Contact Enhancement
Durable surface finishes provide a hard and chemically inert contact area for test probes and electrical connectors. A rhodium tip coating is utilized in high volume automated test environments where the probe must survive millions of cycles against abrasive solder targets. This material offers exceptional resistance to oxidation and wear compared to standard gold or silver finishes.
Mechanical Performance
Electroplating techniques deposit a thin layer of this platinum group metal onto a base of heat treated beryllium copper or steel. Because a rhodium tip coating has a high Vickers hardness, it resists the deformation and flattening that typically occurs with softer contact materials. Low contact resistance is maintained even in the presence of thin oxide films on the board under test.
The inert nature of the metal prevents the build up of solder contaminants on the probe surface. Frequent cleaning cycles are reduced, which increases the total throughput of the testing station. Solid metallurgical bonding between the rhodium and the base metal ensures the tip does not delaminate under high vertical pressure.
Application Limit
Brittleness of the layer can lead to cracking if the probe is subjected to excessive lateral forces. Cost considerations restrict its use to high duty cycle applications.
