Issues

Journal & Issues

Volume 22 (2022): Issue 3 (September 2022)

Volume 22 (2022): Issue 2 (June 2022)

Volume 22 (2022): Issue 1 (March 2022)

Volume 21 (2021): Issue 4 (December 2021)

Volume 21 (2021): Issue 3 (September 2021)

Volume 21 (2021): Issue 2 (June 2021)

Volume 21 (2021): Issue 1 (March 2021)

Volume 20 (2020): Issue 4 (December 2020)

Volume 20 (2020): Issue 3 (September 2020)

Volume 20 (2020): Issue 2 (June 2020)

Volume 20 (2020): Issue 1 (March 2020)

Volume 19 (2019): Issue 4 (December 2019)

Volume 19 (2019): Issue 3 (September 2019)

Volume 19 (2019): Issue 2 (June 2019)

Volume 19 (2019): Issue 1 (March 2019)

Volume 18 (2018): Issue 4 (December 2018)

Volume 18 (2018): Issue 3 (September 2018)

Volume 18 (2018): Issue 2 (June 2018)

Volume 18 (2018): Issue 1 (March 2018)

Volume 17 (2017): Issue 4 (December 2017)

Volume 17 (2017): Issue 3 (September 2017)

Volume 17 (2017): Issue 2 (June 2017)

Volume 17 (2017): Issue 1 (March 2017)

Volume 16 (2016): Issue 4 (December 2016)

Volume 16 (2016): Issue 3 (September 2016)

Volume 16 (2016): Issue 2 (June 2016)

Volume 16 (2016): Issue 1 (March 2016)

Volume 15 (2015): Issue 4 (December 2015)

Volume 15 (2015): Issue 3 (September 2015)

Volume 15 (2015): Issue 2 (June 2015)

Volume 15 (2015): Issue 1 (March 2015)

Volume 14 (2014): Issue 4 (December 2014)

Volume 14 (2014): Issue 3 (September 2014)

Volume 14 (2014): Issue 2 (June 2014)

Volume 14 (2014): Issue 1 (March 2014)

Volume 13 (2013): Issue 4 (December 2013)

Volume 13 (2013): Issue 3 (September 2013)

Volume 13 (2013): Issue 2 (June 2013)

Volume 13 (2013): Issue 1 (March 2013)

Volume 12 (2012): Issue 4 (December 2012)

Volume 12 (2012): Issue 3 (October 2012)

Volume 12 (2012): Issue 2 (June 2012)

Volume 12 (2012): Issue 1 (March 2012)

Volume 11 (2011): Issue 4 (December 2011)

Volume 11 (2011): Issue 3 (September 2011)

Volume 11 (2011): Issue 2 (June 2011)

Volume 11 (2011): Issue 1 (March 2011)

Volume 10 (2010): Issue 4 (December 2010)

Volume 10 (2010): Issue 3 (September 2010)

Volume 10 (2010): Issue 2 (June 2010)

Volume 10 (2010): Issue 1 (March 2010)

Volume 9 (2009): Issue 4 (December 2009)

Volume 9 (2009): Issue 3 (September 2009)

Volume 9 (2009): Issue 2 (June 2009)

Volume 9 (2009): Issue 1 (March 2009)

Volume 8 (2008): Issue 4 (December 2008)

Volume 8 (2008): Issue 3 (September 2008)

Volume 8 (2008): Issue 2 (June 2008)

Volume 8 (2008): Issue 1 (March 2008)

Journal Details
Format
Journal
eISSN
2083-4799
First Published
23 Sep 2008
Publication timeframe
4 times per year
Languages
English

Search

Volume 18 (2018): Issue 4 (December 2018)

Journal Details
Format
Journal
eISSN
2083-4799
First Published
23 Sep 2008
Publication timeframe
4 times per year
Languages
English

Search

5 Articles
Open Access

Storage of Hydrogen in Activated Carbons and Carbon Nanotubes

Published Online: 03 Jan 2019
Page range: 5 - 16

Abstract

Abstract

Activated carbons and carbon nanotube were synthesized with chemical and microwave processes of olive leaf in media with and without ultrasonic waves, and chemical vapor deposition method, respectively. The samples were characterized by x-ray diffraction, calorimetry, Brunauer, Emmett and Teller method, scanning electron microscopy/energy-dispersive X-ray, and zetasizer nano S90 instruments. The activated carbon synthesized in the ultrasonic bath had a higher surface area. The hydrogen adsorption capacity of carbon structures including activated carbons and carbon nanotube was measured as a function of pressure at 77 K. The hydrogen storage capacity of the carbon nanotube is 300% and 265% higher than the hydrogen storage capacity of activated carbons synthesized in medium without and with ultrasonic waves, respectively. Results showed the correlation between hydrogen storage capacity and specific surface area. The highest H2 storage value was obtained with carbon nanotube at 77 K. As a result, activated carbon and carbon nanotube can be used in hydrogen storage and therefore, the olive leaf can be converted into a high added value product in the energy field.

Keywords

  • Olive leaf
  • carbon nanotube
  • activated carbon
  • hydrogen energy
Open Access

Nanotubular Oxide Layers and Hydroxyapatite Coatings on Porous Titanium Alloy Ti13Nb13Zr

Published Online: 03 Jan 2019
Page range: 17 - 23

Abstract

Abstract

The surface condition of an implant has a significant impact on response occurring at the implant-biosystem border. The knowledge of physical-chemical and biological processes allows for targeted modification of biomaterials to induce a specified response of a tissue. The present research was aimed at development of technology composing of obtaining the nanotube oxide layers on a porous titanium alloy Ti13Nb13Zr, followed by the deposition of phosphate coating. The porous substrate (porosity about 50%) was prepared by a selective laser melting of the Ti13Nb13Zr powder with the SLM Realizer 100 equipment. The nanotubular oxide layers were fabricated by electrochemical oxidation in H3PO4 + 0.3% HF mixture for 30 min. at a constant voltage of 20V. The calcium phosphate coatings were formed by the electrochemically assisted deposition (ECAD). The presence of nanotubular oxide layers with their internal diameters ranging from 30 to 100 nm was observed by SEM (JEOL JSM-7600F). The nanotubes have dimensions that facilitated the deposition of hydroxyapatite.

Keywords

  • titanium alloy Ti13Nb13Zr
  • electrochemical oxidation
  • nanotubular titanium oxides
  • hydroxyapatite coatings
  • SEM
Open Access

Microstructure and Mechanical Properties of Ni-WC Thermal Sprayed Composite Coatings

Published Online: 03 Jan 2019
Page range: 24 - 34

Abstract

Abstact

The paper presents results of investigations of the microstructure and selected properties of improved composite coatings consisting mainly of nickel matrix reinforced by WC particles. The coatings were obtained by flame spraying of powders mixture on non-alloy steel substrates with following material remelting. Structural investigations were performed using both optical and electron microscopy. The distribution of microhardness and abrasion resistance of deposited coatings were also determined. The complex structure of coatings and resulting high wear withstand are the consequence of an intensive action of liquid matrix with dissolving tungsten carbide particles and formation of secondary phases.

Keywords

  • Composite coatings
  • thermal spraying process
  • Ni-WC
  • microstructure
Open Access

Influence of Dopants on Structure of Polycrystalline Bismuth Niobate

Published Online: 03 Jan 2019
Page range: 35 - 41

Abstract

Abstract

Bismuth niobate (BiNbO4) has attracted attention as a low-fired ceramics with promising microwave application potential. BiNbO4 ceramics was fabricated by mixed oxide method and sintered at temperature T<1000°C. As the sintering aids a small amount of CuO oxide was used. The crystalline structure of the ceramic samples was examined by X-ray diffraction method at room temperature. The Rietveld refinement method was used for analysis of diffraction data. As a result an influence of dopants on crystal structure of bismuth niobate (BiNbO4) ceramics was revealed. It was found that fabricated BiNbO4 ceramics adopted the orthorhombic symmetry (α-BiNbO4 phase, Pnna (52) space group). Small differences in elementary cell parameters were found.

Keywords

  • BiNbO ceramics
  • X-ray diffraction
  • phase analysis
  • crystal structure
Open Access

Investigation of Mechanical and Anti-Corrosion Properties of Flame Sprayed Coatings

Published Online: 03 Jan 2019
Page range: 42 - 53

Abstract

Abstract

This article presents the results of an examination of the properties of thermal flame sprayed coatings produced by material in the form of four powders (two polymers: PA11 and PA12 CastoPlast, and two high purity: tin and aluminum) on the substrate of the unalloyed structural steel of S235JR grade. Investigations of coating properties are based on metallography tests (SEM and CLSM), measurement of microhardness (acc. to PN-EN ISO 6507-1:2007), anticorrosive (acc. to PN-EN ISO 9227:2017-06) and bend testing. Results demonstrate properties of flame sprayed coatings that are especially promising in the industrial applications where corrosion-resistant coating properties are required. Consequently, performed experiments show that the highest corrosion resistance is demonstrated by steel samples with a polyamide anti-corrosion system. Accelerated corrosion tests showed the lowest corrosion resistance of the tin coating system, however, they do not fully correspond to the corrosion processes in operating conditions.

Keywords

  • Flame spray technology
  • polymer powder
  • aluminum powder
  • tin powder
  • corrosion-resistant coating
5 Articles
Open Access

Storage of Hydrogen in Activated Carbons and Carbon Nanotubes

Published Online: 03 Jan 2019
Page range: 5 - 16

Abstract

Abstract

Activated carbons and carbon nanotube were synthesized with chemical and microwave processes of olive leaf in media with and without ultrasonic waves, and chemical vapor deposition method, respectively. The samples were characterized by x-ray diffraction, calorimetry, Brunauer, Emmett and Teller method, scanning electron microscopy/energy-dispersive X-ray, and zetasizer nano S90 instruments. The activated carbon synthesized in the ultrasonic bath had a higher surface area. The hydrogen adsorption capacity of carbon structures including activated carbons and carbon nanotube was measured as a function of pressure at 77 K. The hydrogen storage capacity of the carbon nanotube is 300% and 265% higher than the hydrogen storage capacity of activated carbons synthesized in medium without and with ultrasonic waves, respectively. Results showed the correlation between hydrogen storage capacity and specific surface area. The highest H2 storage value was obtained with carbon nanotube at 77 K. As a result, activated carbon and carbon nanotube can be used in hydrogen storage and therefore, the olive leaf can be converted into a high added value product in the energy field.

Keywords

  • Olive leaf
  • carbon nanotube
  • activated carbon
  • hydrogen energy
Open Access

Nanotubular Oxide Layers and Hydroxyapatite Coatings on Porous Titanium Alloy Ti13Nb13Zr

Published Online: 03 Jan 2019
Page range: 17 - 23

Abstract

Abstract

The surface condition of an implant has a significant impact on response occurring at the implant-biosystem border. The knowledge of physical-chemical and biological processes allows for targeted modification of biomaterials to induce a specified response of a tissue. The present research was aimed at development of technology composing of obtaining the nanotube oxide layers on a porous titanium alloy Ti13Nb13Zr, followed by the deposition of phosphate coating. The porous substrate (porosity about 50%) was prepared by a selective laser melting of the Ti13Nb13Zr powder with the SLM Realizer 100 equipment. The nanotubular oxide layers were fabricated by electrochemical oxidation in H3PO4 + 0.3% HF mixture for 30 min. at a constant voltage of 20V. The calcium phosphate coatings were formed by the electrochemically assisted deposition (ECAD). The presence of nanotubular oxide layers with their internal diameters ranging from 30 to 100 nm was observed by SEM (JEOL JSM-7600F). The nanotubes have dimensions that facilitated the deposition of hydroxyapatite.

Keywords

  • titanium alloy Ti13Nb13Zr
  • electrochemical oxidation
  • nanotubular titanium oxides
  • hydroxyapatite coatings
  • SEM
Open Access

Microstructure and Mechanical Properties of Ni-WC Thermal Sprayed Composite Coatings

Published Online: 03 Jan 2019
Page range: 24 - 34

Abstract

Abstact

The paper presents results of investigations of the microstructure and selected properties of improved composite coatings consisting mainly of nickel matrix reinforced by WC particles. The coatings were obtained by flame spraying of powders mixture on non-alloy steel substrates with following material remelting. Structural investigations were performed using both optical and electron microscopy. The distribution of microhardness and abrasion resistance of deposited coatings were also determined. The complex structure of coatings and resulting high wear withstand are the consequence of an intensive action of liquid matrix with dissolving tungsten carbide particles and formation of secondary phases.

Keywords

  • Composite coatings
  • thermal spraying process
  • Ni-WC
  • microstructure
Open Access

Influence of Dopants on Structure of Polycrystalline Bismuth Niobate

Published Online: 03 Jan 2019
Page range: 35 - 41

Abstract

Abstract

Bismuth niobate (BiNbO4) has attracted attention as a low-fired ceramics with promising microwave application potential. BiNbO4 ceramics was fabricated by mixed oxide method and sintered at temperature T<1000°C. As the sintering aids a small amount of CuO oxide was used. The crystalline structure of the ceramic samples was examined by X-ray diffraction method at room temperature. The Rietveld refinement method was used for analysis of diffraction data. As a result an influence of dopants on crystal structure of bismuth niobate (BiNbO4) ceramics was revealed. It was found that fabricated BiNbO4 ceramics adopted the orthorhombic symmetry (α-BiNbO4 phase, Pnna (52) space group). Small differences in elementary cell parameters were found.

Keywords

  • BiNbO ceramics
  • X-ray diffraction
  • phase analysis
  • crystal structure
Open Access

Investigation of Mechanical and Anti-Corrosion Properties of Flame Sprayed Coatings

Published Online: 03 Jan 2019
Page range: 42 - 53

Abstract

Abstract

This article presents the results of an examination of the properties of thermal flame sprayed coatings produced by material in the form of four powders (two polymers: PA11 and PA12 CastoPlast, and two high purity: tin and aluminum) on the substrate of the unalloyed structural steel of S235JR grade. Investigations of coating properties are based on metallography tests (SEM and CLSM), measurement of microhardness (acc. to PN-EN ISO 6507-1:2007), anticorrosive (acc. to PN-EN ISO 9227:2017-06) and bend testing. Results demonstrate properties of flame sprayed coatings that are especially promising in the industrial applications where corrosion-resistant coating properties are required. Consequently, performed experiments show that the highest corrosion resistance is demonstrated by steel samples with a polyamide anti-corrosion system. Accelerated corrosion tests showed the lowest corrosion resistance of the tin coating system, however, they do not fully correspond to the corrosion processes in operating conditions.

Keywords

  • Flame spray technology
  • polymer powder
  • aluminum powder
  • tin powder
  • corrosion-resistant coating

Plan your remote conference with Sciendo