Characterization of boride coatings on a ductile cast iron

In this work, the EN-GJS-400-15 cast iron was pack-borided in a powder mixture composed of 5% B₄C, 5% NaBF₄ and 90% SiC at the three temperatures: 900, 950 and 1000°C for 2, 4 and 6 h, respectively. The pack-borided EN-GJS-400-15 cast iron was characterized by the following experimental techniques: optical microscopy, XRD analysis and Microhardness Vickers tester. The growth kinetics of boride layers was also investigated. As a consequence, the boron activation energy was found to be 212.28 kJ mol^–1 for the EN-GJS-400-15 cast iron. Based on a regression model, a useful equation was derived to estimate the boride layer thickness as a function of the boriding parameters (time and temperature). A good agreement was then obtained between the predicted values of boride layers thicknesses and those measured experimentally. In addition, an iso-thickness diagram was proposed to be used as a simple tool to select the boride layers thicknesses according to the potential applications of EN-GJS-400-15 cast iron in industry.     

Structural properties of boride coatings for triboengineering

Boride coatings on steels of different classes are rather widely used for decreasing the intensity of abrasive wear and thermal degradation of the surface of machine parts and equipment. Borating can also be an efficient means for increasing the wear resistance of heavily loaded friction units. The present work presents results of an investigation of the structure and wear resistance of boride coatings on steel 15N3MA. The optimum structure of the boride layer and the range of application of boride coatings are determined.Translated from Metallovedenie i Termicheskaya Obralbotka Metallov, No. 6, pp. 35–38, June, 1995.     

原位合成的硼化物类高温陶瓷涂层的研究

采用等离子弧堆焊设备，通过钛合金和硼合金粉末之间的高温冶金反应，在普通碳钢表面制备了合TiB2的金属陶瓷层。试验结果表明：通过改变B4C含量，可得到不同的组织，并且随着B4C含量增加，基体组织中Fe2B数目也增加，强化基体，使堆焊层上表面硬度增加。