Carl Quaeyhaegens - Academia.edu (original) (raw)
Papers by Carl Quaeyhaegens
Resources, Conservation and Recycling, 2011
Diamond and Related Materials, 1998
Nitrogen is one of the most widely studied impurities in diamond films. The reason is that nitrog... more Nitrogen is one of the most widely studied impurities in diamond films. The reason is that nitrogen takes part in a number of defects and therefore has a deep influence on the optical and electrical properties of diamond films. The mechanism of nitrogen incorporation in diamond is still an open question. This is mainly due to the complexity of the
Defect-induced optical absorption in diamond layers, homoepitaxially grown by the chemical vapour... more Defect-induced optical absorption in diamond layers, homoepitaxially grown by the chemical vapour deposition technique, is investigated by the use of photothermal deflection spectroscopy (PDS). The measured spectral dependence of the optical absorption coefficient for these layers is compared with the optical absorption in type IIa natural and type Ib synthetic diamond. The measured absorption spectra show the orientation-dependent nitrogen incorporation in the homoepitaxial diamond layers. The orientation-dependent nitrogen incorporation is in agreement with the cathodoluminescence data. The characteristic subgap continuum absorption is observed in both (001) and { 110) oriented diamond layers.
Surface and Coatings Technology, 1993
The interface between austenitic stainless steel AISI 304 and three different types of TiN coatin... more The interface between austenitic stainless steel AISI 304 and three different types of TiN coating, one with and two without an intermediate Ti layer, deposited using the triode evaporation ion plating technique, were characterized using cross-sectional transmission electron microscopy, glancing angle X-ray diffraction and resonant nuclear reaction analysis. A highly faulted interface due to the initial plasma nitriding of the substrates is observed for one type of deposition without the intermediate Ti layer. In this case a phase is formed at the interface between AISI 304 and the TiN coating, identified as expanded austenite. Scratch tests show poor coating adhesion of these samples. In contrast, a well adherent TiN coating can be deposited onto austenitic stainless steel without an intermediate Ti layer when the substrate material is not plasma nitrided and a defect-free interface is formed.
Surface and Coatings Technology, 1993
To improve the surface hardness of steel, the substrate can be plasma nitrided prior to the depos... more To improve the surface hardness of steel, the substrate can be plasma nitrided prior to the deposition of a TiN layer. The success of this combined treatment depends very strongly on the intermediate thermal treatments carried out between plasma nitriding and TiN deposition. In this paper, some additional steps carried out after plasma nitriding and prior to TIN deposition, have been investigated to reveal the effect ofthe resulting interface on the adhesion of the coating. These combined treatments are carried out on austenitic stainless steel AISI 304 and on cold work tool steel 1.2379. If the plasma-nitrided steel surface is only coated with a thin Ti intermediate layer before the deposition of the TiN layer 1.5~imthick-as it is usually the case for a standard TiN coating-flaking of the TiN coating is observed with AISI 304, even if no external load is applied. For the cold work tool steel, the TiN coating flakes when a small external load is applied in a scratch adhesion test. However, ifthe nitrided specimen is first cooled down, subsequently plasma heated and then sputter etched before the deposition ofthe Ti-TiN layer, no flaking is observed for both steel types. X-Ray diffraction (XRD) measurements and a transmission electron microscopy (TEM) study are carried out to reveal the interfacial phases which could cause this different behaviour. Scratch tests are carried out to correlate the adhesion of the TiN coating for different intermediate treatments with the results of the XRD and TEM studies.
Surface and Coatings Technology, 1996
Combining TiN coating deposition by PVD and nitriding by nitrogen implantation in stainless steel... more Combining TiN coating deposition by PVD and nitriding by nitrogen implantation in stainless steels shows promise for the future if a good adhesion between the coating and the substrate can be obtained. It is therefore necessary to study the structure and composition of the nitrided surface with a view to optimizing the coating adhesion. Implantation of nitrogen at doses of l-5 x 1Or7 N' cm-' and with an energy of 50 keV was realized in the nitriding of AISI 304 and AISI 310 austenitic stainless steels. Some samples were heated in vacua to 400 "C after implantation to simulate the temperature effect during PVD coating. Conversion electron Misssbauer spectroscopy (CEMS) and transmission electron microscopy (TEM) were used to investigate the nitride phases due to nitrogen implantation. These measurements confirm previous results obtained by X-ray diffraction (XRD) and by resonant nuclear reaction analysis (RNRA). CEMS shows an evolution in the phases formed after implantation. At low doses, a solid solution in austenite was formed while a a-(Fe, Cr, Ni),,, N nitride was formed at higher doses. For the 2 x 1Ol7 Ni cmm2 implanted and post-heated sample, CEMS and TEM gave evidence for the presence of a nitrogen solid solution and confirmed the diffusion of nitrogen deep into the specimen.
Thin Solid Films, 1999
The mechanisms of nitrogen incorporation in diamond are still an unsolved riddle. This is mainly ... more The mechanisms of nitrogen incorporation in diamond are still an unsolved riddle. This is mainly due to the complexity of the processes involved as they not only depend on empirical parameters (e.g. vessel pressure, substrate temperature, the gas phase composition, type and concentration of the nitrogen containing compound used), but also on the plasma chemistry and the surface chemical reactions. In this study, small quantities (ppm range) of diatomic nitrogen are added to a conventional hydrogen-methane feed gas mixture in order to investigate the effect of nitrogen incorporation in diamond films prepared by microwave plasma assisted chemical vapour deposition (CVD). Optical emission spectroscopy (OES) is used to survey the plasma composition during deposition. The intensities of the CN, CH and C2 emitting radicals and the Balmer atomic hydrogen emission lines are correlated to the Raman film quality and to the nitrogen content in the film measured by secondary ion mass spectrometry (SIMS).
Thermochimica Acta, 1998
In view of the study of the chemistry of the oxalate coprecipitation process for preparing BiSrCa... more In view of the study of the chemistry of the oxalate coprecipitation process for preparing BiSrCaCuO superconductors, the characteristics of oxalates of calcium and strontium in the Ca(NO3)2–Sr(NO3)2–HNO3–H2O–(NH4)2C2O4 system are investigated. Based on XRD, SEM and TG a comparison between the crystal structure, morphology and thermal decomposition behavior of coprecipitated and physically mixed calcium and strontium oxalates with the same
Surface and Coatings Technology, 1999
ABSTRACT Plasma properties related to TiN deposition are compared in two triode ion-plating syste... more ABSTRACT Plasma properties related to TiN deposition are compared in two triode ion-plating systems (System A and System B) using a low-voltage arc discharge. System A employs a magnetic field, confining the arc and the plasma, while System B does not. The systems also differ in the configuration of the chamber.TiN coatings are deposited in both systems over a range of negative bias voltages from 25 to 150V. A correlation is established between the coating properties and the plasma parameters determined by energy-resolved mass spectrometry.The plasma potential in System B is between +15 and +35V, featuring a spatial inhomogeneity. System A exhibits a higher plasma potential (about +55V), resulting in higher energies of ions at substrates and a narrower energy distribution of ions. Unlike in System B, the population of Ti2+ in System A is even higher than that of Ti+. The presence of high-energy neutral Ti is observed.The texture coefficients and the stress-free lattice parameters measured by X-ray diffraction on TiN films deposited at negative substrate bias in the range from 25 to 150V behave similarly in both deposition systems but with a shift in bias necessary for similar properties. The appropriate bias in System B is about 75V higher than in System A. This shift corresponds to the difference between the systems in the plasma potential and the degree of ionisation found by energy-resolved mass spectrometry.Other film properties, especially the film compressive stress, microhardness, critical load in scratch tests and the surface roughness, remain almost constant over the whole range of bias values in both systems. This means that these properties are less sensitive to ion bombardment in the triode ion-plating systems under the conditions studied.
Surface and Coatings Technology, 1991
MET WORKING IND,CTR SCI & TECH,B-3610 DIEPENBEEK,BELGIUM.QUAEYHAEGENS, C, LIMBURGS UNIV CENTR... more MET WORKING IND,CTR SCI & TECH,B-3610 DIEPENBEEK,BELGIUM.QUAEYHAEGENS, C, LIMBURGS UNIV CENTRUM,MAT PHYS RES GRP,UNIV CAMPUS,B-3610 DIEPENBEEK,BELGIUM.
Surface and Coatings Technology, 1993
This paper deals with the influence of the nitrogen flow rate on the microstructure of 6-TiNs fil... more This paper deals with the influence of the nitrogen flow rate on the microstructure of 6-TiNs films prepared by d.c. magnetron sputtering. The 6-TiN, films were prepared under decreasing nitrogen flow rates to obtain nitrogen Contents in the films ranging from v = 0.99 to 0.95. Ion bombardment of the films was negligible in these experiments. Some films prepared under deposition conditions which typically result in a fine-grain (about 0.1 jim) transition zone microstructure exhibit a "large"-grain (about I jim) zone Ill mierostructure. It has been demonstrated that there exists a narrow area of nitrogen flow rate for which the microstructure of the films does not agree with the zone model. The large-grain films are stress free. The nitrogen content in the films containing large grains is x = 0.97. All deposition conditions except the nitrogen flow rate were kept constant in this experiment. Chemical energy dissipated during the reactive process can explain the observed effects.
Surface and Coatings Technology, 1998
A method for determination of the effective diffusion coefficient and sputtering rate in plasma d... more A method for determination of the effective diffusion coefficient and sputtering rate in plasma diffusion treatment of material~ is presented. The method is based on a previosuiy proposed plasma nitriding diffusion model, where the nitrided layer thickness as a function of time is the main input data for determination of the nitrogen diffusion coefficient. The method is compared with the results of determination of diffusion coefficients in plasma nitrided austenitic stainless steels as received by the internal nitriding model, which is analogous to the internal oxidation model. It is demonstrated that the method predicts the correct temperature dependence of the nitrogen diffusion coefficient contrary to the internal nitriding model. The calculated sputtering rate is in good agreement with that estimated in the frame of Thornton's ion plating model © 1998 Elsevier Science S.A.
Surface and Coatings Technology, 1995
Ti2N coatings are very interesting for corrosion and wear-resistance applications. It seems, howe... more Ti2N coatings are very interesting for corrosion and wear-resistance applications. It seems, however, that their introduction in industry has failed owing to insufficient reproducibility and scale-up problems. In this paper, a number of deposition experiments are described in which the evaporation ion plating technique was used to study the influence of the Ti evaporation rate and the deposition temperature on
Surface and Coatings Technology, 1994
ABSTRACT
Surface and Coatings Technology, 1994
Abstract The energetic distribution of ions in a triode ion plating configuration during TiN depo... more Abstract The energetic distribution of ions in a triode ion plating configuration during TiN deposition was investigated. The fluxes of different ions such as Ti + , N + , N + 2 , TiN + , TiAr + , impinging on the substrate, for various N partial pressures were measured by mass-energy spectrometry. The potential distribution in the plasma and the total ion flux towards the substrate were evaluated by Langmuir plasma probing. A model of the potential distribution in the triode ion plating plasma configuration is suggested and the Ti ionization for various plasma conditions is discussed.
Resources, Conservation and Recycling, 2011
Diamond and Related Materials, 1998
Nitrogen is one of the most widely studied impurities in diamond films. The reason is that nitrog... more Nitrogen is one of the most widely studied impurities in diamond films. The reason is that nitrogen takes part in a number of defects and therefore has a deep influence on the optical and electrical properties of diamond films. The mechanism of nitrogen incorporation in diamond is still an open question. This is mainly due to the complexity of the
Defect-induced optical absorption in diamond layers, homoepitaxially grown by the chemical vapour... more Defect-induced optical absorption in diamond layers, homoepitaxially grown by the chemical vapour deposition technique, is investigated by the use of photothermal deflection spectroscopy (PDS). The measured spectral dependence of the optical absorption coefficient for these layers is compared with the optical absorption in type IIa natural and type Ib synthetic diamond. The measured absorption spectra show the orientation-dependent nitrogen incorporation in the homoepitaxial diamond layers. The orientation-dependent nitrogen incorporation is in agreement with the cathodoluminescence data. The characteristic subgap continuum absorption is observed in both (001) and { 110) oriented diamond layers.
Surface and Coatings Technology, 1993
The interface between austenitic stainless steel AISI 304 and three different types of TiN coatin... more The interface between austenitic stainless steel AISI 304 and three different types of TiN coating, one with and two without an intermediate Ti layer, deposited using the triode evaporation ion plating technique, were characterized using cross-sectional transmission electron microscopy, glancing angle X-ray diffraction and resonant nuclear reaction analysis. A highly faulted interface due to the initial plasma nitriding of the substrates is observed for one type of deposition without the intermediate Ti layer. In this case a phase is formed at the interface between AISI 304 and the TiN coating, identified as expanded austenite. Scratch tests show poor coating adhesion of these samples. In contrast, a well adherent TiN coating can be deposited onto austenitic stainless steel without an intermediate Ti layer when the substrate material is not plasma nitrided and a defect-free interface is formed.
Surface and Coatings Technology, 1993
To improve the surface hardness of steel, the substrate can be plasma nitrided prior to the depos... more To improve the surface hardness of steel, the substrate can be plasma nitrided prior to the deposition of a TiN layer. The success of this combined treatment depends very strongly on the intermediate thermal treatments carried out between plasma nitriding and TiN deposition. In this paper, some additional steps carried out after plasma nitriding and prior to TIN deposition, have been investigated to reveal the effect ofthe resulting interface on the adhesion of the coating. These combined treatments are carried out on austenitic stainless steel AISI 304 and on cold work tool steel 1.2379. If the plasma-nitrided steel surface is only coated with a thin Ti intermediate layer before the deposition of the TiN layer 1.5~imthick-as it is usually the case for a standard TiN coating-flaking of the TiN coating is observed with AISI 304, even if no external load is applied. For the cold work tool steel, the TiN coating flakes when a small external load is applied in a scratch adhesion test. However, ifthe nitrided specimen is first cooled down, subsequently plasma heated and then sputter etched before the deposition ofthe Ti-TiN layer, no flaking is observed for both steel types. X-Ray diffraction (XRD) measurements and a transmission electron microscopy (TEM) study are carried out to reveal the interfacial phases which could cause this different behaviour. Scratch tests are carried out to correlate the adhesion of the TiN coating for different intermediate treatments with the results of the XRD and TEM studies.
Surface and Coatings Technology, 1996
Combining TiN coating deposition by PVD and nitriding by nitrogen implantation in stainless steel... more Combining TiN coating deposition by PVD and nitriding by nitrogen implantation in stainless steels shows promise for the future if a good adhesion between the coating and the substrate can be obtained. It is therefore necessary to study the structure and composition of the nitrided surface with a view to optimizing the coating adhesion. Implantation of nitrogen at doses of l-5 x 1Or7 N' cm-' and with an energy of 50 keV was realized in the nitriding of AISI 304 and AISI 310 austenitic stainless steels. Some samples were heated in vacua to 400 "C after implantation to simulate the temperature effect during PVD coating. Conversion electron Misssbauer spectroscopy (CEMS) and transmission electron microscopy (TEM) were used to investigate the nitride phases due to nitrogen implantation. These measurements confirm previous results obtained by X-ray diffraction (XRD) and by resonant nuclear reaction analysis (RNRA). CEMS shows an evolution in the phases formed after implantation. At low doses, a solid solution in austenite was formed while a a-(Fe, Cr, Ni),,, N nitride was formed at higher doses. For the 2 x 1Ol7 Ni cmm2 implanted and post-heated sample, CEMS and TEM gave evidence for the presence of a nitrogen solid solution and confirmed the diffusion of nitrogen deep into the specimen.
Thin Solid Films, 1999
The mechanisms of nitrogen incorporation in diamond are still an unsolved riddle. This is mainly ... more The mechanisms of nitrogen incorporation in diamond are still an unsolved riddle. This is mainly due to the complexity of the processes involved as they not only depend on empirical parameters (e.g. vessel pressure, substrate temperature, the gas phase composition, type and concentration of the nitrogen containing compound used), but also on the plasma chemistry and the surface chemical reactions. In this study, small quantities (ppm range) of diatomic nitrogen are added to a conventional hydrogen-methane feed gas mixture in order to investigate the effect of nitrogen incorporation in diamond films prepared by microwave plasma assisted chemical vapour deposition (CVD). Optical emission spectroscopy (OES) is used to survey the plasma composition during deposition. The intensities of the CN, CH and C2 emitting radicals and the Balmer atomic hydrogen emission lines are correlated to the Raman film quality and to the nitrogen content in the film measured by secondary ion mass spectrometry (SIMS).
Thermochimica Acta, 1998
In view of the study of the chemistry of the oxalate coprecipitation process for preparing BiSrCa... more In view of the study of the chemistry of the oxalate coprecipitation process for preparing BiSrCaCuO superconductors, the characteristics of oxalates of calcium and strontium in the Ca(NO3)2–Sr(NO3)2–HNO3–H2O–(NH4)2C2O4 system are investigated. Based on XRD, SEM and TG a comparison between the crystal structure, morphology and thermal decomposition behavior of coprecipitated and physically mixed calcium and strontium oxalates with the same
Surface and Coatings Technology, 1999
ABSTRACT Plasma properties related to TiN deposition are compared in two triode ion-plating syste... more ABSTRACT Plasma properties related to TiN deposition are compared in two triode ion-plating systems (System A and System B) using a low-voltage arc discharge. System A employs a magnetic field, confining the arc and the plasma, while System B does not. The systems also differ in the configuration of the chamber.TiN coatings are deposited in both systems over a range of negative bias voltages from 25 to 150V. A correlation is established between the coating properties and the plasma parameters determined by energy-resolved mass spectrometry.The plasma potential in System B is between +15 and +35V, featuring a spatial inhomogeneity. System A exhibits a higher plasma potential (about +55V), resulting in higher energies of ions at substrates and a narrower energy distribution of ions. Unlike in System B, the population of Ti2+ in System A is even higher than that of Ti+. The presence of high-energy neutral Ti is observed.The texture coefficients and the stress-free lattice parameters measured by X-ray diffraction on TiN films deposited at negative substrate bias in the range from 25 to 150V behave similarly in both deposition systems but with a shift in bias necessary for similar properties. The appropriate bias in System B is about 75V higher than in System A. This shift corresponds to the difference between the systems in the plasma potential and the degree of ionisation found by energy-resolved mass spectrometry.Other film properties, especially the film compressive stress, microhardness, critical load in scratch tests and the surface roughness, remain almost constant over the whole range of bias values in both systems. This means that these properties are less sensitive to ion bombardment in the triode ion-plating systems under the conditions studied.
Surface and Coatings Technology, 1991
MET WORKING IND,CTR SCI & TECH,B-3610 DIEPENBEEK,BELGIUM.QUAEYHAEGENS, C, LIMBURGS UNIV CENTR... more MET WORKING IND,CTR SCI & TECH,B-3610 DIEPENBEEK,BELGIUM.QUAEYHAEGENS, C, LIMBURGS UNIV CENTRUM,MAT PHYS RES GRP,UNIV CAMPUS,B-3610 DIEPENBEEK,BELGIUM.
Surface and Coatings Technology, 1993
This paper deals with the influence of the nitrogen flow rate on the microstructure of 6-TiNs fil... more This paper deals with the influence of the nitrogen flow rate on the microstructure of 6-TiNs films prepared by d.c. magnetron sputtering. The 6-TiN, films were prepared under decreasing nitrogen flow rates to obtain nitrogen Contents in the films ranging from v = 0.99 to 0.95. Ion bombardment of the films was negligible in these experiments. Some films prepared under deposition conditions which typically result in a fine-grain (about 0.1 jim) transition zone microstructure exhibit a "large"-grain (about I jim) zone Ill mierostructure. It has been demonstrated that there exists a narrow area of nitrogen flow rate for which the microstructure of the films does not agree with the zone model. The large-grain films are stress free. The nitrogen content in the films containing large grains is x = 0.97. All deposition conditions except the nitrogen flow rate were kept constant in this experiment. Chemical energy dissipated during the reactive process can explain the observed effects.
Surface and Coatings Technology, 1998
A method for determination of the effective diffusion coefficient and sputtering rate in plasma d... more A method for determination of the effective diffusion coefficient and sputtering rate in plasma diffusion treatment of material~ is presented. The method is based on a previosuiy proposed plasma nitriding diffusion model, where the nitrided layer thickness as a function of time is the main input data for determination of the nitrogen diffusion coefficient. The method is compared with the results of determination of diffusion coefficients in plasma nitrided austenitic stainless steels as received by the internal nitriding model, which is analogous to the internal oxidation model. It is demonstrated that the method predicts the correct temperature dependence of the nitrogen diffusion coefficient contrary to the internal nitriding model. The calculated sputtering rate is in good agreement with that estimated in the frame of Thornton's ion plating model © 1998 Elsevier Science S.A.
Surface and Coatings Technology, 1995
Ti2N coatings are very interesting for corrosion and wear-resistance applications. It seems, howe... more Ti2N coatings are very interesting for corrosion and wear-resistance applications. It seems, however, that their introduction in industry has failed owing to insufficient reproducibility and scale-up problems. In this paper, a number of deposition experiments are described in which the evaporation ion plating technique was used to study the influence of the Ti evaporation rate and the deposition temperature on
Surface and Coatings Technology, 1994
ABSTRACT
Surface and Coatings Technology, 1994
Abstract The energetic distribution of ions in a triode ion plating configuration during TiN depo... more Abstract The energetic distribution of ions in a triode ion plating configuration during TiN deposition was investigated. The fluxes of different ions such as Ti + , N + , N + 2 , TiN + , TiAr + , impinging on the substrate, for various N partial pressures were measured by mass-energy spectrometry. The potential distribution in the plasma and the total ion flux towards the substrate were evaluated by Langmuir plasma probing. A model of the potential distribution in the triode ion plating plasma configuration is suggested and the Ti ionization for various plasma conditions is discussed.