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Add trace amounts of copper nanoparticles on the microstructure and properties of the iron-based powder sintered parts

Author: LiGuangYuan
Tutor: ZhangXiaoYu
School: Changchun University of
Course: Materials Processing Engineering
Keywords: Nano-copper powder Iron-based powder Carburizing sintering Thermal stability
CLC: TF124.5
Type: Master's thesis
Year: 2010
Downloads: 41
Quote: 0
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Abstract


Sintering of powder metallurgy materials and products is an important means for the preparation of new materials and processing, is one of the key techniques that determine the quality of powder metallurgy products. Increasingly harsh due to the preparation and processing of new materials on the sintering method and process requirements, new technologies will continue to emerge. Nano technology has been rapid development in the last decade, the field of nanotechnology applications is constantly expanding and deepening. Based on nano-fine particles of small size effect, and has a high surface activity and low melting point, the introduction of nanomaterials in powder metallurgy technology has become an important research direction. This article is based on the above considerations, the focus on the impact of its products sintering and mechanical properties in the iron-based powder, add a small amount of nano-copper powder, a systematic study of the role of a small amount of nano-copper powder material in the iron-based powder metallurgy. First particle size of 50nm nano copper powder material compacts, the thermal stability of the nano-fine particles in the sintering process were studied, The result is that although single nano-fine particles having a the lower starting melting point of 477 ° C ~~ 490 ° C, but in improve with temperature and holding time, the sintering process, and with the nanoparticles grow, its melting point is also rising. Continuing driving force for this process is the reduction in the surface free energy. The tests showed that the nano copper particles is between 900 ° C to 960 ° C almost all melted, sintering materials for the bulk of the crude crystals. The results for the first time a small amount of nano-copper powder is added to the iron-based powder to achieve a low-temperature sintering (900 ℃ -960 ℃) provides a reliable test data. In a further pilot study, a small amount of nano-copper powder and the iron-based powder blend, nanometer copper-dependent microparticles surfactant nanometer copper microparticles on the boundary of the iron particles in the sintering process, with the increase in temperature and the holding time, continue to place long large, its growth mechanism is controlled by the diffusion mechanism of fusion. Nano-copper microparticles in the iron-based particles around wetting the surface of the iron particles grow up to form the cellular interface, connected to the iron-based particles, accelerated the process of diffusion and mass transfer between the sintering process of iron-based particles. Tests showed that the iron-based powder compacts adding 1.5wt% nano copper powder at 960 ° C, 1h under the conditions of carburizing sintering than conventional powder metallurgy process, first in the 1120 ° C to 1180 ° C high temperature sintering between then carburizing treatment can be removed from the high-temperature sintering using sintering and carburizing carburizing sintering to complete a one-time, saving a lot of energy consumption, and of great significance.

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CLC: > Industrial Technology > Metallurgical Industry > Metallurgical Technology > Powder metallurgy (metal ceramic technology ) > Powder molding, sintering and post-processing > Sintering process
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