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Laser cladding: A high-speed-imaging examination of powder catchment efficiency as a function of the melt pool geometry and its position under the powder stream (2023)
Journal Article
Koti, D., Powell, J., Naesstroem, H., Spaccapaniccia, C., & Voisey, K. T. (2023). Laser cladding: A high-speed-imaging examination of powder catchment efficiency as a function of the melt pool geometry and its position under the powder stream. Journal of Laser Applications, 35(4), Article 042065. https://doi.org/10.2351/7.0001199

This paper provides quantitative information about the paths taken by blown powder particles during laser cladding. A proportion of the powder is "wasted" by bouncing off the solid areas surrounding the melt pool. This wastage reduces the productivit... Read More about Laser cladding: A high-speed-imaging examination of powder catchment efficiency as a function of the melt pool geometry and its position under the powder stream.

Lifetime of MoS2 based DFL systems in fretting with and without a Cu-Ni-In under-layer: the dependence on the topography of the surface onto which the DFL is deposited (2023)
Journal Article
Laolu-Balogun, E., Owen, S., Booth, T., Pattinson, G., Shipway, P., & Voisey, K. (2023). Lifetime of MoS2 based DFL systems in fretting with and without a Cu-Ni-In under-layer: the dependence on the topography of the surface onto which the DFL is deposited. Tribology International, 188, Article 108863. https://doi.org/10.1016/j.triboint.2023.108863

The superior fretting performance of polymer-bonded MoS2-based dry film lubricant (DFL) coating on a plasma-sprayed Cu-Ni-In under-layer is well known. The Cu-Ni-In under-layer changes both the material and the topography of the sur... Read More about Lifetime of MoS2 based DFL systems in fretting with and without a Cu-Ni-In under-layer: the dependence on the topography of the surface onto which the DFL is deposited.

Powder catchment efficiency in laser cladding (directed energy deposition). An investigation into standard laser cladding and the ABA cladding technique (2023)
Journal Article
Koti, D., Powell, J., Naesstroem, H., & Voisey, K. T. (2023). Powder catchment efficiency in laser cladding (directed energy deposition). An investigation into standard laser cladding and the ABA cladding technique. Journal of Laser Applications, 35, Article 012025. https://doi.org/10.2351/7.0000904

This paper investigates the efficiency of powder catchment in blown powder laser cladding (a directed energy deposition technique). A comparison is made between standard “track by overlapping track” cladding (“AAA” cladding) and “ABA” cladding, where... Read More about Powder catchment efficiency in laser cladding (directed energy deposition). An investigation into standard laser cladding and the ABA cladding technique.

Assessing the quality and productivity of laser cladding and direct energy deposition: Guidelines for researchers (2023)
Journal Article
Powell, J., Koti, D., Garmendia, X., & Voisey, K. T. (2023). Assessing the quality and productivity of laser cladding and direct energy deposition: Guidelines for researchers. Journal of Laser Applications, 35(1), Article 012024. https://doi.org/10.2351/7.0000897

This paper provides guidelines and advice to researchers and engineers in the field of laser cladding and related direct energy deposition techniques to help establish a standardized approach to quality assessment and productivity metrics. Factors co... Read More about Assessing the quality and productivity of laser cladding and direct energy deposition: Guidelines for researchers.

Improving laser cladding productivity with ‘ABA’ cladding (2022)
Journal Article
Koti, D., Powell, J., & Voisey, K. (2022). Improving laser cladding productivity with ‘ABA’ cladding. Procedia CIRP, 111, 205-209. https://doi.org/10.1016/j.procir.2022.08.048

Laser Cladding is one of several processes within Additive Manufacturing and usually involves the production of a clad surface by adding parallel, overlapping lines of clad material to the surface of a substrate. In this work a new laser cladding tec... Read More about Improving laser cladding productivity with ‘ABA’ cladding.

Laser drilling of micro-holes in single crystal silicon, indium phosphide and indium antimonide using a continuous wave (CW) 1070 nm fibre laser with millisecond pulse widths (2018)
Journal Article
Maclean, J. O., Tangkijcharoenchai, C., Coomber, S., & Voisey, K. T. (2018). Laser drilling of micro-holes in single crystal silicon, indium phosphide and indium antimonide using a continuous wave (CW) 1070 nm fibre laser with millisecond pulse widths. Procedia CIRP, 74, 407-412. https://doi.org/10.1016/j.procir.2018.08.158

The laser micro-drilling of “thru” holes, also known as via holes, in Si, InP and InSb semiconductor wafers was studied using millisecond pulse lengths from an IPG Laser Model YLR-2000 CW multimode 2 kW Ytterbium Fibre Laser and a JK400 (400 W) fibre... Read More about Laser drilling of micro-holes in single crystal silicon, indium phosphide and indium antimonide using a continuous wave (CW) 1070 nm fibre laser with millisecond pulse widths.

Fibre laser cutting: the use of carbon-filled acrylic as a qualitative and quantitative analysis tool (2018)
Journal Article
Atiyah, H., Powell, J., Petring, D., Stoyanov, S., & Voisey, K. (2018). Fibre laser cutting: the use of carbon-filled acrylic as a qualitative and quantitative analysis tool. Journal of Laser Applications, 30(3), Article 032009. https://doi.org/10.2351/1.5045349

The use of carbon filled black acrylic (CFBA) as a quantitative and qualitative analytical tool for fibre laser cutting is investigated. In the qualitative work CFBA targets placed below the laser cutting zone when cutting stainless steel showed a d... Read More about Fibre laser cutting: the use of carbon-filled acrylic as a qualitative and quantitative analysis tool.

The role of a thermally sprayed CuNiIn underlayer in the durability of a dry-film lubricant system in fretting: a phenomenological model (2018)
Journal Article
Barman, K., Shipway, P., Voisey, K., & Pattinson, G. (2018). The role of a thermally sprayed CuNiIn underlayer in the durability of a dry-film lubricant system in fretting: a phenomenological model. Tribology International, 123, https://doi.org/10.1016/j.triboint.2018.03.018

Dry film lubricant coatings (DFL) are employed to reduce friction and damage in highly loaded contacts. Metallic underlayers, e.g. CuNiIn, can be beneficial however, there is no detailed explanation of the mechanism. This work investigates the effect... Read More about The role of a thermally sprayed CuNiIn underlayer in the durability of a dry-film lubricant system in fretting: a phenomenological model.

An investigation into whether the laser drilling capabilities of a 2kW fibre laser can be enhanced using pulse train shaping (2018)
Journal Article
Markcoons, D., & Voisey, K. (2018). An investigation into whether the laser drilling capabilities of a 2kW fibre laser can be enhanced using pulse train shaping. Lasers in Engineering, 39(1-2),

In long, ms, pulsed melt ejected based laser drilling of metals pulse train shaping has previously improved drilling efficiency. This work investigates if pulse train shaping can be exploited in the laser drilling of 0.8-2 mm mild steel with a 1070 n... Read More about An investigation into whether the laser drilling capabilities of a 2kW fibre laser can be enhanced using pulse train shaping.

The effect of coating architecture and defects on the corrosion behaviour of a PVD multilayer Inconel 625/Cr coating (2017)
Journal Article
Daure, J., Voisey, K., Shipway, P., & Stewart, D. (2017). The effect of coating architecture and defects on the corrosion behaviour of a PVD multilayer Inconel 625/Cr coating. Surface and Coatings Technology, 324, https://doi.org/10.1016/j.surfcoat.2017.06.009

This paper investigates the effect of substrate surface finish and deposition conditions of PVD multilayer Inconel 625/Cr coatings on their ability to act as a corrosion-barrier. The corrosion-barrier performance of the coatings was characterized by... Read More about The effect of coating architecture and defects on the corrosion behaviour of a PVD multilayer Inconel 625/Cr coating.

Application of ray-tracing to interpreting beam prints from fibre laser cutting (2017)
Journal Article
Alotaibi, M., Atiyah, H., MacKenzie, R., & Voisey, K. (2017). Application of ray-tracing to interpreting beam prints from fibre laser cutting. Lasers in Engineering, 39(1-2),

2D ray-tracing has been used to investigate the influence of inclined cutting front and the cutting edge on the exiting, surplus, laser beam while cutting 6 mm mild steel with a fibre laser, wavelength = 1070 nm. The ray-tracing model, which assumed... Read More about Application of ray-tracing to interpreting beam prints from fibre laser cutting.

Role of oxides and porosity on high temperature oxidation of liquid fuelled HVOF thermal sprayed Ni50Cr coatings (2017)
Journal Article
Song, B., Bai, M., Voisey, K. T., & Hussain, T. (2017). Role of oxides and porosity on high temperature oxidation of liquid fuelled HVOF thermal sprayed Ni50Cr coatings. Journal of Thermal Spray Technology, 26(3), 554-568. https://doi.org/10.1007/s11666-017-0531-z

High chromium content in Ni50Cr thermally sprayed coatings can generate a dense and protective scale at the surface of coating. Thus, the Ni50Cr coating is widely used in high temperature oxidation and corrosion applications. A commercially available... Read More about Role of oxides and porosity on high temperature oxidation of liquid fuelled HVOF thermal sprayed Ni50Cr coatings.

Evolution of damage in MoS2-based dry film lubricants (DFLs) in fretting wear – the effect of DFL thickness and contact geometry (2017)
Journal Article
Barman, K., Shipway, P., Voisey, K., & Pattinson, G. (2017). Evolution of damage in MoS2-based dry film lubricants (DFLs) in fretting wear – the effect of DFL thickness and contact geometry. Progress in Organic Coatings, 105, https://doi.org/10.1016/j.porgcoat.2016.12.022

Dry film lubricant (DFL) coatings are widely used to reduce coefficients of friction and damage in highly loaded contacts. This work investigates the behaviour of a commercially available MoS2-based DFL in a cylinder-on-flat contact geometry with a f... Read More about Evolution of damage in MoS2-based dry film lubricants (DFLs) in fretting wear – the effect of DFL thickness and contact geometry.

Incorporation and evolution of ZrO2 nano-particles in Pt-modified aluminide coating for high temperature applications (2016)
Journal Article
Qian, L., Xu, F., Voisey, K., Nekouie, V., Zhou, Z., Silberschmidt, V. V., & Hou, X. (2017). Incorporation and evolution of ZrO2 nano-particles in Pt-modified aluminide coating for high temperature applications. Surface and Coatings Technology, 311, https://doi.org/10.1016/j.surfcoat.2016.12.106

ZrO2 nano-particles were incorporated into electro-deposited PtAl coatings in an attempt to enhance their performance by exploiting the effect of reactive element oxides. PtAl coatings with and without ZrO2 particles were deposited onto three commerc... Read More about Incorporation and evolution of ZrO2 nano-particles in Pt-modified aluminide coating for high temperature applications.

Gas and liquid-fuelled HVOF spraying of Ni50Cr coating: microstructure and high temperature oxidation (2016)
Journal Article
Song, B., Pala, Z., Voisey, K., & Hussain, T. (in press). Gas and liquid-fuelled HVOF spraying of Ni50Cr coating: microstructure and high temperature oxidation. Surface and Coatings Technology, https://doi.org/10.1016/j.surfcoat.2016.07.046

Ni50Cr thermally sprayed coatings are widely used for high temperature oxidation and corrosion in thermal power plants. In this study, a commercially available gas atomised Ni50Cr powder was sprayed onto a power plant alloy (ASME P92) using both gas... Read More about Gas and liquid-fuelled HVOF spraying of Ni50Cr coating: microstructure and high temperature oxidation.

Modelling and experimental study on ?-phase depletion behaviour of HVOF sprayed free-standing CoNiCrAlY coatings during oxidation (2016)
Journal Article
Chen, H., Jackson, G., Voisey, K., & McCartney, D. (2016). Modelling and experimental study on ?-phase depletion behaviour of HVOF sprayed free-standing CoNiCrAlY coatings during oxidation. Surface and Coatings Technology, 291, 34-42. https://doi.org/10.1016/j.surfcoat.2016.02.008

This paper investigates the β-phase depletion behaviour during oxidation of free-standing CoNiCrA1Y (Co-31.7%Ni-20.8%Cr-8.1%A1-0.5%Y, all in wt%) bond coats prepared by high velocity oxy-fuel (HVOF) thermal spraying. The microstructure of the coating... Read More about Modelling and experimental study on ?-phase depletion behaviour of HVOF sprayed free-standing CoNiCrAlY coatings during oxidation.

Laser drilling of via micro-holes in single-crystal semiconductor substrates using a 1070nm fibre laser with millisecond pulse widths (2015)
Journal Article
Maclean, J. O., Hodson, J. R., & Voisey, K. T. (2015). Laser drilling of via micro-holes in single-crystal semiconductor substrates using a 1070nm fibre laser with millisecond pulse widths. Proceedings of SPIE, 9657, Article 965704. https://doi.org/10.1117/12.2175898

© 2015 SPIE. Micro-machining of semiconductors is relevant to fabrication challenges within the semiconductor industry. For via holes for solar cells, laser drilling potentially avoids deep plasma etching which requires sophisticated equipment and co... Read More about Laser drilling of via micro-holes in single-crystal semiconductor substrates using a 1070nm fibre laser with millisecond pulse widths.

Effect of surface conditions on internal oxidation and nitridation of HVOF MCrAlY coatings (2015)
Journal Article
Chen, H., McCartney, D., & Voisey, K. (in press). Effect of surface conditions on internal oxidation and nitridation of HVOF MCrAlY coatings. Materials at High Temperatures, 32(1-2), https://doi.org/10.1179/0960340914Z.000000000103

This study deals with the isothermal oxidation behaviour of high velocity oxy-fuel sprayed MCrAlY coatings. Both free-standing coatings and coatings attached to IN738 and CMSX4 substrates undergo isothermal oxidation at 1100°C for up to 100h. The eff... Read More about Effect of surface conditions on internal oxidation and nitridation of HVOF MCrAlY coatings.

The application of specific point energy analysis to laser cutting with 1 ?m laser radiation (2014)
Journal Article
Hashemzadeh, M., Suder, W., Williams, S., Powell, J., Kaplan, A., & Voisey, K. (2014). The application of specific point energy analysis to laser cutting with 1 ?m laser radiation. Physics Procedia, 56, https://doi.org/10.1016/j.phpro.2014.08.110

Specific point energy (SPE) is a concept that has been successfully used in laser welding where SPE and power density determine penetration depth. This type of analysis allows the welding characteristics of different laser systems to be directly comp... Read More about The application of specific point energy analysis to laser cutting with 1 ?m laser radiation.

Fibre laser piercing of mild steel: the effects of power intensity, gas type and pressure (2014)
Journal Article
Hashemzadeh, M., Powell, J., & Voisey, K. (2014). Fibre laser piercing of mild steel: the effects of power intensity, gas type and pressure. Optics and Lasers in Engineering, 55, https://doi.org/10.1016/j.optlaseng.2013.10.001

Laser piercing is used to generate a starting point for laser cutting. The pierced hole is normally larger than the kerf width, which means that it cannot lie on the cut line. An experimental program investigating the piercing process as a function o... Read More about Fibre laser piercing of mild steel: the effects of power intensity, gas type and pressure.