Effect of Sintering Temperature on the Tribological Behavior of Plasma Assisted Debinded and Sintered MIM Self Lubricating Steels

2010 ◽  
Author(s):  
Jose´ Daniel B. de Mello ◽  
Cristiano Binder ◽  
Aloisio Nelmo Klein ◽  
Roberto Binder
Keyword(s):  
Friction Coefficient ◽  
Sintering Temperature ◽  
Metallic Matrix ◽  
Solid Lubricants ◽  
Solid Lubrication ◽  
Metal Injection Molding ◽  
Processing Route ◽  
Second Phase ◽  
New Processing ◽  
Feedstock Preparation

Solid lubrication and solid lubricants are one of the most promising choices for controlling friction and wear in energy efficient modern systems. The production of self lubrication composites containing second phase particles incorporated into the volume of the material appears to be a promising solution. A new processing route to obtaining a homogeneous dispersion of discrete solid lubricant particles in the volume of sintered steels produced by metal injection molding (MIM) was recently presented. This new route was achieved by in situ formation of graphite nodules due to the dissociation of precursor (SiC particles) mixed with the metallic matrix powders during the feedstock preparation. Nodules of graphite (size ≤ 20μm) presenting a nanostructured stacking of graphite foils a few nanometers thick were obtained. The thermal debinding, as well as the sintering, was performed in a single thermal cycle using a Plasma Assisted Debinding and Sintering (PADS) process. In this work, we present and discuss the effect of sintering temperature on the tribolayer durability and average friction coefficient in the lubricious regime (μ<0.2) of plasma assisted debinded and sintered self lubricating steel produced by metal injection mould technique. Three different temperatures (1100, 1150 and 1200 °C) and six different SiC contents (0–5%) were analyzed. Friction coefficient was little affected by the sintering temperature. However, the durability of the tribo layer formed on the sliding interface was greatly increased (5X) for the lower sintering temperature (1100°C).

Characterization of Sintered Bronze–MoS2 Composite With Solid Lubrication Effect

2020 ◽  
Vol 143 (7) ◽  
Author(s):  
L. E. Vieira ◽  
A. L. Gonçalves ◽  
N. I. R. Arraya ◽  
J. B. Rodrigues Neto ◽  
A. Dias ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Metallic Matrix ◽  
Solid Lubricants ◽  
Solid Lubrication ◽  
Material Loss ◽  
Wear Rates ◽  
Sintered Bronze ◽  
Material Wear ◽  
Self Lubricating Composites

Abstract The most efficient method to reduce material loss and frictional energy losses is by using lubrication. An alternative is the use of solid lubrication, specifically by using solid lubricants evenly distributed in a metallic matrix, thus forming self-lubricating composites, which are capable to induce low coefficients of friction in mechanical systems. Molybdenum disulfide (MoS2) is a very versatile solid lubricant, suitable for lubrication in critical circumstances such as vacuum, high temperatures, and pressures. Therefore, the aim of this study is to produce samples of sintered composites consisting of homogeneously distributed MoS2 in a bronze matrix obtained by cold uniaxial pressing and to compare the wear-rates and friction coefficient between the MoS2-free bronze and the self-lubricating composites. Different MoS2 percentages were used to characterize the tribological properties of the composites as a function of the MoS2 content. At the end of the experiments, it was found that samples with 20% MoS2 did not sinter properly due to the large amount of lubricant between the bronze particles. It was also found that the mixture with 5.0 vol% MoS2 had proper sintering, satisfactory hardness, achieved lower friction coefficient, and better material wear performance due to the optimal amount and good distribution of MoS2 when compared with the rest of conditions studied.

Metal Injection Molding Process of Mo2FeB2 Boride Base Cermets

2007 ◽  
Vol 534-536 ◽  
pp. 377-380 ◽  
Author(s):  
Hirofumi Tashiro ◽  
Koro Hirata ◽  
Yuji Yamasaki ◽  
Kenichi Takagi
Keyword(s):  
Mechanical Properties ◽  
Liquid Phase ◽  
Injection Molding ◽  
Sintering Temperature ◽  
Casting Machine ◽  
Dimensional Accuracy ◽  
Metal Injection Molding ◽  
Processing Route ◽  
Injection Molding Process ◽  
Molding Process

Mo2FeB2 boride base cermets produced by a novel sintering technique, called reaction boronizing sintering through a liquid phase, have excellent mechanical properties and wear and corrosion-resistances. Hence, the cermets are applied to the injection molding die-casting machine parts and so on. Metal injection molding (MIM) is a suitable processing route for the mass production of complex shaped and high performance components. In general, it is difficult for the liquid phase sintered materials to be applied to the injection molding process because significant shrinkage and deformation occur during sintering. In this study, the MIM process was applied in the production of Mo2FeB2 boride base cermets parts. We investigated that the effect of deoxidization and sintering temperature on mechanical properties and deformation of the cermets. As a result, deoxidization temperature of 1323K and sintering temperature of 1518K were suitable. The MIM products of the cermets showed allowable dimensional accuracy and the same mechanical properties as the press-sintered.

Formation Mechanisms of Tribo-Coating for Low Friction in UHV

2005 ◽  
Author(s):  
Koshi Adachi ◽  
Hisakazu Sato ◽  
Koji Kato
Keyword(s):  
Friction Coefficient ◽  
Composite Structure ◽  
Solid Lubricant ◽  
Silicon Oxide ◽  
Solid Lubricants ◽  
Solid Lubrication ◽  
Formation Mechanisms ◽  
Coating Film ◽  
Low Friction ◽  
Indium Film

Solid lubrication film formed by tribo-coating, which deposits a solid lubricant by evaporation to the contact interface during friction in vacuum, gives low friction coefficient below 0.03 that can not be observed by any other solid lubricants of soft metals. The tribo-coating film formed on the pin has nano-order composite structure which the crystalline indium of nano size are distributed in an amorphous matrix of silicon oxide and chromium oxide. Because of the nano composite structure, a very thin indium film is formed without break down like conventional pre-coated thin film. The thinner indium film can give smaller value of friction coefficient than that of conventional solid lubricant.

Friction and Wear Behaviors of Solid Lubricants/Polyimide Composites in Liquid Mediums

2010 ◽  
Vol 654-656 ◽  
pp. 2763-2766 ◽  
Author(s):  
Li Wen Mu ◽  
Xin Feng ◽  
Yi Jun Shi ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Alkaline Solution ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricants ◽  
Polyimide Composites ◽  
Inorganic Fillers ◽  
Ptfe Composites

The tribological properties of polyimide (PI) composites reinforced with graphite or MoS2 sliding in liquid alkali and water as well as dry friction were investigated using a ring-on-ring tester. The results show that the friction coefficient (μ) and wear rate (W) for both graphite/PI and MoS2/PI composites in different liquid mediums are μdry>μwater >μalkali and Wwater>Wdry >Walkali. Results also indicate that the friction coefficient and wear rate of the PI composites filled with different solid lubricants are μMoS2 >μgraphite and W MoS2 >Wgraphite in different liquid mediums. In addition, the hydrophobic inorganic fillers are fit for the reinforcement of polymer-based composites sliding in liquid mediums. It is also concluded from the authors’ work that the wear rate and friction coefficient of polymer-based (such as PI, PTFE) composites in the alkali lubricated conditions is lowest among all the friction conditions. This may be attributed to the ionic hydration in the alkaline solution.

Development of Ni/h-BN Self-Lubricating Composite Powder by High-Energy Ball Milling

2016 ◽  
Vol 869 ◽  
pp. 277-282
Author(s):  
Moisés Luiz Parucker ◽  
César Edil da Costa ◽  
Viviane Lilian Soethe
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
Solid Lubricants ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Second Phase ◽  
Average Particle ◽  
Composite Powders ◽  
The Matrix ◽  
Energy Ball

Solid lubricants have had good acceptance when used in problem areas where the conventional lubricants cannot be applied: under extreme temperatures, high charges and in chemically reactive environments. In case of materials manufactured by powder metallurgy, particles of solid lubricants powders can be easily incorporated to the matrix volume at the mixing stage. In operation, this kind of material provides a thin layer of lubricant that prevents direct contact between the surfaces. The present study aimed at incorporating particles of second phase lubricant (h-BN) into a matrix of nickel by high-energy ball milling in order to obtain a self-lubricating composite with homogeneous phase distribution of lubricant in the matrix. Mixtures with 10 vol.% of h-BN varying the milling time of 5, 10, 15 and 20 hours and their relationship ball/powder of 20:1 were performed. The effect of milling time on the morphology and microstructure of the powders was studied by X-ray diffraction, SEM and EDS. The composite powders showed reduction in average particle size with increasing milling time and the milling higher than 5 hours resulted in equiaxial particles and the formation of nickel boride.

Figures of Merit of Low-Cost CuAl0.9Fe0.1O2 Thermoelectric Material Prepared at Different Solid State Reaction Sintering Temperatures

2015 ◽  
Vol 659 ◽  
pp. 185-189
Author(s):  
Aparporn Sakulkalavek ◽  
Rungnapa Thonglamul ◽  
Rachsak Sakdanuphab
Keyword(s):  
Figure Of Merit ◽  
Sintering Temperature ◽  
Low Cost ◽  
Uniaxial Pressure ◽  
Rhombohedral Structure ◽  
Second Phase ◽  
X Ray Diffraction ◽  
High Purity Grade ◽  
Average Grain Size ◽  
Xrd Patterns

In this study, we investigated a CuAl0.9Fe0.1O2 compound prepared at two different sintering temperatures in order to find out the effect of sintering temperature on the compound's figure of merit of thermoelectric properties. The thermoelectric CuAl0.9Fe0.1O2 compound was prepared from high purity grade Cu2O, Al2O3 and Fe2O3 powders. The mixture of these powders were ground and then pressed with uniaxial pressure into pellets. The pellets obtained were sintered in the air at 1423 K and 1473 K. X-ray diffraction (XRD) patterns showed a single phase of CuAl0.9Fe0.1O2 with rhombohedral structure, , along with a trace of CuO second phase. Moreover, the XRD peaks of the sample sintered at 1423 K indicated that more Fe3+ atoms replaced Al3+ atoms in this sample than they did in the sample sintered at 1473 K. The average grain size of the CuAl0.9Fe0.1O2 compound prepared increased with increasing sintering temperature, whereas its mean pore size and porosity decreased with increasing sintering temperature. The dispersed small pores markedly decreased the thermal conductivity of the compound, while the Fe3+ substitution of Al3+ increased its electrical conductivity. The highest figure of merit (ZT) found was 0.021 at 973 K in the CuAl0.9Fe0.1O2 sample sintered at 1423 K. Our findings show that this low-cost material with a reasonable figure of merit is a good candidate for thermoelectric applications at high-temperature.

scholarly journals Bonding evolution with sintering temperature in low alloyed steels with chromium

2009 ◽  
Vol 41 (2) ◽  
pp. 161-173 ◽  
Author(s):  
L. Fuentes-Pacheco ◽  
M. Campos
Keyword(s):  
Carbothermic Reduction ◽  
High Performance ◽  
Sintering Temperature ◽  
Surface Oxide ◽  
Dew Point ◽  
Processing Route ◽  
Initial Surface ◽  
Sintered Steels ◽  
Controlling Mechanism ◽  
Die Compaction

At present, high performance PM steels for automotive applications follow a processing route that comprises die compaction of water-atomized powder, followed by sintering and secondary treatments, and finishing operations. This study examines Cr-alloyed sintered steels with two level of alloying. In chromium-alloyed steels, the surface oxide on the powder is of critical importance for developing the bonding between the particles during sintering. Reduction of this oxide depends mainly on three factors: temperature, dew point of the atmosphere, and carbothermic reduction provided by the added graphite. The transformation of the initial surface oxide evolves sequence as temperature increases during sintering, depending on the oxide composition. Carbothermic reduction is supposed to be the controlling mechanism, even when sintering in hydrogen-containing atmospheres. The effect of carbothermic reduction can be monitored by investigating the behavior of the specimens under tensile testing, and studying the resultant fracture surfaces.

Simulation Study of Granular Compaction Dynamics under Vertical Tapping

2007 ◽  
Vol 555 ◽  
pp. 107-112 ◽  
Author(s):  
D. Arsenović ◽  
S.B. Vrhovac ◽  
Z.M. Jakšić ◽  
Lj. Budinski-Petković ◽  
A. Belić
Keyword(s):  
Numerical Simulation ◽  
Molecular Dynamics ◽  
Friction Coefficient ◽  
Simulation Study ◽  
Material Properties ◽  
Two Dimensions ◽  
Second Phase ◽  
Hard Disks ◽  
Compaction Process ◽  
Granular Compaction

We study by numerical simulation the compaction dynamics of frictional hard disks in two dimensions, subjected to vertical shaking. Shaking is modeled by a series of vertical expansions of the disk packing, followed by dynamical recompression of the assembly under the action of gravity. The second phase of the shake cycle is based on an efficient event−driven molecular−dynamics algorithm. We analyze the compaction dynamics for various values of friction coefficient and coefficient of normal restitution. We find that the time evolution of the density is described by ρ(t)=ρ∞ − ρEα[−(t/τ)α], where Eα denotes the Mittag−Leffler function of order 0<α<1. The parameter τ is found to decay with tapping intensity Γ according to a power law τ ∝ Γ−γ , where parameter γ is almost independent of the material properties of grains. Also, an expression for the grain mobility during compaction process has been obtained.

Preparation and Investigation on Properties of the MgTiO3-CaTiO3 Microwave Ceramic Materials

2014 ◽  
Vol 997 ◽  
pp. 419-423 ◽  
Author(s):  
Li Dong ◽  
Gui Xia Dong ◽  
Yuan Yuan Li ◽  
Xi Zhang
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Ceramic Materials ◽  
Volume Density ◽  
Second Phase ◽  
Pressureless Sintering ◽  
Solid Reaction ◽  
Reaction Method ◽  
Microwave Ceramic ◽  
Sintering Method

The MgTiO3 and CaTiO3 powders were synthesized by solid reaction method, and MgTiO3-CaTiO3 ceramic was prepared using pressureless sintering method. The experiment prepared MgTiO3-CaTiO3 ceramics with high compactness and stable permittivity by the way of changing the mole ratio of MgTiO3 and CaTiO3 to investigate the effect of CaTiO3 on the performances of MgTiO3-CaTiO3 ceramics. The results show that Mg2TiO4 formed as second phase during sintering. Volume density and dielectric constant of MgTiO3-CaTiO3 ceramics with 10%mol CaTiO3 reach maximum of 3.612g/cm3 and 17.8, respectively, under 1460°C sintering temperature. And for the MgTiO3-CaTiO3 ceramics with 5%mol CaTiO3 the maximum values which are 3.5g/cm3 and 16.6, respectively, appear under 1510°C sintering temperature.

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