RESEARCH OF WEAR RESISTANCE OF CHROME DIAMOND COATING
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2020-01-01 |
| Journal | Metal … |
| Authors | Julia Averina, Galina Kalyakina, В. С. Болдырев, А. Г. Чередниченко, Evgenia Rybina |
| Institutions | Peoples’ Friendship University of Russia, D. Mendeleyev University of Chemical Technology of Russia |
| Citations | 1 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”This research details the development and characterization of a nanodiamond (ND) chrome composite coating designed to significantly enhance the performance characteristics of conventional hard chrome plating.
- Core Value Proposition: The ND chrome coating improves physicomechanical indices, wear resistance, and corrosion resistance, potentially extending the service life of tools and friction parts by 2-15 times compared to standard hard chromium plating.
- Corrosion Resistance: The coating demonstrated exceptional non-porosity, confirmed by the filter paper method, even at minimum tested thicknesses (11.852 µm), preventing corrosive media from reaching the steel substrate.
- Mechanical Hardness: Microhardness testing yielded values up to 328.4 MPa (HV0.2). The authors note that based on literature, this technology has the potential to achieve hardness levels up to 1000 MPa.
- Wear Performance: Taber abrasimeter testing showed consistent wear resistance across all tested thicknesses, with weight loss ranging from 30 mg to 40 mg after 5000 cycles (500 g load, 60 rpm).
- Aesthetic Quality: The coating exhibits good gloss, ranging from 62 to 74 Gloss Units (GU) at a 20° angle, making it suitable for applications requiring both protection and a shiny finish.
- Conclusion: The ND chrome coating, even at thicknesses as low as 10 µm, is non-porous, possesses good hardness and wear resistance, and is comparable to shiny chrome in gloss, positioning it as a superior replacement for certain types of chromium plating.
Technical Specifications
Section titled “Technical Specifications”The following data summarizes the measured physical and mechanical properties of the nanodiamond chrome coatings (Samples 1, 2, and 3).
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Coating Thickness (Sample 1) | 11.852 | µm | Measured via OLYMPUS LEXT OLS4100 |
| Coating Thickness (Sample 3) | 46.340 | µm | Maximum thickness tested |
| Microhardness (Sample 1) | 328.4 | MPa | Vickers method (HV0.2 load) |
| Microhardness (Sample 2) | 318.9 | MPa | Vickers method (HV0.2 load) |
| Theoretical Max Hardness | 1000 | MPa | Potential hard chromium plating value (Ref. [4]) |
| Wear Test Load | 500 | g | Taber rotational abrasimeter |
| Wear Test Speed | 60 | rpm | Taber rotational abrasimeter |
| Wear Test Cycles | 5000 | cycles | Standard test duration |
| Minimum Wear Loss (Sample 2) | 30 | mg | Weight loss after 5000 cycles |
| Maximum Wear Loss (Samples 1 & 3) | 40 | mg | Weight loss after 5000 cycles |
| Gloss Measurement Angle | 20 | ° | Used for surfaces with mirror sheen |
| Gloss Value (Sample 1) | 62 | GU | Gloss Unit |
| Gloss Value (Sample 3) | 74 | GU | Highest gloss value recorded |
Key Methodologies
Section titled “Key Methodologies”The study characterized the nanodiamond chrome coatings using established material science techniques, focusing on thickness, porosity, hardness, wear, and gloss.
- Coating Deposition: Nanodiamond particles were co-precipitated with chromium during the electroplating process to form the composite coating.
- Thickness Measurement: Coating thickness was precisely determined using an OLYMPUS LEXT OLS4100 confocal laser scanning microscope.
- Porosity Determination (Filter Paper Method):
- Filter paper was immersed in Solution 32 (Potassium iron-hydrogen-3 g/dm3; Sodium chloride-10 g/dm3).
- The saturated paper was applied to the sample for 5 minutes, ensuring no air gap.
- The paper was removed, washed with distilled water, dried, and inspected for blue dots (indicating pores).
- Microhardness Testing (Vickers Method):
- A Vickers hardness tester was used with a 0.5 kg load (HV0.2).
- A tetrahedral diamond pyramid (apex angle 136°) was pressed into the sample surface for 10-15 seconds.
- Microhardness was calculated based on the imprint area using the formula HV = 0.19 P / d2.
- Wear Resistance Testing (Taber Rotational Abrasimeter):
- Samples were secured on a rotating pad.
- Abrasive wheels were lowered onto the sample with a 500 g load.
- The test ran for 5000 cycles at a speed of 60 rpm.
- Wear rate was quantified by measuring the weight loss (Wtloss) of the sample.
- Gloss Measurement:
- A gloss meter was positioned perpendicular to the sample.
- Measurements were taken at a 20° angle, suitable for mirror sheen surfaces.
- The final gloss value (GU) was determined by calculating the arithmetic average of three converging results.
Commercial Applications
Section titled “Commercial Applications”The enhanced properties of the nanodiamond chrome coating make it highly suitable for applications requiring superior durability, low friction, and corrosion resistance beyond that offered by traditional hard chrome plating.
- Automotive and Aerospace: Used for parts operating under high friction and abrasive wear, such as engine components, hydraulic cylinders, and landing gear parts, where extended service life is critical.
- Precision Manufacturing and Tooling: Application on measuring instruments, cutting tools, and molds to increase wear resistance and maintain dimensional accuracy over long operational periods.
- Industrial Machinery: Components in heavy machinery, pumps, and valves that require high surface hardness and resistance to corrosive environments.
- Marine and Offshore Equipment: Utilizing the non-porous structure and high corrosion resistance to protect metal parts exposed to saltwater and harsh weather conditions.
- Decorative and Functional Plating: Replacing conventional chrome plating in applications where a combination of high gloss (62-74 GU) and extreme durability is required.
View Original Abstract
Chrome plating is widely used as a protective and decorative coating and to increase the wear resistance of measuring and cutting tools.To improve the properties of the chrome coating, nanosized particles are coprecipitated with it.Since nanodiamond particles possess the properties of diamond, that is, superhardness, low coefficient of friction, high thermal conductivity and chemical inertness, they are used precisely during deposition with chromium.This article presents a study of chromium-diamond coating.Determination of its wear resistance, microhardness, porosity and other indicators.The use of chromium-diamond coating allows to improve to a greater extent the physicomechanical indices of hard chromium plating, as well as to increase corrosion resistance and increase the service life of parts operating under conditions of corrosion wear.