Self-Lubricant Effect of Tri-Oxidizing Layer in Surface of Bulk Ti3SiC2 Materials

2005 ◽  
Vol 475-479 ◽  
pp. 1259-1262 ◽  
Author(s):  
Zhi Li Zhang ◽  
Hong Xiang Zhai ◽  
Zhen Ying Huang ◽  
Yang Zhou ◽  
Shi Bo Li

In this paper, tribological tests for Ti3SiC2 sliding against low carbon steel were made on a block-on-disc type friction tester, with the normal pressures from 0.1 to 0.8 MPa and the sliding speed of 30 to 50 m/s. The surface state was observed and analyzed by SEM and XRD. A definite tribo-glazing layer was found over the worn surface of the Ti3SiC2 block, which seems to be primary reason for Ti3SiC2 to have comparatively lower friction coefficient and wear rate, because the tribo-glazing layer would be fusible under high frictional temperature. The tribo-glazing layer was the results of tribo-chemical oxidation reaction and the cause forming it could be the high frictional temperature and the mechanical catabolism in the surface of Ti3SiC2 during sliding friction. Due to the tribo-oxidation reaction is un-reversible and self-adaptive, the tribo-glazing layer in area and thickness are function of normal pressures and sliding speed.

2005 ◽  
Vol 475-479 ◽  
pp. 1251-1254 ◽  
Author(s):  
Hong Xiang Zhai ◽  
Zhen Ying Huang ◽  
Yang Zhou ◽  
Zhi Li Zhang ◽  
Shi Bo Li ◽  
...  

The friction behavior of a high-purity bulk titanium aluminum carbide (Ti3AlC2) material dryly sliding against low carbon steel was investigated. Tests were performed using a block-on-disk type high-speed friction tester under sliding speed of 20 m/s and 60 m/s, several normal pressures from 0.1 to 0.8 MPa. The results showed that the friction coefficient is as low as about 0.18 for sliding speed of 20 m/s and only 0.1 for 60 m/s, and that almost not changes with the normal pressure. The reason could be related with the presence of a surface layer on the friction surface. The layer was analyzed to consist of Ti, Al and Fe oxides, which played a lubricate part inducing the friction coefficient decrease on the friction surface.


2007 ◽  
Vol 561-565 ◽  
pp. 563-566
Author(s):  
Zhen Ying Huang ◽  
Hong Xiang Zhai ◽  
Hua Zhang ◽  
Hong Bing Zhang

The current-carrying wear characteristics of Ti3AlC2 sliding against low-carbon steel were investigated. Tests were carried out using a block-on-disk type friction tester, with sliding speeds of 20~60 m/s, normal pressures range in 0.4~ 0.8 MPa, and the current intensity of 0 A, 50 A and 100 A. The Ti3AlC2 showed good current-carrying wear properties. At the sliding speed of 20 m/s, the wear rate of the Ti3AlC2 (× 10-6 mm3/Nm) was varied in the range of (2.05 ~ 2.41), (2.64 ~ 2.39) and (6.26 ~ 3.62), under the current of 0 A, 50 A and 100 A, respectively. Both the surfaces of Ti3AlC2 and the steel were covered by a frictional film, which was consisted of iron titanate (Fe2.25Ti0.75O4) and aluminum iron oxide (AlFeO3). The wear rate of Ti3AlC2 with current was composed of two parts: the interaction of micro-arc ablation and mechanical friction, and the coupled action of thermal and mechanical effect. Which one will be the main mechanism depends on the material parameters of Ti3AlC2 and the mechanical parameters such as the normal pressure or the sliding speed.


2007 ◽  
Vol 336-338 ◽  
pp. 1436-1438 ◽  
Author(s):  
Zhen Ying Huang ◽  
Hong Xiang Zhai ◽  
Ming Xing Ai

The tribological behavior of a new cermet Ti3AlC2/Cu was experimentally investigated. The results showed that the Ti3AlC2/Cu was a good tribological material sliding against the low carbon steel, especially for a high sliding speed. The friction coefficient was as low as 0.13 ~ 0.15, and the Ti3AlC2/Cu wear rate was only 3.4×10-6 mm3/Nm, for the sliding speed of 60 m/s and the normal pressure of 0.8 MPa. The forming of a frictional film consisted of Ti, Al, Cu and Fe oxides on the friction surfaces could be a fundamental cause.


2007 ◽  
Vol 280-283 ◽  
pp. 1353-1356 ◽  
Author(s):  
Zhen Ying Huang ◽  
Hong Xiang Zhai ◽  
Yang Zhou ◽  
Yi Fan Wang ◽  
Zhi Li Zhang

The friction behavior of Ti3SiC2 sliding against low carbon steel was studied. Tests were carried out on a block-on-disk type friction tester, with the normal pressures from 0.2 MPa to 0.8 MPa and the sliding speed of 20 m/s. The results showed that, irrespective of the normal pressure, the friction coefficient exhibits a transition period in the initial stage of a sliding friction process, in which the friction coefficient increases from an initial value and tends to a saturation value, and then enters into a relatively steady stage. The results also showed that, the friction coefficient of the steady stage decreases gradually from 0.35 to 0.26 with increase in normal pressure from 0.2 MPa to 0.8 MPa. The friction surfaces were observed by using SEM. It was found that all the surfaces were covered by a layer consisting of the frictional products with antifriction effect, and that the denseness and the thickness of the layer were increased with increase in normal pressure applied.


2008 ◽  
Vol 368-372 ◽  
pp. 989-991 ◽  
Author(s):  
Zhi Li Zhang ◽  
Hong Xiang Zhai ◽  
Yang Zhou ◽  
Zhen Ying Huang ◽  
Ming Xing Ai

Al/Ti3AlC2 composites containing 50vol% Al were prepared with high purity of polycrystalline Ti3AlC2 and aluminum powders by pressureless-sintering route at temperatures of 700°C~ 800°C The tribological properties of the composites were investigated by sliding the composites block dryly against low carbon steel disk under high sliding speed. Before and after friction test, the morphology and phase analysis were observed by scanning electron microscope (SEM) and X-ray diffraction (XRD), separately. A definite tribo-glazing layer was found over the worn surface of the composite block, which was the results of tribo-chemical oxidation reaction and the cause forming it could be the high frictional temperature and the mechanical catabolism between the surface of Al/Ti3AlC2 and low carbon steel during sliding friction. The effect of Ti3AlC2 on tribological properties of Al/Ti3AlC2 composite and the possible tribo-chemical reaction mechanism on surface layer of Al/Ti3AlC2 were suggested.


2007 ◽  
Vol 280-283 ◽  
pp. 1347-1352 ◽  
Author(s):  
Hong Xiang Zhai ◽  
Zhen Ying Huang ◽  
Yang Zhou ◽  
Zhi Li Zhang ◽  
Yi Fan Wang

Characteristics of the frictional layer in high-purity Ti3SiC2 and TiC-contained Ti3SiC2, sliding against low carbon steel, were investigated. The friction and wear tests were made using a block-on-disk type friction tester with sliding speed of 20 m/s and several normal pressures from 0.1 MPa to 0.8 MPa. It was found that all friction surfaces, whether high-purity Ti3SiC2 or TiC-contained Ti3SiC2, were covered by a layer consisting of the oxides of Ti, Si and Fe. The layer was sticky, superimposed layer-by-layer, and the compact was increased with the normal pressure increasing. Because its antifriction effect, the friction coefficient decreases from the maximum 0.35 to 0.27 with increase in the normal pressure from 0.2 MPa to 0.8 MPa for the high-purity Ti3SiC2, and decreases from the maximum 0.55 to 0.37 for the same change of the normal pressure for the TiC-contained Ti3SiC2. The contained TiC grains had effects on the stickiness, liquidness, as well as the morphology of the layer, and induced the friction coefficient to increase in the entire level.


2007 ◽  
Vol 280-283 ◽  
pp. 1357-1360 ◽  
Author(s):  
Zhi Li Zhang ◽  
Hong Xiang Zhai ◽  
Zhen Ying Huang ◽  
Cui Wei Li ◽  
Yi Fan Wang ◽  
...  

The Ti3SiC2 samples with a second phase TiC, prepared by hot-pressing progress route, were rubbed against low carbon steel disk with a sliding speed of 20 m/s under normal pressure 0.8 Mpa in atmosphere on a block-on-disk type friction tester. The morphology was observed by scanning electron microscope (SEM) and meanwhile the composition was checked by energy dispersion spectroscopy (EDS). X-ray diffraction (XRD) patterns show some impurity phases containing Ti, Si and Fe oxides in the samples. The possible tribo-chemical reaction mechanism on surface layer of Ti3SiC2 was suggested.


Author(s):  
Meng Xu ◽  
Jiajun Zhu ◽  
Wulin Yang ◽  
Deyi Li ◽  
Lingping Zhou ◽  
...  

The wear behavior of Ag implantation GH4169 alloy by ion beam assisted bombardment was measured under lower applied load and sliding speed. The wear rate of GH4169 alloy decreased from 2.58 × 10−4 mm3·m−1 to 6.25 ×10−5 mm3·m−1 after Ag implantation. The friction coefficient had not mostly been changed. After Ag implantation, Ag and Ag2O were detected on the worn surface of GH4169 alloy, which benefits the formation of continuous lubrication and protected layers. The predominant wear mechanism changed from abrasion and adhesion wear to oxidation and adhesion wear. In addition, the hardness increased. So, the wear resistance of GH4169 alloy under lower applied load and sliding speed can be improved with Ag implantation by ion beam assisted bombardment.


2011 ◽  
Vol 279 ◽  
pp. 22-27 ◽  
Author(s):  
Tong Kun Cao ◽  
Jun Peng Ge ◽  
Qi Long Yang

Al2O3/TiC ceramic composites with the addition of CaF2 solid lubrication were produced by hot pressing. The effects of various conditions on tribological behaviors of Al2O3/TiC/CaF2 have been studied. The sliding wear tests against cemented carbide and 45 steel were performed on the ceramic composites using ring-block method. Results showed that with the increase of load and sliding speed, the friction coefficient decreased. However, the wear rate increased slightly with the increase of load and decreased with the increase of sliding speed. At low speed, the abrasion resistance of Al2O3/TiC/CaF2 coupled with cemented carbide was better than with 45 steel, while the abrasion resistance showed little difference at high speed. The friction coefficients were little different when coupled with cemented carbide and 45 steel respectively. During the sliding process, at the initial stage, the friction coefficient was waved because the self-lubricating film was not formed on the worn surface; after sliding 628m, the friction coefficient was stable because the self-lubricating film was formed on the worn surface.


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