scholarly journals Embedding Behavior of Ceramic Particles in Babbitt Coatings and Its Effect on the Tribological Properties of Low-Pressure Cold Sprayed Coatings

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 769
Author(s):  
Wolfgang Tillmann ◽  
Mohamed Abdulgader ◽  
Leif Hagen ◽  
Steffen Hüning
Keyword(s):  
Composite Coatings ◽  
Decisive Role ◽  
Low Pressure ◽  
Cold Gas Dynamic Spraying ◽  
Hard Particle ◽  
Friction Behavior ◽  
Splat Formation ◽  
Nozzle Clogging ◽  
Hard Particles ◽  
Coating Microstructure

The low melting point of Sn-based Babbitt alloys often causes nozzle clogging in the low-pressure cold gas-dynamic spraying (LPCGDS) process, which impacts the process steadiness and the coating quality. Adding hard particles to the feedstock material eliminates this kind of interruption. A certain amount of these particles finds their way in the obtained coatings. These particles also trigger a kind of “hammering effect” due to their impulse forces. These forces are directly dependent on the mass and velocity of the impacting hard particles. However, these forces may lead to a decrease in the porosity and improve the adhesion of the obtained coating. In this study, the effect of the density and size of the hard particle was examined by three different hard materials, Cr3C2, Al2O3, and B4C, which have a material density of 6.68, 3.95, and 2.52 g/cm3, respectively. The used feedstock in this study is a powder mixture that contains 75 vol.% Babbitt and 25 vol.% of either B4C, Cr3C2, or Al2O3. The effect of the size distributions “particles with lower mass” was tested using two different Al2O3. The various hard particles show different embedding behaviors, as well as different effects on the coating build-up. It was found that the blended hard particles were enclosed with the Babbitt matrix, and their interface with Babbitt shows no clear evidence of pronounced diffusion. The size distribution of the blended hard particles has a direct effect on the splat formation and the obtained coating microstructure. It was found that the type of hard particles played a decisive role in the friction behavior. Nevertheless, the hard particle reinforced Sn-Sb-Cu-based composite coatings demonstrated a nearly constant coefficient of friction throughout the load-interval.

Development of Metal-Ceramic-Lubricant Composite Coatings Obtained by Cold Spray for Tribological Applications in the Automotive Industry

2021 ◽  
Author(s):  
G. Garcin ◽  
F. Delloro ◽  
M. Jeandin ◽  
J-F. Hochepied ◽  
C. Grente ◽  
...  
Keyword(s):  
Automotive Industry ◽  
Composite Coatings ◽  
Solid Lubricants ◽  
Friction Reduction ◽  
Hard Particles ◽  
Wide Range ◽  
Metal Ceramic ◽  
Coating Microstructure ◽  
Steel Substrates ◽  
The Relationship

Abstract One of the main levers to reduce CO2 emissions in cars and trucks is mass and friction reduction, which is often achieved through the use of special coatings. The aim of the present work was to develop metal-ceramic-lubricant composite coatings with the best combination of wear, seizure, fatigue, and thermal resistance. Metal-based coatings incorporating hard particles and solid lubricants were cold sprayed onto steel substrates and the relationship between coating microstructure and tribology was studied. To meet the demanding tribological requirements of heavily loaded engines, the interfaces between the different components were optimized by selecting appropriate feedstock powders and assessing a wide range of process parameters. Alumina-reinforced bronze composite coatings were made from powders with different morphologies. Aggregated ceramic powders were found to be more beneficial in terms of wear than massive powders, and graphite was found to be effective for reducing seizure.

scholarly journals Improving the microstructure and mechanical properties of laser cladded Ni-based alloy coatings by changing their composition: A review

2020 ◽  
Vol 59 (1) ◽  
pp. 340-351
Author(s):  
Lin Yinghua ◽  
Ping Xuelong ◽  
Kuang Jiacai ◽  
Deng Yingjun
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
Composite Coatings ◽  
Single Element ◽  
Properties Of Coatings ◽  
Hard Particles ◽  
Microstructure And Mechanical Properties ◽  
Nickel Based Alloy

AbstractNi-based alloy coatings prepared by laser cladding has high bonding strength, excellent wear resistance and corrosion resistance. The mechanical properties of coatings can be further improved by changing the composition of alloy powders. This paper reviewed the improved microstructure and mechanical properties of Ni-based composite coatings by hard particles, single element and rare earth elements. The problems that need to be solved for the particle-reinforced nickel-based alloy coatings are pointed out. The prospects of the research are also discussed.

Electroless Nickel-Phosphorus Composite Coatings

2016 ◽  
Vol 6 (1) ◽  
pp. 14-50 ◽  
Author(s):  
Prasanna Gadhari ◽  
Prasanta Sahoo
Keyword(s):  
Corrosion Resistance ◽  
Tribological Properties ◽  
Composite Coatings ◽  
Electroless Nickel ◽  
Friction Behavior ◽  
Factors Affecting ◽  
Conductive Materials ◽  
Mechanical And Tribological Properties ◽  
Coating Methods ◽  
Soft Particles

Electroless nickel composite coatings possess excellent mechanical and tribological properties such as, hardness, wear and corrosion resistance. Composite coatings can easily be coated not only on electrically conductive materials but also on non-conductive materials like as fabrics, plastics, rubber, etc. This review emphasizes on the development of electroless nickel composite coatings by incorporating different types of hard/soft particles (micro/nano size) in the electroless Ni-P matrix to improve the mechanical and tribological properties of the coatings. The preparation of electroless bath for nickel-phosphorus composite coating, methods to incorporate hard and/or soft particles in the bath, factors affecting the particle incorporation in the coating and its effect on coating structure, hardness, wear resistance, friction behavior, corrosion resistance, and mechanical properties are discussed thoroughly.

Study of Damage Mechanisms in Cold-Sprayed 316L-Matrix Composite Coatings Using Novel Impact-Sliding Testing

2014 ◽  
Vol 922 ◽  
pp. 452-462 ◽  
Author(s):  
R. Maestracci ◽  
N. Fabrègue ◽  
M. Jeandin ◽  
G. Bouvard ◽  
M. Messaadi ◽  
...  
Keyword(s):  
Cold Spray ◽  
High Performance ◽  
Composite Coatings ◽  
Industrial Applications ◽  
Damage Mechanisms ◽  
Coating Composition ◽  
Before And After ◽  
Coating Microstructure ◽  
Service Conditions ◽  
Sliding Test

Cold spray is now well recognized as one of the most powerful and efficient coating process because it is cost-attractive and “green”. However, this process still shows limitations to achieve coatings for highly-demanding service conditions such as those required in certain automotive and/or aircraft applications. Beyond these limitations, cold spray is expected to compete with conventional P/M routes.The present work therefore focussed on the study of damage mechanisms in cold-sprayed AISI 316L and 316L-matrix–Cu composites coatings due to high-loading conditions. Different damage mechanisms could occur depending on the content of Cu particle addition, due to changes in the response of the microstructure to the loading. These mechanisms were studied using the newly-developed “impact-sliding” test. In this test, a steel ball impacts the coating surface at a given frequency, with a fixed angle. The influence of major testing parameters was investigated.Microstructures before and after testing were studied using optical microscopy, scanning electron microscopy (SEM), and microprobe analysis in addition to 3D optical profilometry of impacted areas. Damage mechanisms were seen to be of two types, i.e. plastic deformation and wear. These resulted in decohesion of splats, formation of wear debris and formation of a layer with a tribologically-transformed structure (TTS) at the contact surface.Results showed that cold spray could be claimed to be suitable for the achievement of high-performance coatings for industrial applications provided that the coating microstructure can be controlled. This could be done using a composite approach to the coating composition.

Tribocorrosion characteristics of Ti6Al4V-TiB-TiN in-situ composite coatings prepared using plasma spraying

2020 ◽  
pp. 002199832098112
Author(s):  
Akrity Anand ◽  
Mitun Das ◽  
Biswanath Kundu ◽  
Vamsi Krishna Balla ◽  
Subhadip Bodhak ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Strong Influence ◽  
Dominant Role ◽  
Composite Coatings ◽  
High Hardness ◽  
Alloy Composite ◽  
Material Loss ◽  
In Situ Composite ◽  
Coating Microstructure

Ti6Al4V alloy composite coatings in-situ reinforced with TiB-TiN were deposited on Ti substrate using plasma spraying. Influence of plasma power (50 and 60 kW) and deposition speed (40 and 50 mm/s) on coating microstructure and bio-tribocorrosion performance was analyzed. Process parameters found to have strong influence on the tribocorrosion behavior and the material loss/damage of these coatings was found to be significantly less than that of Ti substrate. However, corrosion played a dominant role in affecting the wear and overall damage of all materials. Present in-situ composite coatings reinforced TiB-TiN exhibited superior tribocorrosion resistance than Ti substrate as a result of their high hardness and non-passivating nature.

Effects of External Hard Particles on Brake Friction Characteristics During Hard Braking

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
M. K. Abdul Hamid ◽  
G. W. Stachowiak
Keyword(s):  
Standard Deviation ◽  
Friction Coefficient ◽  
Contact Area ◽  
Oscillation Amplitude ◽  
Stopping Time ◽  
Hard Particle ◽  
Friction Coefficients ◽  
Hard Particles ◽  
Effective Contact ◽  
Friction Oscillation

The effects of external hard particles on the friction coefficients and its oscillation amplitudes during hard braking were investigated. Silica sands of the size between 180 to 355 μm were used during the experiments. The results were compared to the results obtained without the grit particles present in order to determine the change in friction coefficient and the fluctuation of frictional oscillation amplitude. Different sliding speeds were applied and external hard particle of different size is found to significantly affect the friction coefficient and standard deviation of friction oscillation amplitude values. The friction coefficients increase with hard particle due to the rapid changes of the effective contact area and the abrasion mode. Some embedded particles operating in two body abrasion mode help to increase the disc surface roughness and influence the stopping time of the disc. The standard deviation values of friction oscillation amplitude however were stable due to more wear debris produced and get compacted to form friction films assisting friction and they tend to reduce at medium speeds because many contact plateaus and effective contact area started to stabilize.

Microstructure and properties of cold sprayed composite coatings

2017 ◽  
Vol 2 (81) ◽  
pp. 49-55
Author(s):  
A. Góral ◽  
W. Żórawski ◽  
M. Makrenek ◽  
S. Kowalski
Keyword(s):  
Design Methodology ◽  
Wide Spectrum ◽  
Composite Coatings ◽  
Young Modulus ◽  
Lower Surface ◽  
Al Alloy ◽  
Hard Particles ◽  
Ni Powder ◽  
Powder Particles ◽  
Alumina Addition

Purpose: The composite coatings containing incorporated ceramic achieve a wide spectrum of enhanced properties, resulting from a combination of features from a ductile matrix and hard particles. This article attempts to explain how the alumina addition to Ni powder influences the microstructure and mechanical properties of the composite Ni-Al2O3 coatings cold sprayed on the 7075 Al alloy. Design/methodology/approach: The coatings were formed during a deposition of the powder particles step by step which impacts with high velocities onto the substrate, deform, and adhere to it or to other particles. Findings: The incorporation of Al2O3 in the Ni matrix induced a larger plastic deformation of the powder particles and reduced the porosity of the coatings. The Ni-Al2O3 coatings were characterized by a lower surface roughness compared to Ni deposits. The Young modulus of the Ni-Al2O3 coatings were found to be higher than Ni coating.

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