Electroless Nickel Coating of Boron Carbide Particles

摘要

This work is focused on electroless nickel coating on boron carbide (B_4C) particles. Using NiSO_4 as a Ni~(2+) source and NaBH_4 as a reducing agent, a Ni-B layer has been successfully coated onto the B_4C particles. Ni to B_4C ratio can be adjusted to achieve different coating thicknesses. Experimental observation and XPS results combining with theoretical calculation indicate that the amount of Sn~(2+) and Pd~(2+) used in the sensitization and activation steps is excessive, and can be further reduced. SEM shows that Ni coating has a tendency to encapsulate the B_4C particles. EDS results show the presence of oxygen in the Ni coating; thicker Ni coating has lower oxygen content. XPS confirms that B_2O_3 is formed on the surface of the coating. The Ni to B ratio in the coating was studied by XPS.