<abstract xmlns="http://www.w3.org/1999/xhtml">

The purpose of this work was to carry out comparative studies of WC-Co-Cr coatings deposited using the high velocity oxy fuel (HVOF) method onto two types of substrate material: structural steel S235 and magnesium alloy AZ31. The influence of the substrate material type on the microstructure, phase composition, crystallite size, porosity, Vickers microhardness, instrumental hardness (HIT), Young’s modulus (EIT), and fracture toughness was investigated. For both substrates, the deposited coatings deposited were characterized with fine-grained and compact microstructure. The X-ray diffraction (XRD) revealed presence of following phases: WC, W2C, Co0.9W0.1, and Co3W9C4. The WC phase was the most desirable and stable one with crystallites were below 100 nm. On the other hand, the size of the W2C crystallites was below 30 nm. The coatings obtained showed porosity values equal to 2.3 ± 0.4 vol% and 2.8 ± 0.7 vol% for AZ31 and S235, respectively. The average Vickers microhardness for both types of sample was appproximately 1200 HV0.3. The average HIT values for carbide particles and metallic matrix were around 29 GPa and 6.5 GPa, respectively. In the case of EIT, it was around 620 GPa and 190 GPa for WC and Co-Cr, respectively. The differences between coatings were negligible. The EIT value for both coatings was equal to 344 ± 11 GPa. The fracture toughness was around 4.5 MPa · m1/2 in both cases. The investigations revealed that it is possible to replace steel substrate material with a much lighter equivalent, in this case AZ31 alloy, without deterioration of the coating properties.
</abstract>

The purpose of this work was to carry out comparative studies of WC-Co-Cr coatings deposited using the high velocity oxy fuel (HVOF) method onto two types of substrate material: structural steel S235 and magnesium alloy AZ31. The influence of the substrate material type on the microstructure, phase composition, crystallite size, porosity, Vickers microhardness, instrumental hardness (HIT), Young’s modulus (EIT), and fracture toughness was investigated. For both substrates, the deposited coatings deposited were characterized with fine-grained and compact microstructure. The X-ray diffraction (XRD) revealed presence of following phases: WC, W2C, Co0.9W0.1, and Co3W9C4. The WC phase was the most desirable and stable one with crystallites were below 100 nm. On the other hand, the size of the W2C crystallites was below 30 nm. The coatings obtained showed porosity values equal to 2.3 ± 0.4 vol% and 2.8 ± 0.7 vol% for AZ31 and S235, respectively. The average Vickers microhardness for both types of sample was appproximately 1200 HV0.3. The average HIT values for carbide particles and metallic matrix were around 29 GPa and 6.5 GPa, respectively. In the case of EIT, it was around 620 GPa and 190 GPa for WC and Co-Cr, respectively. The differences between coatings were negligible. The EIT value for both coatings was equal to 344 ± 11 GPa. The fracture toughness was around 4.5 MPa · m1/2 in both cases. The investigations revealed that it is possible to replace steel substrate material with a much lighter equivalent, in this case AZ31 alloy, without deterioration of the coating properties.

Comparative analysis of microstructure and selected properties of WC-Co-Cr coatings sprayed by high-velocity oxy fuel on S235 and AZ31 substrates

Materials Science-Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

The purpose of this work was to carry out comparative studies of WC-Co-Cr coatings deposited using the high velocity oxy fuel (HVOF) method onto two types of...

Sample	Medium feed rate				Spray distance mm
Sample	Kerosene l/min	Oxygen l/min	Nitrogen l/min	Powder g/min	Spray distance mm
SBS¹	0.380	950	12	70	300
MBS²	0.435	900			360

Sample	Ra	Rp	Rv	Rz
SBS	3.36 ± 0.23	10.20 ± 2.14	7.95 ± 1.48	18.10 ± 3.15
MBS	4.28 ± 0.24	11.84 ± 2.47	9.92 ± 1.83	21.77 ± 3.51

Sample	CRI value
SBS	0.915
MBS	0.928

Sample	H_IT (WC) GPa	E_IT (WC) GPa	H_IT (Co-Cr) GPa	E_IT (Co-Cr) GPa
SBS	29.14 ± 1.91	622 ± 17	6.52 ± 0.47	192 ± 9
MBS	28.65 ± 1.94	624 ± 18	6.46 ± 0.42	193 ± 8

Comparative analysis of microstructure and selected properties of WC-Co-Cr coatings sprayed by high-velocity oxy fuel on S235 and AZ31 substrates

Published Online: May 08, 2024

Page range: 32 - 41

Received: Feb 13, 2024

Accepted: Mar 17, 2024

DOI: https://doi.org/10.2478/msp-2024-0002

Keywords
structural steel, magnesium alloy, cermet coatings, HVOF, mechanical properties, microstructure, phase analysis

© 2024 Ewa Jonda et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

Fig. 7.

HVOF process parameters and sample code

Results for surface roughness of the as-sprayed coatings

Results for CRI calculations

The IIT results for carbide particles and metallic matrix in sprayed coatings

Comparative analysis of microstructure and selected properties of WC-Co-Cr coatings sprayed by high-velocity oxy fuel on S235 and AZ31 substrates

Published Online: May 08, 2024

Page range: 32 - 41

Received: Feb 13, 2024

Accepted: Mar 17, 2024

DOI: https://doi.org/10.2478/msp-2024-0002

Keywordsstructural steel, magnesium alloy, cermet coatings, HVOF, mechanical properties, microstructure, phase analysis

© 2024 Ewa Jonda et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

Fig. 7.

HVOF process parameters and sample code

Results for surface roughness of the as-sprayed coatings

Results for CRI calculations

The IIT results for carbide particles and metallic matrix in sprayed coatings

Keywords
structural steel, magnesium alloy, cermet coatings, HVOF, mechanical properties, microstructure, phase analysis