TRIBOLOGICAL PROPERTIES OF AL2O3-ZrO2 COMPOSITE COATING BY LUBRICATION

Tribological investigations had been carried out on the plasma coating (Al2O3+ ZrO2) below dry and moist abrasion stipulations according to ASTM G134. Commercial motor oil 20W40 was used as a lubricant. At a rotational speed of 200 rpm, all experiments were carried out with ordinary loads of 10, 15 and 20 Nm. Electron microscopy for scanning and AFM was used to study of the layer sprayed with paint. The outcomes of the SEM and AFM evaluation confirmed that abrasive wear is normally decided by abrasive wear in dry abrasive conditions. The lubrication and moisture check confirmed a major reduce in wear from 10 to 15 N below regular loading, and a corrosion fee larger than 15 N was once discovered below regular loading. No impact of lubrication on wear used to discovered at high loading. No impact of lubrication on wear used to be discovered at high loads. It was also cited that the plasma coating manner to improve wear resistance. The experimental statistics acquired in this study are tremendous engineering functions such as reducing equipment and internal combustion engines.

An Overview of Wear and How to Improve Wear Resistance

Wear is discussed in this study, as well as its impact on component performance and lifespan. It was mentioned how researchers are working to enhance the performance of materials. Due to enhanced hardness and finer grain structure, increased wear resistance has been recorded. Due to the particle strengthening process, it has also been observed that particle reinforcement improves wear resistance.

CARBON NANOTUBES REINFORCED ZIRCONIA COMPOSITES FOR ARTFICIAL HIP JOINTS BEARING SURFACES

This research focuses on the properties and capabilities of carbon nanotubes (CNTs) as reinforcing agents in ceramic composite bearing components. The addition of CNT to pure ceramics can form composites with much better performance than conventional ceramics for various applications. The study was started from the pure ceramics in their use as a component of bearing total hip arthroplasty and the damage that occurred after implantation. The study covers factors that cause degradation of conventional ceramics introduction of properties and use of CNTs as new reinforcing agents for ceramic composite materials widely used sintering method and the heat and pressure parameters used during the sintering process to meet the standards for the manufacture of Total Hip Arthroplasty (THA) bearing component. The contact and buckling behaviors of the CNTs influence the composites friction properties. The presence of CNT until 20 wt% of CNT exhibited improve wear resistance with lower friction with the increase of weight percent. CNT reinforced ceramic coating might be capable to withstand high load-bearing conditions. Plastic deformation can be one of the critical processes in wear in the ceramics wear mechanism. Other processes are cracking and chemical reaction. The microstructures and porosity take an important role in indicating the ceramics wear properties and wear mechanisms.

Tribological Performances of Modified Babbitt Alloy Under Different Sliding Modes

This paper aims to improve wear resistance of bare Babbitt modified by CuLa and evaluates the effect of different sliding modes on tribological properties of bare Babbitt, Babbitt modified by 0.5 wt% CuLa (marked by mbabbitt-1), and Babbitt modified by 1 wt% CuLa (marked by mbabbitt-2). First, bare Babbitt was modified with different contents of CuLa. The microstructure, microhardness, and wettability of Babbitt were tested and studied. Then, the tribological properties of bare Babbitt, mBabbitt-1, and mBabbitt-2 were conducted by the reciprocating mode and unidirectional mode under the lubricated condition. The results showed that the SnSb grain of the modified Babbitt was refined and uniformly distributed. The microhardness of mBabbitt-1 was higher than that of bare Babbitt and mBabbitt-2. Compared with bare Babbitt, the wettability of mBabbitt-1 and mBabbitt-2 was improved. Anti-friction and wear resistance of specimens under the reciprocating mode were better than that of specimens under the unidirectional mode, which was attributed to low strain and equivalent stress of bare Babbitt under the reciprocating mode. Moreover, anti-wear of bare Babbitt was improved by adding CuLa due to refined grain and high microhardness.

Development of Cast Cobalt Alloy for SRP Valve Pairs

The work is devoted to studying of possibility to manufacture cast ball valves of sucker rod oil pumps instead of those manufactured by the powder metallurgy method from Stellite 20 alloy. It is shown that Stellite 20 cast alloy includes about 20% μ and σ brittle phases, destruction whereof, in case of impact-abrasion wear, when excavating oil, leads to quick failure of the valve pair. A new cast cobalt alloy not containing brittle phases has been developed instead of Stellite 20 alloy, which allowed to improve wear resistance of cast valve pairs to the level of valves produced by the powder metallurgy method.

Research of Microstructure, Friction and Wear on Siliconized Aluminum-Bronze With Different Silicon Powder Ratio

In order to enhance the wear resistance without changing the mechanical properties of the substrate, the aluminum-bronze alloy was siliconized by pack cementation in this paper. Its surface hardness was improved by a certain thickness of siliconized layer. The different processes and their influences on the siliconized layer and the substrate were investigated by changing the ratio of siliconizing powder. The microstructure and phase composition of the siliconized layer was detected and analyzed. Compared with the non-siliconized sample, the hardness of the siliconized layer of 30% Si content is increased by 93.54%, and the average friction coefficient is reduced to 40.38%. The maximum thickness of siliconized layer in the experiment is 200 μm when the silicon powder content is 30%. It can be concluded that surface siliconizing is effective to reduce the friction coefficient of aluminum-bronze and improve wear resistance.

Alloying Hard Metals of Tungsten Carbide-Cobalt System with Vanadium and Rhenium to Improve Wear Resistance

Vanadium and rhenium modified samples of hard alloy systems WC-VC-Co, WC-ReC-Co (grade VK-6) are considered when testing their wear resistance and hardness, in comparison with the serial alloy VK-6. The samples of the groups differed in the content of vanadium and rhenium, and additional purification of the raw material. The reason for the reduced wear resistance of the VK-6 alloy, caused by the structural features and the presence of impurities, is revealed. Sample test results: WC-VC-Co alloys in the VC concentration range of 1.0-16.0% by weight, turned out to be ≈ 3% harder and 30-90% more resistant to wear; WC-ReC-Co alloys, at a ReC concentration of 1-5% by weight, turned out to be ≈3% harder and 38.5% more resistant to wear; additional purification of the W-raw material of the WC-ReC-Co alloy with a ReC concentration of 5% by weight, in comparison with the alloys: VK-6 and VK-6 modified with 5% rhenium without additional purification, increased wear resistance from 38.5% (alloy "VK-6 modified with 5% rhenium"), up to 57.0% (single) and 65.3% (three times purification) alloy "VK-6 modified with 5% rhenium with additional purification". Experimental-industrial tests of products - surfacing on turning tools made of VK-6 alloy with VC 3% wt., Revealed that they were 30-35% more resistant to wear than samples from the serial VK-6 alloy, with an equal content cobalt; this means an increase in the resource of the tool by 30-35%. It was recommended to introduce alloying and additional purification of tungsten raw materials.

Wear Characteristics of Superalloy and Hardface Coatings in Gas Turbine Applications–A Review

In the gas-turbine research field, superalloys are some of the most widely used materials as they offer excellent strength, particularly at extreme temperatures. Vital components such as combustion liners, transition pieces, blades, and vanes, which are often severely affected by wear, have been identified. These critical components are exposed to very high temperatures (ranging from 570 to 1300 °C) in hot-gas-path systems and are generally subjected to heavy repair processes for maintenance works. Major degradation such as abrasive wear and fretting fatigue wear are predominant mechanisms in combustion liners and transition pieces during start–stop or peaking operation, resulting in high cost if inadequately protected. Another type of wear-like erosion is also prominent in turbine blades and vanes. Nimonic 263, Hastelloy X, and GTD 111 are examples of superalloys used in the gas-turbine industry. This review covers the development of hardface coatings used to protect the surfaces of components from wear and erosion. The application of hardface coatings helps reduce friction and wear, which can increase the lifespan of materials. Moreover, chromium carbide and Stellite 6 hardface coatings are widely used for hot-section components in gas turbines because they offer excellent resistance against wear and erosion. The effectiveness of these coatings to mitigate wear and increase the performance is further investigated. We also discuss in detail the current developments in combining these coating with other hard particles to improve wear resistance. The principles of this coating development can be extended to other high-temperature applications in the power-generation industry.