Journal Published Online: 20 October 2023
Volume 12, Issue 3

Niobium Boronizing: Influence of the Treatment Temperature and Time



The application of niobium borides to components such as lamination cylinders, hightemperature devices, and medical equipment shows their importance and versatility in engineering. To improve niobium’s mechanical resistance and possible oxidation resistance at temperature, this research applied boronizing to pure niobium, carried out with double pack cementation. Boronizing at 950°C and 1,100°C was carried out for 1 and 4 h. Ekabor commercial pack mixture with a nominal chemical composition of 90 % silicon carbide, 5 % boron carbide, and 5 % potassium tetrafluoroborate was used with and without 10 percent by weight (wt%) silicon addition. Scanning electron microscope, energy dispersive spectroscopy, and X-ray diffraction analyses and microhardness tests were used to characterize the treated samples. A continuous high-hardness 2,394-HV0.1 (23.5 GPa) niobium diboride layer was formed at the surface of the niobium substrate. A maximum layer thickness of 53.6 ± 2.9 µm was measured after 4 h at 1,100°C, whereas after 1 h at 950°C, no visible layer was identified with the applied characterization techniques, suggesting a threshold in this temperature. Adding 10 wt% silicon to the pack mixture impacted the kinetics of the diffusion process, which resulted in an increase in layer thickness of 72.6 ± 10.1 µm after processing for 1 h at 1,100°C, but cracks formed in the processed surface.

Author Information

Ferreira, Lauro Mariano
Post Graduation Program in Materials Science and Engineering, Federal University of Paraná, Curitiba, Paraná, Brazil
Cardoso, Rodrigo Perito
Mechanical Engineering Department, Federal University of Santa Catarina, Centro de Tecnologia Rua Engenheiro Agronômico Andrei Cristian Ferreira, s/n - Trindade, Florianópolis, Santa Catarina, Brazil
D’Oliveira, Ana Sofia C. M.
Mechanical Engineering Department, Federal University of Paraná, Curitiba, Paraná, Brazil
Pages: 10
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Stock #: MPC20220122
ISSN: 2379-1365
DOI: 10.1520/MPC20220122