Method for manufacturing surge absorbing device

A method for manufacturing a surge absorbing device, the method comprising:

• forming a first plating layer and a second plating layer on a first end and a second end of a ceramic tube having a hollow space defined in the ceramic tube and exposed through the first and second ends, respectively;
• placing a surge absorbing element within the hollow space of the ceramic tube;
• disposing first and second brazing rings on the first plating layer and the second plating layer, respectively;
• disposing first and second sealing electrodes on the first and second brazing rings respectively;
• and
• melting the first and second brazing rings in an inert gas atmosphere to attach the first and second sealing electrodes onto the first plating layer and the second plating layer, respectively,
• wherein the forming of the first plating layer and the second plating layer on the first end and the second end respectively, comprises:
• etching the first end and the second end of the ceramic tube;
• forming first and second electroless plating catalyst layers on the etched first end and the etched second end respectively;
• forming first and second metal layers on the first end and the second end of the ceramic tube respectively using an electroless plating process;
• heat-treating the first and second metal layers,
• wherein the first and second metal layers respectively comprise a first nickel layer and a second nickel layer formed by the electroless plating process using a nickel plating solution comprising a nickel precursor and a reducing agent,
• wherein the nickel precursor comprises at least one selected from the group of consisting of nickel sulfate hydrate (NiSO4.6H2O) and nickel chloride hydrate (NiCl2.6H2O), and
• wherein the reducing agent comprises at least one selected from the group of consisting of sodium hypophosphite (NaH2PO2), sodium borohydride (NaBH4), dimethylamine borane ((CH2)2NHBH3), and hydrazine (N2H4).