A Study of the Products of Ultraviolet Irradiation of Palladium‐Containing Catalysts for Electroless Metal Deposition

Ultraviolet light has a marked effect on the Sn--Pd species used in electroless metal deposition, both when Sn(II) and Sn(IV) solutions are as the sensitizers. Some information on this effect has been gained by determining the amount of Pd washed off during the postactivation rinse. The fact that from the irradiated Sn(IV)--Pd species less Pd rinses off than the nonirradiated indicates that the light does not simply break the bonds attaching the Pd allowing it to be removed by rinsing. More Pd seems to be bound when Sn(II) is the sensitizer than when Sn(IV) is, indicating that mechanisms of Sn--Pd attachment may be different. Nevertheless, whether or Sn(IV) was the sensitizer there remains a significant amount of Pd on irradiated and rinsed substrate that has been altered to render it incapable of becoming catalytic in the metal plating bath.17 refs.--AA