Development of Fe-P Matrix Composites Containing Embedded Solid Lubricants

2014 ◽  
Vol 802 ◽  
pp. 96-101
Author(s):  
Antonio Itamar Ramos Filho ◽  
Renan Schroeder ◽  
Cristiano Binder ◽  
Aloisio N. Klein

In this work the processing of composites containing graphite or hexagonal boron nitride dispersed in a ferrous matrix alloyed with phosphorous was addressed, with the goal of developing self-lubricating sintered materials with high mechanical resistance. Phosphorous is an alloy element characteristic in powder metallurgy for promoting the formation of liquid phase and alpha phase at high temperature, wherein both phenomena are densification inducers. It is expected therefore with that to rearrange volumetrically the solid lubricant reservoirs, so permitting the composites to present better mechanical properties. In order to understand what really occurs at high temperature, sintering was studied in situ in a dilatometer. Furthermore, microstructural and mechanical properties were carried out to characterize the sintered parts. The main remark was that graphite reacts with the matrix going into solid solution and therefore not being disposed as solid lubricant after sintering. On the other hand, h-BN remains insoluble in the Fe-P matrix and without reducing drastically the strength of the composite.

2007 ◽  
Vol 546-549 ◽  
pp. 2273-2278 ◽  
Author(s):  
Yan Jun Wang ◽  
Zuo Min Liu

A new cermet sinter with sweat-gland micro-pore structure has been developed by powder metallurgy technology in vacuum. The effects of the pore-forming materials on micro-pore structure and Y2O3 additions as well mechanical properties of TiC/FeCrWMoV cermets were investigated. Some typical sweat-gland micro-pores were formed while compound additives TiH2 and CaCO3 adding into the sinter matrix. The porosity of the cermet sinters changes from 20% to 28% with the compound additives from 6% to 8%, and the micro-pores of sinters exist a regularized and interpenetrated network structure just like human’s sweat-gland one and obeying to Rayleigh Distribution. As such the sinters could be easily infiltrated with high-temperature solid lubricant. For improving the property of the ceramet sinter, the elements Y2O3 of 0.6~0.8% (vol. fraction ) was also added into the sinter matrix and its effect on the sinter has been also discussed .


2007 ◽  
Vol 546-549 ◽  
pp. 563-566
Author(s):  
Wen Jiang Ding ◽  
Guo Hua Wu ◽  
Bong Sun You ◽  
Dong Yim Chang

The effects of CeCl3-containing fluxes on RE element loss, the high temperature mechanical properties, microstructure and corrosion properties of magnesium alloy containing RE have been studied. The results showed that a certain amount of CeCl3 in purification fluxes restrained the reaction between the Ce element and fluxes to decrease the loss of Ce in alloys. With the flux containing 9% CeCl3, the loss rate of alloy element Ce can be reduced from 26.9% to 3.4%, and the σb and δ of the alloys at 150°C counld be improved from 160.9MPa and 6.2% to 176.5MPa and 7.9% compared with that of conventional MgCl2-containing flux , respectively. Besides, the coarse β phase and rod-like RE phase were refined effectively by CeCl3-containing fluxes.


2021 ◽  
Author(s):  
M. Oechsner ◽  
T. Engler ◽  
H. Scheerer ◽  
Y. Joung ◽  
K. Bobzin ◽  
...  

Abstract High-velocity oxyfuel (HVOF) sprayed coatings of Cr3C2-NiCr containing solid lubricants such as nickel cladded graphite and hexagonal boron nitride were successfully developed and characterised with the aim of optimizing their friction and wear behaviour. HVOF technology was used for the integration of solid lubricants to achieve strong cohesion between particles while minimizing thermal decomposition. Coating microstructure and composition were measured and correlated to the results of tribological and corrosion tests. The integration of the solid lubricant greatly reduced friction and wear volume at room temperature, but the lubricating effect was highly dependent on atmosphere and temperature. Cr3C2-NiCr with hBN, however, tends to exhibit more stable wear resistance over a wider temperature range and can be used at temperatures beyond 450 °C.


Author(s):  
Jianliang Li ◽  
Dangsheng Xiong ◽  
Yongkun Qin ◽  
Rajnesh Tyagi

This chapter illustrates the effect of the addition of solid lubricants on the high temperature friction and wear behavior of Ni-based composites. Ni-based composites containing solid lubricant particles both in nano and micrometer range have been fabricated through powder metallurgy route. In order to explore the possible synergetic action of a combination of low and high temperature solid lubricant, nano or micro powders of two or more solid lubricants were added in the composites. This chapter introduces the fabrication of the Ni-based self-lubricating composites containing graphite and/or MoS2, Ag and/or rare earth, Ag and/or hBN as solid lubricants and their friction and wear behavior at room and elevated temperatures. The chapter also includes information on some lubricating composite coatings such as electro-deposited nickel-base coating containing graphite, MoS2, or BN and graphene and their tribological characteristics.


Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 167 ◽  
Author(s):  
Omid Khalaj ◽  
Ehsan Saebnoori ◽  
Hana Jirková ◽  
Ondřej Chocholatý ◽  
Jiří Svoboda

Fe–Al–O-based materials are currently undergoing a great deal of development because of their many special properties. However, lack of strength at high temperatures, limited ductility at ambient temperatures and corrosion resistance have hindered a wider application of these materials. Recently, a new Fe–Al-based oxide precipitation hardened (OPH) steel was developed by the authors to improve the mechanical properties and oxidation resistance. The new OPH alloys are produced by dissolving a specific amount of oxygen in the matrix during mechanical alloying followed by precipitation of fine dispersion of aluminum or yttrium oxides during hot consolidation. A series of tests was performed to evaluate the thermomechanical properties and corrosion resistance in a 3.5% NaCl solution. The results show improved corrosion resistance, as well as mechanical properties, while the production costs of this material are lower than for traditional materials.


2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Yanming Wang ◽  
Peng Cai ◽  
Tingmei Wang ◽  
Qihua Wang

Tribological and mechanical properties of aramid fiber (AF), graphite (Gr), and hexagonal boron nitride (h-BN) hybrid polyimide composites were investigated under room and high temperature. Results show that, Gr in composite reinforced with AF and h-BN can reduce coefficient of friction (COF) and improve antiwear property of composites under room temperature. Gr can accelerate the formation of transfer film under high temperature without sacrificing the wear resistant of composites. Transfer film of composites reinforced with Gr and h-BN simultaneously present more smooth and uniform compared with that of composites reinforced with only AF and h-BN. However, under higher temperature, composite reinforced with pure Gr present higher COFs and wear rates (WRs) compared with composites filled with h-BN and Gr simultaneously. Comprehensively, composite filled with 10% AF, 3% h-BN, and 4% Gr is the optimum composition.


1990 ◽  
Vol 112 (2) ◽  
pp. 259-265 ◽  
Author(s):  
M. M. Khonsari ◽  
S. H. Wang ◽  
Y. L. Qi

The purpose of this research is to extend the theory of the concentrated thermo-elastohydrodynamic line contact to include the influence of the existence of solid lubricant dispersed in liquid-base lubricant. The combined effects of the rheological characteristics of the oil and the mechanical properties of the particles and those of the bounding surfaces are taken into consideration in theoretical development. Results are presented for the pressure distribution, the oil film thickness, the temperature rise, and the coefficient of friction for two commonly used solid lubricants namely MOS2 and graphite.


Friction ◽  
2020 ◽  
Author(s):  
Wenjuan Huai ◽  
Chenhui Zhang ◽  
Shizhu Wen

AbstractHigh-temperature solid lubricants play a significant role in the hot metal forming process. However, preparing high-temperature solid lubricant is formidably challenging due to the stern working conditions. Here we successfully develop a new type of eco-friendly high-temperature graphite-based solid lubricant by using amorphous silica dioxide, aluminum dihydrogen phosphate, and solid lubricant graphite. The solid lubricating coating exhibits excellent tribological properties with a very low friction coefficient and good wear protection for workpiece at high temperature under the air atmosphere. An array of analytical techniques reveals the existence of solid lubricant graphite in the lubricating coating after the high-temperature friction test. A synergistic effect between the protective surface film and the solid lubricant graphite is proposed to account for such superior lubricating performance. This work highlights the synergistic effect between the protection layer and the lubricant graphite and further provides the insight in designing the high-temperature solid lubricant.


2009 ◽  
Vol 610-613 ◽  
pp. 537-541 ◽  
Author(s):  
Yan Fu Yan ◽  
Li Fang Feng ◽  
Xiao Xiao Guo ◽  
Kun Tang ◽  
Ke Xing Song

It is a difficult subject to develop the high temperature solder with thewhose melting point is within 250~450°C in solder field. Bi5Sb solder alloy whosewith the melting point of about is about 280°C is limited for itshas bad solderability and mechanical properties. In the present work, the new BiSbCu ternary alloy wasis preparformed by adding different contents of Cu to Bi5Sb solder alloy to improve its solderability and mechanical properties. Results showed that the effect of adding 0.5~5.0%Cu into Bi-5Sb on the melting point of Bi5Sb solder alloy wais not distinct , but its solderability and mechanical properties weare markedly improved. Compared to the matrix of Bi5Sb, the spreading area of solder alloy wais about 57.8% largbigger and the tensile strength wais about 212.4% highbigger when the content of Cu wais 1.5wt.%. Analysis of tThe microstructure showeds that the needle-like Cu2Sb gradually becaomes shorter and dense along with the increasing of the content of Cu, which can effectaffected the properties of the solder alloy.


2017 ◽  
Vol 898 ◽  
pp. 711-718 ◽  
Author(s):  
Cheng He ◽  
Bao Liang Shi ◽  
Wen Sheng Li ◽  
Jian Ping Zhao ◽  
Kai Xu ◽  
...  

The influence of long time service on the microstructure and high temperature mechanical properties of T23 steel was studied by optical microscopy, scanning electron microscopy, transmission electron microscopy and tensile testing machine. Results showed that lathy bainite ferrite disappears with the increasing service time, both the size and number of the carbides increases, and M23C6 carbides transform into M6C carbides rich in W element. The service process also has a significant influence on the recovery. Sub-grains were found at the grain boundaries with little dislocations in the matrix after 27448 h service time. After running for 27448 h the microstructure degradation of T23 steel is serious. High temperature tensile properties of T23 are closely related to the alloy aging degree. The reasons for the decrease of high temperature mechanical properties after long time service included microstructure degradations such as the increase of both the size and quantity of M23C6 carbides, the transformation of M23C6 to M6C, the desolution of Cr,W,and Mo elements, the decrease of the dislocation density and the occurrence of the sub-grains.


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