A Novel Method to Deposit Vanadium Carbide Interlayer on Tool Steel Substrate Applied to Mitigate CVD Diamond Thermal Stresses

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 55; no. 9; pp. 3478 - 3491
• Main Authors: Damm, D. D., Volu, R. M., Correia, R. F. B. O., Almeida, K. F., Trava-Airoldi, V. J., de Vasconcelos, G., Barquete, D. M., Corat, E. J.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2024; Springer Nature B.V
• Subjects: Carbide tools; Characterization and Evaluation of Materials; Chemical vapor deposition; Chemistry and Materials Science; Compressive properties; Diamond films; Diamond tools; Diffusion barriers; Diffusion coating; Diffusion layers; Electrons; Field emission; Interlayers; Laser beam cladding; Materials Science; Metallic Materials; Nanotechnology; Original Research Article; Phase transitions; Raman spectroscopy; Rapid solidification; Residual stress; Salt baths; Spectrum analysis; Structural Materials; Substrates; Surfaces and Interfaces; Thermal expansion; Thermal stress; Thin Films; Tool steels; Vanadium carbide
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-024-07491-9

This work shows considerable advance in combining the exceptional properties of chemical vapor deposition (CVD) diamond with the toughness of steel, a subject that has been sought since the early 1990s. Combining both the previously developed techniques for vanadium carbide (VC) deposition, namely laser cladding vanadium carbide (LCVC) and thermo-reactive deposition (TRD) in a salt bath, made it possible to achieve the deposition of a CVD diamond film on a D6 tool steel, with a very low stress level of 1.8 ± 0.1 GPa. This was the lowest value for growth at 750 °C substrate temperature. The LCVC step was a fast processing to thicken the VC layer, while the short-term TRD (only 1 hour) closed the cracks left in the LCVC coating, relieved the residual stresses resulting from the rapid solidification after the laser incidence, and promoted a phase transformation from V 8 C 7 to V 6 C 5 , a phase with lower thermal expansion coefficient. Hot Filament Chemical Vapor Deposition (HFCVD) was used to perform the CVD diamond deposition. The vanadium carbide layer has been an intermediate layer capable of acting as an excellent diffusion barrier and able to satisfactorily mitigate the thermal stress of the CVD diamond. The samples were characterized by Scanning Electron Microscopy with Field Emission Gun (FEG-SEM) equipped with Energy-Dispersive X-ray Spectroscopy (EDS), X-ray diffractometry, Rockwell A (588.6 N) indentation tester. Raman spectroscopy was used to further characterize HFCVD diamond, to compute the thermal compressive stress.