The method of simulating the wear performance under working conditions using a high-temperature ultra-high-speed wear testing machine was adopted to study the effect of feed rate variation on the wear behavior and scraping performance of the AlSi/hBN sealing coating and TC4 simulated blades. The macro and micro morphology of the coating and blades were analyzed by stereomicroscope and scanning electron microscope (SEM). The phase composition of the coating was analyzed by energy dispersive spectrometer (EDS) and X-ray diffraction. The results showed that, under the conditions of temperature of 450°C, line velocity of 300m/s, and feed depth of 500μm, the change in feed rate significantly affected the macro and micro morphology and wear mechanism of the AlSi/hBN sealing coating-TC4 simulated blades. At low feed rates, severe wear occurred, mainly manifested as grooving, adhesion transfer, and overheating mechanisms. At medium to high feed rates, good machinability was observed, mainly manifested as cutting and transfer of coating material to the blades.

Sprayed deposits using conventional wire and powder materials open a wide range of possibilities to solve wear problems in engineering equipment. The option for new different spray technologies and consumables like nanostructured powder materials and nanocomposite cored wires has expanded the engineering possibilities. Cored wire technology allows the use of compositions that cannot be drawn into wire form like carbides in metallic matrix and high-temperature materials, thus intensifying the use of low operating cost welding and spraying processes to demanding wear applications. The objective of this work was to compare the mechanical characteristics and erosive wear performance of coatings obtained by Flame Spray and High Velocity Oxygen Fuel Spray using some selected powder and flexi-cord wire materials. The wear resistance of the coatings was determinate by slurry erosion wear test.

This work evaluates the potential of using twin wire arc (TWA) spraying as an alternative to metal active gas (MAG) overlay welding in the production of agricultural equipment. Corthal 65, a flux-cored wire electrode, was applied to different types of steel using each method. Some of the samples were tested in a lab and some were evaluated under actual use in the form of plow tips and harrow teeth. SEM and EDX analysis revealed the presence of Cr, Nb, and W carbides and Al-rich oxides in the hardfacing layer. Field-tested samples were assessed based on porosity and hardness, providing a measure of abrasive wear and impact resistance. The TWA-sprayed coatings performed as well as the MAG overlay welds, but their potential to improve productivity and reduce costs make them the more appealing option.

This work evaluates and compares the properties of weld overlays and thermal spray coatings produced using different feedstock materials. The mechanical and metallurgical characteristics of the coatings and their performance in corrosion and wear tests are discussed.

A series of abradability tests were conducted on AlSi-hBN coatings, which are commonly used in the compressor section of aeroengines for clearance control. The coatings were sprayed on test plates to a thickness of 1.9-2.0 mm and ground to a finish of 10 μm with 400 grit paper. The tests were carried out in an automated test rig with adjustable temperature, blade tip velocity, and incursion rate. The rig is configured such that the coatings are exposed to rotating blades, making contact with the tips as they pass. In this study, investigators monitored the number of contacts, removing and examining abraded coating samples at a given count total ranging from 200 to 4000. It was found that wear characteristics change with each contact between the coating and blade tip, indicating that pass number is a factor that must be considered when testing abradable coatings.

This work deals with the selection and deposition of wear-resistant coatings for ball valves used in coal slurry pipelines. Several NiCrBSi and WC-CoCr powders were deposited on stainless steel substrates by various methods, including atmospheric plasma spraying (APS) with and without post-process fusion, plasma transferred arc (PTA) spraying, and high-velocity oxyfuel (HVOF). The HVOF deposits had very low porosity and uniform carbide distribution in the metallic matrix. WC-CoCr coatings obtained by HVOF spraying were dense and well-adhered and experienced the least amount of mass loss in wear testing. As a result, they were recommended for testing in coal-water slurry pipelines and continue to perform well after more than two years.

In every industry wear plates and parts are demanded in heavy duty standards at cost effectiveness and environmental friendliness. For that reasons a new kind of coating technology was developed, and first applied on parts for agricultural machinery for getting results from the field. Simultaneously lab tests were done to compare the wear behaviour and performance of these sintered iron-based coatings with mainly chromium-carbides and borides in it, with other well known wear-resistant coatings like hard chrome, thermal sprayed coatings (Ni-matrix/WC), PTA welded coatings (Ni-matrix/WC, high speed steel) and processed steel like Hardox. Wear tests were performed under 3-body-abrasion as well as combined impact/abrasion conditions, respectively. Dry-sand rubber-wheel procedure according ASTM G65 was used to investigate low stress abrasion, whereas for high stress abrasion investigations a steel wheel was used. A special designed impeller-tumbler apparatus was used for combined impact and abrasion wear tests. Analysis after testing was done quantitatively by gravimetric mass loss, and qualitatively using SEM microscopy (edge stability, wear mechanisms). The ambition of this investigation is to secure the wear performance of the sintered iron-based coating at low production costs compared to well known anti-wear solutions applied in wear intensive industries.

In this work, mechanically alloyed Al–12Si/TiB 2 /h-BN composite powder was deposited onto an aluminum substrate by atmospheric plasma spraying. The results revealed that the mechanical alloying (MA) process has a significant effect on composite powder morphology and in-situ reaction intensity between the selective powders during plasma spraying. In addition, hexagonal boron nitride (h-BN) powder incorporated as a solid lubricant, which has excellent lubricating properties, decomposed into B and N and formed a solid solution after a long period of milling. More specifically, during plasma spraying a large amount of h-BN reacted with Al to form AlN. Unlubricated ball-on-disk testing ring was used to examine the anti wear performance of the coatings. The worn surfaces were examined using scanning electron and energy dispersive spectroscopy to elucidate the wear mechanisms operating at the sliding interface.

Environmental constraints on exposure to hexavalent chrome and its compounds has prompted increased utilization of HVOF thermal spray coating technology to implement new overhaul repairs for components that are currently chrome plated. Proposed 1998 EPA and OSHA standards place very tight restrictions on the Personal Exposure Limit (PEL) for hexavalent chrome, which will impact chrome plating operations and most likely attendant grinding operations. Historically, HVOF or D-gun type repairs involved bearing bores, journals on main shafts, mid span supports, dimensional restorations and clearance control applications predominantly on gas turbine engines. Currently, the Naval Aviation Depot Jacksonville is further developing HVOF capabilities for repairing all P-3 aircraft hydraulic component piston rods, landing gear piston struts, and landing gear axle journals with a tungsten carbide 17% cobalt coating in lieu of chrome plating. Once implemented, the repair technology will be transferred to other Naval aircraft components beginning with F14, F/A-18, EA-6B, E-6, and will eventually reduce personnel exposure to chrome and reduce environmental disposal costs for chrome plating waste by two-thirds. This paper provides a case study of the development and implementation of a chrome plating replacement for the P-3 aircraft including fatigue, corrosion, and seal wear testing, as well as HVOF parameter optimization development.