hi, I think graphene is a good choice to improve the tribological behavior of a material. As u know graphene is an electrical conductor and it might positively influence electrical conductivity of the material as well.

I too feel grapheme is the closest answer.

Dear Babu A: 

A High Carbon and High Chromium is a steel proper to tool, commonly have been termed HCHCr-steel or Die-steel, a class of highly alloyed steel.

Sometimes, HCHCr-steel are considered erroneously as belonging to the stainless or semi-stainless class, but is not correct since its resistance to corrosion is very low due precipitation of chromium and carbon in carbides.

D-type group has high chromium content, in according to AISI, the hardness in maintained up to 425 oC. Typically, these steels undergoes a direct hardening at final production stage being air atmosphere hardened (D1and D2) or hardening via quenching in oil (D3) and can be hardened to 58-60 HRC. In a general way, consists until 2% of carbon and a maximum of 18% of Chromium, as well as Silicon and Manganese changing from 0.2 up to 0.35%. Also, it is possible some another compositions.

HCHCr – D Group has conventional composition added de 1% Mo, with from 10 to 18% of Cr, type D1 to D7 has been produced. Most common, sub-groups D2 and D3 has been commercialized.

HCHCr/D2 steel can be considered a hardened material. This steel is used for manufacturing press tools, dies: die-casting, and sheering blades, both basic application exhibits some limitation due the abrasion phenomenon. In this sense, further wear-resistance to support some kind of abrasive step during steel-tool use should be engineered.

HCHCr/D2 steel class can be annealed, forged, hardened and tempered. Some specific thermal cycles has been reported by manufacturers, see web-sites of manufacturers around the world. As an example, further hardening can be reached from slow heating up to 780 0C (minimum 730 oC), with subsequent treatment at specific soaking time, after heating up to 1300 0C (minimum 1000 oC), quenching can be carried out in ambient atmosphere or oil. Also, some degree of wear-resistance can be engineered during tempering or re-tempering at 200 oC or 400 oC. In this sense, proper temperature should be reached, holding (25 min)/(cm of thickness). As a whole, depending on the composition further thermal treatment should be tailored.

As above mentioned, further wear-resistance can be engineered by application of proper coating reaching to 150-200 micro-meters with enhanced hardness and sufficient electrical conductivity degree. Also, a multi-coating can be thought. From this point, the solution of problem is focused on the properties of the coating, starting from its hardness. Here, unfortunately, any scale of hardness applied to steel are functional since the coating hardness is further measured via Mohs scale of hardness.

However, a level of hardness from 8.5 up 10 of the Mohs Scale seems to exhibit a “degree of hardness” higher than most of maxima of another scale for steel. In this sense, carbon and any material derived of carbon are expected be non functional materials here, since intrinsic hardness of carbonaceous materials is low.

Some typical hard-materials for coating are WC, Al2O3.Cr (corindon), MgAl2O4.Cr, ZrO2.Cr and Diamond can be selected due high hardness being preferred materials with fine to ultra-fine granulometry. A priori, a classical coating is the cermet (ceramic-metal) with composition WC.10Co.4Cr. However, this kind of composition has been developed to medium carbon steel. As above mentioned, one of difficulties to coating deposition in a HCHCr can be the high amount of Carbides at surface, that might results in a kind of modulation of the wettability avoiding further physical interaction coating/surface, poor adhesion coating-surface. This feature can necessitate some composition modification to provide an adequate level of wettability of surface steel by coating. Also, perhaps a surface treatment can prepare the surface to coating deposition.

The materials listed above compose the major fraction of the coating. In this sense, classical wear based on the WC.Co.Cr coating can be stressed,. as an example: Corindon.Co.Cr, Diamond.Co.Cr and (MgAl2O4.Cr).Co.Cr.

Coating deposition can be reached by Thermal Spray Method. In specific, the method called High velocity Oxy-Fuel (HVOF). Due the fraction of Co and Cr metal, both thermal and electrical conductivity are expected be maintained.

I suggest a consult to the Prof. Dr. Herman Voorwald also a member of ReseacherGate about this type of coating under HCHCr steel and a possible interaction between Research groups. Also, it is possible view and pick pdf copies of several papers about this.

Kind regards.

Marcos Nobre (M. A. L. Nobre)

Thank you Marcos for the  detailed answer added . As you suggest i will consult with Prof. Dr. Herman Voorwald

Hi , I think you can use the atomic layer deposition method (ALD) as a unique method to improve the wear resistance, so Alumina films have high wear resistance  as demonstrated scientifically in conventional coatings methods but by ALD may be there isn't investigations as i think.  Thanks