Model experiments of gaseous boriding with a BCl3-H2 mixture

Armco-iron was borided with a BCl3-H2 mixture (0.6 to 2.2 volume percent BCl3) in a quartz glass reactor at temperatures of 1023, 1123 and 1223 K. In 2.5 hours FeB and Fe2B coatings of 30 to 120 μm thickness were formed. The mass changes of the borided samples were compared with the layer thickness or with the calculated boron absorption as a function of the test parameters. Conclusions are drawn with regard to coating kinetics and to the technical applicability of the BCl3-H2 mixture for coating