl alloys.

9

Mechanical properties of the PVD gradient coatings deposited onto the hot work tool steel X40CrMoV5-1

Lukaszkowicz K., Dobrzański L. A., Pancielejko M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 2

115-118

EN

Purpose: The aim of the research is the investigation of the mechanical properties of gradient coatings deposited by PVD technique (cathodic arc evaporation method) onto the substrate from the X40CrMoV5-1 hot work steel. Design/methodology/approach: The microhardness tests were made on the dynamic ultra-microhardness tester. Tests of the coatings' adhesion to the substrate material were made using the scratch test. The wear and friction tests were performed on a standard pin-on-disc device. Findings: The hard PVD gradient coatings deposited by cathodic arc evaporation method demonstrate the high hardness, adhesion and wear resistance. The critical load LC2, which is in the range 46-59 N, depends on the coating type. The friction coefficient for the investigated coatings is within the range of 0.30-0.90. Research limitations/implications: In order to evaluate with more detail the possibility of applying these coatings in tools steel, further investigations should be concentrated on the determination of the mechanical and tribological properties of the coatings. Originality/value: It should be stressed that the mechanical properties of the PVD coatings obtained in this work are very encouraging and therefore their application for products manufactured at mass scale is possible in all cases where reliable, very hard and abrasion resistant coatings, deposited onto tools steel substrate are needed.

10

Measurement of residual stress in plasma-sprayed TBC with a gradient of porosity and chemical composition

Moskal G., Swadźba L., Rzychoń T.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 23, nr 2

31-34

EN

Purpose: The purpose of the research was identification of the residual stress in the top coat of different type of thermal barrier coating with gradient of chemical composition and gradient of porosity. Design/methodology/approach: The APS technique was used to deposition of gradient coating. As a bond coat the NiCrAlY overlay coating was applied. Top-coat consist in the case of gradient of porosity - YSZ with different thickness and porosity and in the case of chemical composition gradient YSZ with AMDRY 365-2 powder. The research allowed the identification of qualitative and quantitative phase constitution of top coat and residual stress measurement by sin square Psi method form surface of coatings. Findings: It was found that the dominant phase in all the top coats was tetragonal zirconia with minor addition of monoclinic type of ZrO2 and in the case of residual stress the tensile conditions was observed in the case of gradient porosity and compressive stresses in the case of chemical gradient. Research limitations/implications: Characterization of stress level in gradient TBC's give possibility description of degradation mechanism of barrier coating. Practical implications: The results obtained allow the determination of the degree of life-time lost of the TBC system used as protection for creep resistant alloys. Originality/value: The results obtained are valuable contribution to the development of new type of TBC. They enable the identification of the degradation mechanisms in YSZ / MCrAlY / substrate system.

11

Effect of TBC on oxidation behaviour of gamma-TiAl based alloy

Moskal G.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 22, nr 2

31-34

EN

Purpose: The purpose of the research was identification of the influence of TBC coating system on oxidation resistance of TiAl based alloy during oxidation at temperature of 900 and 950 degrees centigrade for 500 h and 200 h respectively. Design/methodology/approach: The APS technique was used to modify and improvement of oxidation resistance of TiAl intermetallic alloy. As a bond coat the NiCrAlY overlay coating was applied. The bond-coat provided a good bonding strength between matrix and ceramic top coat. The research allowed the identification of microstructural changes that take place between top coat and bond coat and bond coat and substrate. The examinations were conducted on specimens after 200 h and 500 h of exposition at 950 and 900 degrees centigrade. Findings: It was found that the surface conditions of basic alloy is electively protected by used type of ceramic coating. The basic alloy exhibited poor oxidation resistance at this range of temperature due to formation of mixed Al2O3 + TiO2 scale which is easily spalled off. A ceramic top coat together with bond coat can be effectively coated on the surface of TiAl basic alloy by APS method. Oxidation test both at 900 and 950 degrees centigrade showed that oxidation resistance of APS coated 48-2-2 alloy was improved. Research limitations/implications: Application of TBC remarkably improve the oxidation resistance of TiAl basic alloy due to lowering temperature of the substrate surface and due to formation of dense alumina sublayer (TGO) on the top surface of bond coat which can prevent diffusion processes of titanium and oxygen. Practical implications: The results obtained allow the determination of the degree of life-time lost of the TBC system used as protection for titanium aluminides alloys. Originality/value: The results obtained are valuable contribution to the development of new type of TBC for TiAl alloys. They enable the identification of the degradation mechanisms in YSZ/MCrAlY/substrate system.

12

Characterisation of air plasma sprayed TBC coating during isothermal oxidation at 1100 degrees centigrade

Swadźba L., Moskal G., Mendala B., Gancarczyk T.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 21, nr 2

81-84

EN

Purpose: The purpose of the research was characterization of failure modes of air plasma sprayed thermal barrier coatings system in isothermal oxidation test conditions at 1100 degrees centigrade. Design/methodology/approach: The research allowed the identification of microstructural changes that take place during oxidation test of TBC system in area of ceramic top-layer, bond coat and superalloy substrate. The examinations were conducted on specimens after 50, 120, 500, 1000, 1500 and 2000 h of exposition. The scope of the research encompassed a microstructural analysis with the use of macro and micro investigation - LM, SEM microscopy. Findings: It was found that the lifetime of commercially quality TBC system is related to progress of degradation in area of bond coat and ceramic top layer. During isothemal oxidation, the bond coat in the TBCs was oxidized to form an alumina and a mixed oxide layer between the top coat of yttria stabilised zirconia (YSZ) and bond coat of NiCoCrAlY alloy. At the moment of oxidation acceleration, the cracks initiation and propagation was observed in the mixed oxide layer near the YSZ. The crack propagation inducted the delamination and spallation of top coat after 1000 h oxidation. Research limitations/implications: The discussed research proves that main reason of degradation in TBC system is related to progressive development of cracks at the interface of the thermally grown oxide with bond coat, within the top coat or at its interface with TGO. Practical implications: The results obtained allow the determination of the degree of life-time lost of the investigated TBC system and specification of the time of safety operation. Originality/value: The results obtained are valuable contribution to durability characterization of TBC systems. They enable the identification of the degradation mechanisms, which enhances the durability and safety of high temperature operation.

13

Advanced materials and protective coatings in aero-engines application

Hetmańczyk M., Swadźba L., Mendala B.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 1

372-381

EN

Purpose: The following article demonstrates the characteristics of the materials applied as parts of aircraft engine turbines and the stationary gas turbines. The principal technologies for manufacturing the heat resistant coatings and the erosion and corrosion resistant coatings were characterized. Sample applications for the aforementioned coatings are presented: on turbine blades, compressor blades and on parts of combustion chambers of aircraft engines. Design/methodology/approach: The nickel-based alloys were characterized. The following methods of depositing diffusion aluminide coatings were described: pack cementation, out of pack and CVD (chemical vapour deposition). The properties of thermal barrier coatings obtained by thermal spraying and physical vapour deposition (PVD) were presented. Findings: : The structures of aluminide and platinum modified aluminide coatings, which displayed higher heat resistance during the cyclic oxidation test, were presented. The structure of TBC coatings was described as well. During aircraft engine tests, the compressor blades with multilayer type Cr/CrN coatings exhibited higher wear resistance than the coatings covered with Ti/TiN. Research limitations/implications: The aluminide coatings were deposited on nickel-based superalloys, which are typically used to manufacture turbine blades for aircraft engines. The multilayer nitride coatings were produced by Arc-PVD method. Practical implications: All the described technologies and coatings find applications on parts of aircraft engines. Originality/value: The presented advanced technologies of manufacturing protective coatings on the parts of aircraft engines were developed by the authors of the following study as parts of their planned scientific research, research projects, and purpose projects.

14

Mechanical properties of multilayer coatings deposited by PVD techniques onto the brass substrate

Lukaszkowicz K., Dobrzański L. A., Zarychta A., Cunha L.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 15, nr 1-2

47--52

EN

Purpose: This research was done to investigate the mechanical properties of coatings deposited by PVD techniques onto brass substrate. Design/methodology/approach: The coatings were produced by reactive dc magnetron sputtering. The microstructure of the coatings was cross section examined using scanning electron microscope. The residual stress was obtained from the parabolic deflection of the samples, after the coating deposition applying Stoney’s equation. The microhardness and Young’s modulus tests were made on the dynamic ultra-microhardness tester. Tests of the coatings’ adhesion to the substrate material were made using the scratch test. Findings: Obtained results show that all the coatings are in a state of compressive residual stress. The lower values of the internal stresses in multilayer coatings result from the possibility of stress release in the successive alternating layers of the relatively soft titanium. Highest hardness values are obtained in monolayer coatings. The stiffness of the examined coatings is between 195 ÷ 330 mN/μm, while Young’s modulus is between 210 ÷ 348 GPa. Concerning the adhesion of the coatings measured by scratch test, it has been stated that the critical load LC2 for coatings, deposited onto the brass ranges from 40 to 50 N. The greatest critical load has been obtained for monolayer coatings. Research limitations/implications: In order to evaluate with more detail the possibility of applying these coatings in tools, further investigations should be concentrated on the determination of the tribological properties of the coatings. Practical implications: The tools and functional materials coated by the PVD process have shown significant improvement. Good properties of the PVD coatings make these coatings suitable for various technical and industrial applications. Originality/value: It should be stressed that the mechanical properties of the PVD coatings obtained in this work are very encouraging and therefore their application for products manufactured at mass scale is possible in all cases where reliable, very hard and abrasion resistant coatings, deposited onto brass substrate are needed.