From: barlow@birch.ee.vt.edu (Fred Barlow)
Newsgroups: sci.materials
Subject: Re: Platinum coating of high temperature substr
Date: 21 Oct 1994 20:56:24 GMT
Organization: Virginia Tech.

Sounds like you have an adhesion problem.  Many metals like gold and silver 
do not adhere well to most substrates like allumina.  One approach is to use 
a thin adhesion layer of Cr or Ti (~ 50 - 100 Angstroms), since these metals 
act like natural glues. Followed by a heat treatment at a few hundred deg
degees celcius to promote adhesion.  
I have used this process with evaporation and obtained excellent results on 
allumina and glass substrates for both silver and gold, this may also work 
with platnium.

Good luck,

Fred Barlow