Effect of ultrasonic vibration on tribological behavior of carbon-carbon composite

The current work aims to develop a biodegradable lubricant by adding different volume percentages of cashew nut shell liquid (CNSL) in neat castor oil (NCO) and investigating its possibility as rep...

Tribological analyses of a new optimized gearbox biodegradable lubricant blended with reduced graphene oxide nanoparticles

Lubrication reduces the friction between the interfaces of sliding surfaces in the mechanical seals that operate for extended period of time. Due to environmental issues caused by mineral oil-based lubricants, the use of organic based vegetable oils had increased worldwide due to the nontoxic and biodegradable characteristics. In this work an experimental study was carried out by employing a seal pair of tungsten carbide and resin impregnated carbon mechanical seals, its frictional behaviour was studied under the eco-friendly lubricant from the class of vegetable oils — soybean oil and canola oil with an eco-friendly solid lubricant i.e. boric acid powder. An experimental setup was designed and fabricated to study the frictional characteristics of the seal for varying normal load and constant speed. The friction characteristics was studied under unlubricated conditions, independent paraffin oil, soybean oil, canola oil lubricating modes and finally 1 wt.%, 3 wt.% and 5 wt.% of boric acid powder mixed individually with soybean and canola oil. After all running-in test of all lubricating conditions, 5 wt.% of boric acid powder mixed with soybean oil had contributed a hybrid tribofilm and resulted in the lowest friction coefficient value in the range of 0.06–0.07.

Experimental study on frictional characteristics of tungsten carbide versus carbon as mechanical seals under dry and eco-friendly lubrications

Frictional characteristics of impregnated graphite with different graphitization degree versus chromium stainless steel under varying PV values

Purpose




The purpose of this study was to investigate the frictional characteristics of the mechanical seals by using an efficient pairing by providing a suitable lubricant. Among all techniques and lubrication, deposition of solid lubricants on the sliding surface of the mechanical seal was found to be the most effective method to reduce frictional coefficient, frictional force and seal face temperature, thereby increasing the life time of mechanical seal.




Design/methodology/approach




In this study, two coatings, diamond-like carbon (DLC) and tungsten carbide/carbon (WC/C), was deposited over the stationary high-carbon high-chromium steel ring paired with resin-impregnated carbon. Their frictional characteristics were studied under various classes of liquid lubricants such as organic liquids, synthetic oil, mineral oil and vegetable oils using an experimental approach. Further, among all classes of liquid lubricants, the one which showed better frictional characteristics was mixed with 0.5, 1 and 2 wt% of potential environmental friendly solid lubricant – boric acid powder.




Findings




The high hardness and low surface roughness of DLC- and WC/C-coated seal with the lubricant of palm olein oil containing 1 wt% of boric acid powder contributed a hybrid tribofilm and resulted in low and stable friction coefficient in the range of 0.04-0.05 without any measurable wear.




Originality/value




A pair involving stationary DLC- and WC/C-coated seal ring and resin-impregnated carbon seal rotating ring for the application of mechanical seal was suggested and its frictional characteristics were studied under various classes of lubricants.

Frictional characteristics of PVD coated mechanical seals against carbon under various classes of liquid lubricants

This paper presents an investigative study on the frictional characteristics of alumina, 316 stainless steel, and phosphor bronze materials against resin-impregnated carbon in the form of mechanica...

Frictional study of alumina, 316 stainless steel, phosphor bronze versus carbon as mechanical seals under dry sliding conformal contact:

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.

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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

P. Krishna kumar

Papers

Experimental study on frictional characteristics of tungsten carbide versus carbon as mechanical seals under dry and eco-friendly lubrications

Frictional study of alumina, 316 stainless steel, phosphor bronze versus carbon as mechanical seals under dry sliding conformal contact:

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