Tribological Properties of Hot-Pressed SrSO4 Ceramic at Elevated Temperatures in Dry Sliding Against Alumina Ball

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Chong-Chong Mao ◽  
Yu-Feng Li

SrSO4 ceramic was prepared by hot-pressed sintering and its friction behavior was investigated against the Al2O3 ball under the dry sliding condition from room temperature to 800 °C. From room temperature to 400 °C, the tribological properties of SrSO4 ceramic are quite poor with the friction coefficients of 0.65–0.83 and the wear rates of about 10−3 mm3/Nm. With the testing temperature increasing to 600 °C and 800 °C, a brittle to ductile transition of SrSO4 takes place because of the activated slip systems. The friction coefficient and wear rate of SrSO4 ceramic also obviously decrease to 0.37 and about 10−4 mm3/Nm at 800 °C. The significant improvement of the tribological properties is ascribed to the formation of a smooth and continuous SrSO4 lubricating film with excellent ductility and low shear strength at elevated temperature. SrSO4 is considered to be a potential candidate for high-temperature solid lubricant with excellent lubricity.

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1589 ◽  
Author(s):  
Mazin Tahir ◽  
Abdul Samad Mohammed ◽  
Umar Azam Muhammad

The effect of various operational factors, such as sliding speed, normal load and temperature on the tribological properties of Date palm fruit syrup (DPFS) as an environmentally friendly lubricant, is investigated. Ball-on-disc wear tests are conducted on mild steel samples in the presence of DPFS as a lubricant under different conditions and the coefficient of friction and wear rate are measured. Scanning electron microscopy, stylus profilometry, and Fourier transform infrared spectroscopy are used to evaluate the wear tracks to determine the underlying wear mechanisms. Results showed that DPFS has excellent tribological properties in terms of low friction and low wear rates making it a potential candidate to be used as a lubricant in tribological applications.


2013 ◽  
Vol 834-836 ◽  
pp. 644-648
Author(s):  
Bin Cai ◽  
Hua Bing Li ◽  
Ye Fa Tan ◽  
Hong Wei Li ◽  
Qi Feng Jing ◽  
...  

The graphite/CaF2/TiC/Ni-base alloy composite coating was prepared on the surface of 45 carbon steel by plasma spray. Effects of loads, friction counterparts and lubricants on the tribological properties of the composite coating were investigated. The results show that the wear rate of the GCTN composite coating against Si3N4is 0.67×10-3mm3/m, which is about 2 times that against GCr15 steel, because Si3N4induces micro-cutting wear of the composite coating. Water and NaCl solution may induce increasing of friction coefficients and wear rates. Especially, wear rate of the GCTN composite coating in NaCl solution is increased by 3.1 times compared with those under dry sliding and water. The GCTN composite coating presents better anti-wear property than Ni-base alloy coating in different environmental mediums.


2013 ◽  
Vol 668 ◽  
pp. 3-8 ◽  
Author(s):  
Jian Rong Sun ◽  
Chang Sheng Li ◽  
Hua Tang ◽  
Zhi Cheng Guo ◽  
Jin Ying Zi Liu

The composites of Ni-W-Cr-Fe-Cu-MoS2-Graphite with nano-MoS2 were prepared by powder metallurgy. Its tribological properties were investigated using the UTM-2 Nano+Micro Tribometer from room temperature to 600°C. The effects of amount of MoS2 and Ni-W-Cr prealloy powder, load, and temperature on the tribological properties were investigated and discussed. The results indicated that the addition of 43~45wt.% Ni-W-Cr prealloy powder had a strengthening effect on the hardness, anti-press and tensile strength. The tensile strength of the composite decreases with the addition of Nano-MoS2 and graphite, and the friction coefficient decrease with increase of the additives over the wide temperature range of 25°C∼600°C. The friction coefficients and wear rates of the composites reach the optimization value at 2.5wt.% MoS2,While its wear rates increase with the increasing temperature and load.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abhishek Vyas ◽  
Kawaljit Singh Randhawa

Purpose The purpose of this study is to improve the mechanical and tribological performance of polypropylene (PP) material. The influence of hexagonal boron nitride (h-BN) microparticles on mechanical and tribological properties of PP/polyamide 6 (nylon 6) (PA6) blend has been investigated in this paper. Design/methodology/approach Tensile strength, elongation, elastic modulus and Rockwell hardness were measured to identify the mechanical properties of materials. Coefficient of friction (COF) and wear rates of materials were measured with the help of a pin-on-disc tribometer to check the tribological behavior of blend and composite materials. Findings As a result, a small decrease in tensile strength and elongation and improvement in elastic modulus were found for PP/PA6 and PP/PA6/h-BN composite compared to pure PP. The wear rate of PP/PA6 blend and PP/PA6/h-BN composite was found low compared to pure PP matrix, while the COF of PP/PA6 blend was found slightly higher owing to the presence of harder PA6 matrix which was then improved by the h-BN filler reinforcement in PP/PA6/h-BN composite. The addition of PA6 in PP improved the wear rate of PP by 8–24%, whereas the addition of h-BN microparticles improved the wear rate by 22–50% and 24–44% compared to pure PP and PP/PA6 blend, respectively, in different parameters. Originality/value Modulus of elasticity and hardness of pure PP was enhanced by blending with PA6 and was further improved by h-BN fillers. The addition of PA6 in PP improved the wear rate, while h-BN fillers were found effective in reducing the COF by generating smooth thin lubricating film.


2007 ◽  
Vol 330-332 ◽  
pp. 1215-1218 ◽  
Author(s):  
Jian Kong ◽  
Dang Sheng Xiong ◽  
Jian Liang Li ◽  
Qun Xing Yuan

Metallic biomaterials are used as bone plate, dental implant, wire, electrode, and so on. For the purpose of providing the medical services with higher quality, the frictional and wear behavior of Cu47Ti34Zr11Ni8, (Cu47Ti34Zr11Ni8)99Si, Zr41Ti14Cu12.5Ni10Be22.5 and Zr57Nb5Cu15.4Ni12.6Al10 bulk metallic glasses (BMG) against ceramic ( Si3N4) at room temperature under dry sliding and lubrication of fresh plasma, distilled water, and physiological saline conditions were investigated on a pin-on-disc testing machine. Under identical sliding condition, the steady state friction coefficients of BMGs were observed with values ranging from 0.6 to 0.9 under dry sliding, 0.5 to 0.8 under lubrication with distilled water, 0.5 to 0.7 under lubrication with physiological saline, and 0.3 to 0.7 under lubrication with fresh plasma, respectively. Wear rates of BMGs indicated significant difference that the Cu-based metallic glasses exhibited higher wear resistance than that of Zr-based glasses. The surface tracks indicated the existence of viscous flow and the material transfer occurred from BMG rod to the ceramic disc. Since tribological properties are not intrinsic properties, those results demonstrated the influences of the environment and the characteristics of BMGs on the frictional behaviors, and furthermore indicated that BMGs may be one of the promising biomaterials in the future.


1947 ◽  
Vol 20 (2) ◽  
pp. 515-524
Author(s):  
A. M. Borders ◽  
R. D. Juve

Abstract For several years work has been carried on here to evaluate a large number of diene polymers and copolymers as rubberlike materials. The writers have observed that changes in polymer composition which result in improved tensile strength and crack-growth resistance of the vulcanizate cause an increase in low temperature stiffness and a rise in brittle point. This generalization seems to apply to tensile values measured at elevated temperatures as well as to those at room temperature. For example, a butadiene copolymer of dichlorostyrene can be made which, as a tread type of vulcanizate, exhibits a tensile strength of over 1500 pounds per square inch at 93° C, in comparison with 800 to 1000 pounds per square inch for GR-S in the same test tread formula at the same temperature. The brittle point of the butadiene-dichlorostyrene rubber, however, is −35° C or higher. GR-S treads in the same test have brittle points between − 55° and −60° C. Probably of greater practical importance is the fact that the vulcanizate with the higher brittle point is stiffer at temperatures well above the brittle point. The purpose of this investigation was to determine to what extent the maximum tensile strength of tread stocks of several synthetic rubbers varies with the temperature difference between the brittle point and the tensile testing temperature of each rubber. These data can then be used to judge the validity and extent of the general observation that changes in copolymer composition which increase strength also raise the brittle point.


2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Zhaoli Liu ◽  
Hang Li ◽  
Jianliang Li ◽  
Jiewen Huang ◽  
Jian Kong ◽  
...  

Abstract In this study, the Mo-alloyed HfN films were prepared by DC-magnetron sputtering and studied their tribological properties at 25–600 °C under dry friction conditions. The relationship between H/E value and tribological properties at elevated temperature was illustrated. A single solid-solution phase was formed for all Hf-Mo-N films which with an FCC structure, and the H/E and H3/E2 values are increased. The film with x = 0.56 obtained a lower friction coefficient (0.4) and wear-rate (1.23 × 10−6 mm3/N m) at room temperature. At elevated temperature, this film maintained high structure stability, meanwhile, a dense and continuous oxide layer with lubrication was formed and tightly covered on the worn surface, that it obtained a lower coefficients of friction and better wear resistance.


2019 ◽  
Vol 29 (3) ◽  
pp. 1426-1438 ◽  
Author(s):  
Tomasz Moskalewicz ◽  
Sławomir Zimowski ◽  
Aleksandra Fiołek ◽  
Alicja Łukaszczyk ◽  
Beata Dubiel ◽  
...  

Abstract This paper describes ways of improving the tribological properties of the Ti-6Al-4V titanium alloy at room and elevated temperatures by electrophoretic deposition of Al2O3/PEEK708 composite coatings and post-heat treatment. The microstructure of the coating components and the coatings was examined by scanning and transmission electron microscopy as well as x-ray diffractometry. The influence of cooling rate after heating of the coated alloy on the PEEK structure and coating surface topography was investigated. It was found that slow cooling with a furnace produced a semi-crystalline structure, whereas fast cooling in water generated an amorphous polymer structure. The semi-crystalline coatings exhibited a more developed surface topography than the amorphous ones. The coatings with a semi-crystalline structure revealed higher scratch resistance than the amorphous ones. The corrosion resistance of the uncoated and coated specimens was examined using electrochemical techniques in a 3.5 wt.% NaCl aqueous solution. Both coatings increased the corrosion resistance of the alloy. The friction and wear properties of the coated specimens against an alumina ball in dry sliding contact at room temperature and elevated temperatures of 150 and 260 °C at ball-on-disk were examined. Both amorphous and semi-crystalline coatings increased the wear resistance and decreased the friction coefficient of the titanium alloy at room temperature. In addition, the semi-crystalline coating was also very effective in improving the titanium alloy’s tribological properties at elevated temperatures. The obtained results clearly show that the composite alumina/PEEK coatings are promising for tribological applications in mechanical engineering.


NANO ◽  
2018 ◽  
Vol 13 (04) ◽  
pp. 1850035 ◽  
Author(s):  
Tong Chen ◽  
Lihua Yu ◽  
Hongbo Ju ◽  
Junhua Xu ◽  
Shinji Koyama

A series of ZrN–Cu nano-composite films were deposited using the RF magnetron sputtering system. The microstructure, mechanical properties and tribological properties were investigated. The results showed that ZrN–Cu films were composed of face-centered cubice (fcc)-ZrN and face-centered cubic (fcc)-Cu. With the increase of Cu content, the hardness of ZrN–Cu composite film increased slowly first and then decreased rapidly. The maximum hardness value was 34.6[Formula: see text]GPa at 16[Formula: see text]at.% Cu. At room temperature, the coefficient of friction (Cof.) of ZrN–Cu films were lower than the ZrN film. When the content of Cu was lower than 39[Formula: see text]at.%, the wear rate of ZrN–Cu films were lower than the ZrN film. When the temperature of tribological testing was between 200–700[Formula: see text]C, the Cof. of ZrN–Cu films at 16[Formula: see text]at.% Cu were lower than ZrN film, while the wear rates were higher than the ZrN film. In summary, the addition of Cu improved the hardness and tribological properties of the ZrN–Cu film at room temperature, and decreased the Cof. of the ZrN-Cu during 200–700[Formula: see text]C.


Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1629
Author(s):  
Janette Brezinová ◽  
Mária Hagarová ◽  
Dagmar Jakubéczyová ◽  
Gabriela Baranová ◽  
Olegas Prentkovskis

This paper deals with the evaluation of mechanical and tribological properties of Ni-Co galvanic coatings at elevated temperatures. The coatings were deposited on the copper surface, which in practice is the material of the crystallizer. Ni-Co coatings are manufactured to increase the abrasion resistance of the crystallizer surface at elevated operating temperatures. The microhardness (HV0.05) measurements of the coating at 400 °C were used to determine its mechanical properties. The Ball-on-Disc Test was used to determine the tribological properties of the coatings at 400 °C. The mechanical and tribological properties of Ni-Co coatings at elevated temperature were compared to the results of experiments performed at room temperature. When heated to 400 °C, HV0.05 decreased by 9.5 to 22% (depending on Co content in the coating) compared to the values that were measured at 23 °C. The change in the COF for the Ni-Co coating at 400 °C was from 0.680 to 0.750 depending on the Co amount compared to the values at 23 °C. The COF values at room temperature ranged from 0.373 to 0.451. The places with higher wt. % Co had better friction properties than the places with lower wt. % Co.


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