Frictional characteristics of diamond like carbon and tungsten carbide/carbon coated high carbon high chromium steel against carbon in dry sliding conformal contact for mechanical seals

S Shankar,P Krishna Kumar

doi:10.1051/meca/2016036

Abstract

The present work investigates the friction characteristics of high carbon high chromium steel (HCHCr) stationary seal in contact with resin impregnated carbon rotating seal without any interfacial lubricant. An experimental setup was designed and fabricated to study the frictional characteristics of the seal for varying normal load and at a constant speed. The reliability and frictional performance had been improved further by providing DLC (diamond like carbon) and WC/C (tungsten carbide/carbon) coating over the substrate HCHCr D2 steel surface. Compared with the conventional stainless steel (316 SS) mechanical seals, uncoated HCHCr D2 steel had shown better frictional characteristics. Also further deposition of DLC and WC/C film on HCHCr D2 steel had shown significant improvement in the frictional torque, frictional coefficient and face temperature rise. The high hardness and low surface roughness of DLC and WC/C coated seal resulted in low and stable friction coefficient in the range of 0.04–0.05 without any measurable wear.

Highlights

In current practice, several different types of diamond like carbon (DLC) coatings [18], such as pure DLC, metal-doped DLC, and carbide-doped DLC, were utilized
The friction coefficient values of WC/C coated seal and DLC coated seal was found to be agreement with the previous works [27]. These results suggested that the WC/C coated seal exhibit higher wear resistance and lower frictional coefficient compared to DLC coated, high carbon high chromium steel (HCHCr) D2 steel and 316 SS seals
Frictional torque has the direct influence over the frictional coefficient

Summary

Introduction

Several different types of DLC coatings [18], such as pure DLC, metal-doped DLC, and carbide-doped DLC, were utilized. Tungsten carbide/carbon (WC/C) coating (a-C:H:W) [19] and pure DLC coating (a-C:H) were found to be more potential for sliding/rotating tribological surfaces. These coatings provide good wear resistance, low frictional coefficients, and high load bearing capacity. These coatings proved to be an efficient option in improving the tribological properties for various other mechanical components. Krishna Kumar: Mechanics & Industry 18, 115 (2017)

Methods

Results

Conclusion