Evaluation of the resistance to oxidation of niobium treated by high temperature nitrogen Plasma Based Ion Implantation

Oliveira, Rogério Moraes; Hoshida, Lilian; Oliveira, Aline Capella de; Silva, Matheus M.N.F.; Pichon, L.; Santos, Nazir Monteiro dos

doi:10.1016/j.surfcoat.2016.10.012

Cited by 9 publications

(7 citation statements)

References 14 publications

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“…The modification of the surface properties of the reentrant cavities was performed herein via HT-NPBII. This process was recently used to successfully treat Nb substrates for improving its mechanical and tribological properties 28 and to enhance its oxidation resistance as well 29 . For both cases, the formation of thick nitride layers, mandatory to reach those proposed goals, was attained thanks to the high substrate temperature adjusted during experiments.…”

Section: Methodsmentioning

confidence: 99%

The Surface Treatment of Niobium Superconducting Reentrant Cavities by Means of High Temperature Nitrogen Plasma Based Ion Implantation

et al. 2019

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High Temperature Nitrogen Plasma Based Ion Implantation (HT-NPBII) has been used to treat the surface of niobium superconducting reentrant cavities, which are part of parametric transducers in a resonant-mass gravitational wave detector. The aim is to enhance the corresponding electrical quality factors (Q-factors) which are closely related with the increase of the sensitivity of the system. In this experiment, the cavities are immersed in plasma and bombarded by energetic nitrogen ions, which are implanted into the surfaces of these heated substrates. The heating temperature of the cavities is controlled during the treatment and its level directly affects the N implantation depth profile due to the diffusion process. Additional tailoring of the nitrogen doping can be performed by the adjustment of the intensity and the duty cycle of the high negative voltage pulses used for ion implantation. For implantations performed at 5 kV /20 μs /300 Hz/ 700 °C, nitrogen atoms occupy interstitial spaces in the crystal lattice of niobium. The treatment of niobium superconducting cavities under these parameters caused the enhancement of two orders of magnitude of respective Q-factors. A set of characterization techniques was performed herein in order to help with the understanding of the underlying mechanism behind this phenomenon.

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Section: Methodsmentioning

confidence: 99%

The Surface Treatment of Niobium Superconducting Reentrant Cavities by Means of High Temperature Nitrogen Plasma Based Ion Implantation

et al. 2019

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“…Earlier works 40,41 studied the oxidation of NbN thin films, in this case it was found that as the oxygen rate increases after oxidation at 400° C, the nitrogen concentration decreases. Nb As noticed in previous works 17,42 , in high oxidation temperatures the aluminum atoms present in the NbAlN thin films microstructure diffuses into grain boundary and surface regions, forming amorphous Al 2 O 3 .…”

Section: Nanohardness Analysismentioning

confidence: 99%

Interrelation Among Morphology, Mechanical Properties and Oxidation Behavior of NbxAlyNz Thin Films

et al. 2019

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Nb x Al y N z thin films were deposited by magnetron sputtering reactive technique with (y/x+y) ratio varying from 0 to 0.4, in order to maintain aluminum atoms inside NbN matrix in solid solution. GAXRD analyses revealed that the crystalline phase obtained for Nb x Al y N z thin films was B1-NbN with a lattice constant shrinkage as Al concentration at these coatings was increased. Due to similarity in electro negativity values between Nb and Al, XPS analyses could not verify pronounced changes among as deposited Nb x Al y N z coatings. The average hardness values evidenced that solid solution strengthening mechanism did not increase hardness significantly. The oxidation resistance increased with Al content and no oxide phases were registered by GAXRD analyses for coating with more aluminum added. However, SEM images revealed bubbles after oxidation at high temperatures for all samples.

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“…us, improving the surface properties of niobium is necessary for its application at high temperatures in an oxidative environment [2]. e effectiveness of HT-NPBII for the treatment of metal alloys and refractory metals was reported in [3][4][5]. Details about this process can be found in [6].…”

Section: Introductionmentioning

confidence: 99%

“…e absorption of nitrogen under the influence of high temperature is magnified, leading to the formation of thick nitrided layers. In the case of Nb, the formation of nitrides in the upper layers of the metal can significantly improve its mechanical and tribological properties [4] as well as its oxidation resistance [3]. In fact, implantation of nitrogen into niobium at 1000°C and 1250°C via HT-NPBII led to the appearance of different phases of niobium nitrides (NbN, Nb 2 N, and Nb 4 N 3 ), which resulted in significant increase in hardness and wear reduction, besides causing a retard in the oxidation of the metal by about 130°C [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

The Influence of High‐Temperature Nitrogen Plasma‐Based Ion Implantation on Niobium Creep Behavior

Oliveira

Reis

Oliveira

et al. 2020

Advances in Materials Science and Engineering

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Niobium has been considered for applications in the aerospace sector, but its use at high temperatures is restricted, due to the great affinity of refractory metals with oxygen, which results in the formation of oxide layers and a decrease in their mechanical resistances. In the present work, Nb samples were submitted to High-Temperature Nitrogen Plasma-Based Ion Implantation (HT-NPBII). The process runs at a working pressure between 3 and 4 mbar and negative high voltage pulses of 7 kV/30 μs/300 Hz were applied to samples heated to 1000°C, at treatment times of 1 h, 4 h, and 8 h, respectively. Microstructural and mechanical characterizations of the treated samples revealed the formation of a layer of Nb2N, with 3.0 μm thickness and increase in the surface hardness from 225 HV for the untreated material up to about 2498 HV, for samples treated during 8 h. Creep tests were performed at 500°C and with loads varying from 25 to 40 MPa. Results indicated a decrease in the secondary creep rate for treated specimens when compared to the untreated ones. This behavior can be attributed to the formation of a nitride layer on the surface of Nb that acts as barrier to avoid the oxygen diffusion into the material under high temperature conditions.

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Evaluation of the resistance to oxidation of niobium treated by high temperature nitrogen Plasma Based Ion Implantation

Cited by 9 publications

References 14 publications

The Surface Treatment of Niobium Superconducting Reentrant Cavities by Means of High Temperature Nitrogen Plasma Based Ion Implantation

The Surface Treatment of Niobium Superconducting Reentrant Cavities by Means of High Temperature Nitrogen Plasma Based Ion Implantation

Interrelation Among Morphology, Mechanical Properties and Oxidation Behavior of NbxAlyNz Thin Films

The Influence of High‐Temperature Nitrogen Plasma‐Based Ion Implantation on Niobium Creep Behavior

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