Surface Treatment and Coating of PM Components
Surface Treatment and Coating of PM Components
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粉末冶金部件的表面处理和涂层
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
T. Bell
中科院分区：
文献类型：
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作者：
T. Bell
回顾了适用于粉末冶金部件的表面工程技术范围，并强调了能够优化基材和涂层性能以提供所需整体性能的清晰设计概念的重要性。使用现有技术可以毫无困难地处理完全致密的组件。以 ASP 23 冷成型模具为例，经过硬化、TiN/TiC 化学气相沉积涂层以及消除工具粘连并提高模具润滑性的再硬化处理后，该模具的寿命延长了 25 倍。然而，在处理多孔部件时遇到了问题。盐浴处理后工艺流体或淬火介质的滞留会加速腐蚀，并可能使任何后续层降解。密度的变化也使得难以生产一致的外壳和淬火速率，从而难以生产一致的性能。这些问题可以通过蒸汽处理来密封孔隙或通过现代气体和等离子体氮碳共渗工艺来克服，这些工艺可以成功地在孔的内表面上产生外壳。最新一代的涂料是通过双重加工生产的，例如通过热喷涂或激光或电子束熔化热喷涂沉积的涂层来固结。下午/0570
The range of surface engineering technologies applicable to PM components is reviewed and the importance of a clear design concept capable of optimizing substrate and coating properties to provide the desired overall performance is emphasised. Fully dense components can be processed without difficulty using established technology. An example is given of ASP 23 cold forming dies, which have shown a 25 fold increase in life following a hardening, TiN/TiC chemical vapour deposition coating, and rehardening treatment that eliminates pickup on the tool and also improves die lubricity. However, problems have been encountered in the treatment of porous components. Retention of process fluid following salt bath treatment or of quenching media can accelerate corrosion and is likely to degrade any subsequent layer. The variation in density also makes it difficult to produce consistent cases and quenching rates and hence consistent performance. These problems can be overcome by steam treatment to seal porosity or by the modern gaseous and plasma nitrocarburising processes which can successfully produce cases on the internal surfaces of pores. The latest generation of coatings is being produced by duplex processing, e.g. the consolidation by hipping or by laser or electron beam melting of coatings deposited by thermal spraying. PM/0570