Wear-resistant nickel-based laser clad coatings for high-temperature applications

Abstract

The effect of high-temperature processing on laser clad Ni-based coatings is studied. Annealing at 1025°C forms thermally stable framework structures with large chromium carbides and borides. As a result, improved hardness and wear resistance of the coating are maintained when heated to 1000°C. Stabilizing annealing also increases the frictional thermal resistance of the NiCrBSi coating. Under high-speed (3.1-9.3 m / s) sliding friction, when the surface layer temperature reaches about 500 -1000°С and higher, the wear resistance of the coating increases by 1.7 -3.0 times. The proposed approach to the formation of heat-resistant coatings is promising, in particular, for a hot deformation tool and other components of metallurgical equipment operating under high thermal and mechanical loads. Such products include crystallizer walls of continuous casting machines. For the walls, the development of laser cladding technology for wear-resistant composite coatings on copper alloys is relevant as an alternative to thermal spraying. The cladding of composite NiBSi-WC coatings of 0.6 and 1.6 mm thickness on a Cu-Cr-Zr bronze substrate heated to 200 -250°C with a diode laser is considered. The presence of boron causes the formation of the W(C, B) carboboride phase, whose hardness is higher than that of WC in the initial powder. Depending on the thickness of coatings and, accordingly, on the duration of heating and the subsequent cooling, the process of secondary carboborides precipitation from the solid solution can be suppressed (in the "thin" coating) or activated (in the "thick" coating). This leads to a higher wear resistance under friction sliding 1.6 mm thickness coating.

The potential use of laser cladded functionally graded materials to mitigate degradation in boiler tube heat exchangers for power plant applications: A review

“…Due to declining performance characteristics, nickel-based coatings are often limited in their application at high temperatures. For instance, NiCr-based coatings deposited via laser cladding and plasma spraying were reported to lose hardness and wear resistance at temperatures exceeding 700°C, making them prone to degradation [90]. Makarov et al [90] stated that tungsten carbide phases can be used to improve the microstructural properties of Ni-based coatings to enhance their wear resistance at elevated temperatures.…”

“…For instance, NiCr-based coatings deposited via laser cladding and plasma spraying were reported to lose hardness and wear resistance at temperatures exceeding 700°C, making them prone to degradation [90]. Makarov et al [90] stated that tungsten carbide phases can be used to improve the microstructural properties of Ni-based coatings to enhance their wear resistance at elevated temperatures. NiBSi-WC composite coating deposited on CuCrZr substrate by laser cladding was also investigated.…”

“…By contrast, copper alloys can form a good bond with Ni-based alloys in producing coatings meeting the requirements for high temperature, wear, and corrosion resistance of heat exchangers.

Figure 19 NiCrBSi coating on CuCrZr substrate (a) before annealing (b) after annealing with large chromium carbides (Cr 7 C 3 ) and chromium borides (CrB) phases that improved the wear and hardness properties [90].

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“…NiCrBSi coating on CuCrZr substrate (a) before annealing (b) after annealing with large chromium carbides (Cr 7 C 3 ) and chromium borides (CrB) phases that improved the wear and hardness properties [90]. …”

Развитие Современных Комбинированных Способов Модифицирования Металлических Поверхностей На Основе Лазерных И Деформационных Наноструктурирующих Технологий

“…Применительно к развитию технологий лазерной наплавки предложен новый подход к получению износостойких хромоникелевых покрытий с особо высоким уровнем теплостойкости проведением комбинированной лазерно-термической обработки, включающей лазерную наплавку и отжиг при температурах 1000-1050°С [1]. Высокотемпературный отжиг формирует в покрытии высокопрочный термически стабильный каркас из крупных карбидов и боридов хрома, обеспечивая рост износостойкости (по сравнению с износостойкостью наплавленного покрытия) при абразивном воздействии и высокоскоростном (3,1-9,3 м/с) трении скольжения -в условиях сильного фрикционного нагрева [2,3].…”