Effects of B(CH3O)(3) content on a PACVD plasma-boriding process

Investigations have been undertaken on the process of boriding by pulsed-DC plasma-assisted chemical Vapor deposition technique (PACVD). The substrate material was 42CrMo4 steel. Boriding agent was trimethylborate [B(CH3O)(3) ]. The flow rates of Ar and H-2 were 2700 ml/min and 540 ml/min, respective ly, the total pressure in chamber during plasma boriding process was 800 Pa , the boriding temperature was 830 degreesC, the boriding time was 1 h and the flow rate of B(CH3O)(3) was from 0.1 g/h to 1 g/h. A mass spectrometer was used to detect the ionization of B(CH3O)(3). Experimental results showe d that the boronized layer could be obtained under this testing process and the thickness of boronized layer increases with increasing the flow rate o f B(CH3O)(3). On the other hand, the B-C layer would be formed on the boron ized layer when the flow rate of B(CH3O)(3) was higher than 0.5 g/h and the thickness of B-C layer also increases with increasing the flow rate of B(C H3O)(3). (C) 2000 Elsevier Science B.V. All rights reserved.