Effects of Type of Lubricant in Cold Extrusion of Sintered Preforms

1983 ◽  
Vol 105 (2) ◽  
pp. 128-131
Author(s):  
T. Tabata ◽  
S. Masaki ◽  
K. Hosokawa
Keyword(s):  
Copper Powder ◽  
Crack Formation ◽  
Solid Lubricants ◽  
Extrusion Ratio ◽  
Extrusion Pressure ◽  
Cold Extrusion ◽  
Sintered Copper ◽  
Dry Film

Four types of lubricant, i.e., dry film, liquid, powdered solid and liquid with powdered solid lubricants, were evaluated for cold extrusion of sintered copper powder preforms. Effects of the lubricants on extrusion pressure, densification and crack formation were examined with respect to variations of density of the preforms, extrusion ratio and die angle. It was found that liquid and liquid with powdered solid lubricants were not suitable for extrusion of sintered preforms.

Fabrication and capillary characterization of multi-scale micro-grooved wicks with sintered copper powder

2021 ◽  
Vol 121 ◽  
pp. 105123
Author(s):  
Qifan Li ◽  
Zhong Lan ◽  
Jiang Chun ◽  
Shijun Lian ◽  
Rongfu Wen ◽  
...  
Keyword(s):  
Copper Powder ◽  
Multi Scale ◽  
Sintered Copper

Experimental Investigation on Contact Angle of Sintered Copper Powder Wick

2016 ◽  
Vol 819 ◽  
pp. 575-579 ◽  
Author(s):  
Nandy Putra ◽  
Iwan Setyawan ◽  
Dimas Raditya
Keyword(s):  
Contact Angle ◽  
Copper Powder ◽  
High Speed ◽  
Ambient Air ◽  
Video Camera ◽  
High Heat ◽  
High Heat Flux ◽  
Powder Particle Size ◽  
Air Exposure ◽  
Sintered Copper

Heat pipes are widely used in electronic cooling and other applications that require efficient transport or spreading of heat from local sources of high heat flux. One factor that most affect the performance of this device is the wetting properties of the wick material, whereby a hydrophilic wick material is required to transport the liquid from the evaporator to the condenser. The performance of heat pipe will decrease when the wick surface becomes hydrophobic as indicated by changes in its contact angle (CA). This study aims to determine the effect of ambient air exposure on the wettability of wick material. Wettability for a surface by a certain liquid can be shown by measuring the contact angle of liquid droplets on the surface. In this experiment, the contact angle was captured using a high speed video camera followed by image processing and then measured using Image J software. The surface of the sample/wick is a sintered copper powder which in this study through a process of forming or compaction by various parameters such as powder particle size, compacting pressure and sintering temperature. From the results of this study was found that the longer wicks were exposed in the ambient air, the contact angle of the liquid on the wick surface will be getting increased. After 7 days were contaminated on the ambient air, then all samples have been turned into hydrophobic, CA>90°.

The Effect of Process Variables on Extrusion Pressures of Lead

1959 ◽  
Vol 81 (3) ◽  
pp. 207-214 ◽  
Author(s):  
J. Frisch ◽  
E. G. Thomsen
Keyword(s):  
Room Temperature ◽  
Extrusion Ratio ◽  
Extrusion Pressure ◽  
White Lead ◽  
Cylinder Wall ◽  
Process Variables ◽  
Pure Lead ◽  
Commercially Pure ◽  
Wide Range

Billets of commercially pure lead, 2 in. diam × 3 in. long were extruded at room temperature through five different die contours at ram speeds up to 50 ipm. It was found that, for the direct and indirect extrusions, with good lubrication (white lead in oil) and with good cylinder-wall finish, the extrusion pressure-displacement diagrams were essentially the same. The concentric and eccentric single-bar and multibar extrusions at constant extrusion ratio required approximately the same pressures when extruded at identical speeds. The extrusion pressures over the wide range of speeds investigated showed approximate linearity when plotted on log-log co-ordinates.

THE INFLUENCE OF THE TYPE OF GREASE ON THE SYNERGY OF ITS COMPOSITION WITH PTFE POWDER AND COPPER POWDER

Tribologia ◽  
2016 ◽  
Vol 265 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Stanisław KRAWIEC ◽  
Michał KRAWIEC ◽  
Tadeusz LEŚNIEWSKI
Keyword(s):  
Synergistic Effect ◽  
Copper Powder ◽  
Confidence Level ◽  
Solid Lubricants ◽  
Test Results ◽  
Extreme Pressure ◽  
The Third ◽  
Student’S T ◽  
Student’S T Test ◽  
Lubricating Properties

Studies of the influence of the type of grease on the synergistic effect of its compositions with PTFE powder and of copper during the lubrication of steel sliding pairs working in mixed friction area of were presented. Two greases, car grease 1S with a lithium thickener and grease STP with calcium thickener, were adopted for analysis. As fillers in the two lubricants, powders of two solid lubricants were PTFE and copper were used. Three lubricating compositions were tested for each of the adopted greases. Two compositions contained one filler of 5% by weight, and the third composition contained the two fillers in the same proportion (5% each). The lubricating properties of the adopted compositions were evaluated based on an experiment conducted with the use of a four–ball extreme pressure tester according to the standard PN-76/ C04147. The effectiveness of the analysed lubricants was evaluated according to four criterion values (wear of the balls d, fusion point Fz, limit wear load Goz, and wear index Ih). The results were statistically handled at the confidence level of 95% using Student’s t-test. The developed test results are shown graphically. Appropriate conclusions were drawn.

Some aspects of cold extrusion of sintered copper preforms

1986 ◽  
Vol 13 (3) ◽  
pp. 339-364 ◽  
Author(s):  
P. Venugopal ◽  
S. Annamalai ◽  
K.S. Kannan ◽  
Sriram Srinivasan
Keyword(s):  
Cold Extrusion ◽  
Sintered Copper

scholarly journals Investigation on the Tribological Behaviors of as-sprayed Al2O3 Coatings With the Effects of MoS2 Lubricant and External Loads

2020 ◽  
Author(s):  
Wen Deng ◽  
Lin TANG ◽  
Hui QI ◽  
Changfu ZHANG
Keyword(s):  
Mechanical Properties ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Solid Lubricants ◽  
Temperature Sensitive ◽  
Tribological Behaviors ◽  
Lubricating Layer ◽  
External Loads ◽  
Spraying Method ◽  
Dry Film

Abstract The Al2O3-MoS2 ceramic-based lubricating coating was prepared via introducing MoS2 dry film lubricant into the pores and cracks of thermal-sprayed Al2O3 coating by facial paint spraying method. The microstructure, mechanical properties and tribological behaviors of the as-received Al2O3-MoS2 coating were thoroughly evaluated. The results illustrated that MoS2 was mainly concentrated on the shallow surface of the Al2O3 coating, and thus more uniform, more compact and smoother Al2O3-MoS2 coating was obtained. Meanwhile, the mechanical properties of the Al2O3 coating did not change significantly after the introduction of MoS2. The tribological experiments illustrated that compared with the Al2O3 coating, the friction coefficient and specific wear rate of the Al2O3-MoS2 coating under different loads were greatly reduced due to the generation of the lubricating layer. Especially under the load of 5 N, the friction coefficient was as low as 0.36, and the wear rate (1.49×10-5 mm3×(N×m)-1) was almost 17 times lower than that of Al2O3 coating (2.53×10-4 mm3×(N×m)-1). This research established a new and simple way to prepare ceramic-based self-lubricating coatings by using temperature-sensitive solid lubricants.

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