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The Disfigurement And Microstructure-controlling Of The In-situ Synthesized Metal-ceramic Coating Containing TiB2 By PTA

Posted on:2009-03-21Degree:MasterType:Thesis
Country:ChinaCandidate:L J CaiFull Text:PDF
GTID:2121360272986125Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
As a typical boride ceramics, TiB2 ceramics have become a researched hot point because of its high melting point, good chemical stability, high hardness and good resistance to abrasion. But its sintering and spraying is difficult and can't achieve a heavy section, good metallurgical bonding and compact coating. Plasma-arc cladding, with simple attachments and high cladding efficiency, can be used in fabrication of the heavy section, good metallurgical bonding and compact TiB2 whisker.The TiB2 whisker is in-situ synthesized during the reaction of the alloy powders employing the plasma arc powder surfacing. The microstructure and properties have been researched by metallographic microscope, stereoscan electron microscope, X-ray diffractometer and microhardness tester. The kind of the blowholes, cracks and entrapped slag of the coating is determined. Summary and analysis of the impact of the dilution rate, the mount used of binder and drying temperature on the blowholes, cracks and entrapped slag is also taken. The formation mechanism of the flaws is discussed, and some measures are put forward to reduce the defects in the in-situ synthesized metal-ceramic coating containing TiB2 by PTA. The solidification process of the coating containing TiB2, that is different from other coating, is on an analysis. The results about this study show that the solidification process of the upper coating has taken before that in interior coating, because the melting point of TiB2 is very high and the TiB2 whisker gathered in the upper layer. This solidification process has an adverse impact on the elimination of defects.In this paper, the research on the influence of the powder composition to the TiB2 metal-ceramic coating is carried on. Different raw materials powder is in use to deposit the metal-ceramic coating containing TiB2, the Molding, structure and the hardness of which are analyzed. A good powder formula has been obtained. It is discovered that when Ti or C in coating excessive, a certain amount of TiC will be generated in the the metal-ceramic coating...
Keywords/Search Tags:PTA, in-suit synthesized, TiB2, disfigurement, microstructure-controlling
PDF Full Text Request
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