Abstract
Academics and industry have sought after combining the exceptional properties of diamonds with the toughness of steel. Since the early 1990s several partial solutions have been found but chemical vapor deposition (CVD) diamond deposition on steel substrate continues to be a persistent problem. The main drawbacks are the high carbon diffusion from gas phase into substrate, the transition metals on the material surface that catalyze sp2 bond formation, instead of sp3 bonds, and the high thermal expansion coefficient (TEC) mismatch between diamond and steels. An intermediate layer has been found necessary to increase diamond adhesion. Literature has proposed many efficient intermediate layers as a diffusion barrier for both, carbon and iron, but most intermediate layers shown have not solved TEC mismatch. In this review, we briefly discuss the solutions that exclusively work as diffusion barrier and discuss in a broader way the ones that also solve, or may potentially solve, the TEC mismatch problem. We examine some multilayers, the iron borides, the chromium carbides, and vanadium carbides. We go through the most relevant results of the last two and a half decades, including recent advances in our group. Vanadium carbide looks promising since it has shown excellent diffusion barrier properties, its TEC is intermediary between diamond and steel and, it has been thickened to manage thermal stress relief. We also review a new deposition technique to set up intermediate layers: laser cladding. It is promising because of its versatility in mixing different materials and fusing and/or sintering them on a steel surface. We conclude by remarking on new perspectives.
Highlights
Low-pressure diamond synthesis by chemical vapor deposition (CVD) became economically important after more than 30 years of research and development [1,2]
It seemed that such intermediate layers combined with low-temperature deposition would be a successful way to apply diamond coatings on steel substrates, but besides the long-term research, there has been no perceptive growth on its practical use, which reveals that the problem remains partially solved
The stress developed at thewith interface high mismatch in thermal processed at dpi, mm/s and processed at dpi, mm/s and coefficients limits applicability, despite the high adherences remarked
Summary
Low-pressure diamond synthesis by chemical vapor deposition (CVD) became economically important after more than 30 years of research and development [1,2]. For the most studied intermediate layer, the CrN, we address the excellent and recent review of Chandran and Hoffman [25] At some point, it seemed that such intermediate layers combined with low-temperature deposition would be a successful way to apply diamond coatings on steel substrates, but besides the long-term research, there has been no perceptive growth on its practical use, which reveals that the problem remains partially solved. To mitigate such high stress in a single thin film is difficult Another frequent problem is that the intermediate layer may develop a phase with high TEC. Diamond coating on steel needs to be of good quality, adherent, and hand out low thermal residual stress For this reason we review mainly the alternatives to mitigate thermal stress
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
