1. The use of platinised titanium anodes in chrome plating applications in the aircraft industryby
Peter Morrell and Joerg Wurm,
Composite Metal Services, Shipley, England
and Metakem GmbH, Usingen, Germany

2. Advantages and disadvantages of chrome plating
The mechanical and chemical properties of Cr
the simplicity of the electroplating process
Disadvantages
A very poor electroplating efficiency and a bad throwing power of the bath

3. Demands for making a perfect chrome coating
Shaped anode with small anode-cathode gap
Assembly of anode and component outside the bath
Good current distribution in the anode because of the small anode – cathode gap
Good electrolyte exchange to maintain chrome
concentration and to extract the bubbles
Safe and good contact to the component especially
for high current applications

4. Benefits of working with platinised titanium anodes
Remains active for a large number of coating cycles
Shaped (conforming) anodes allow ‚ better‘plating to size
Platinised titanium mesh anodes facilitate the
electrolyte exchange
Allows to solve complex plating tasks like simultaneous plating on a multiple of faces and reduces the number of heat treatment cycles

5. Plating the inside of a recessed volume

6. Plating of a welded-on flange

7. Plating of a ball-and-socket joint

8. Plating of six cylindrical faces of an axle

9. Comparison of plating with lead anodes (upper part) and with cylindrical platinised mesh anodes (low)

10. Plating on nine faces in one cycle of the ‘Sliding tube’
Barrel part for shock absorption
Left axle
Right axle
Brake flange

11. Assembled ‘Sliding Tube’ with Pt/Ti anodes over the plating tank

12. Benefits of using conforming anodes for the example plating of the ‘Sliding Tube’
Reduction to a single assembling operation
Single de-imbrittlement cycle
Large reduction of the grinding/ resizing effort
Shorter total plating time and plating tank occupancy
Overall reduction of maintenance time
Overall reduction of manpower for maintenance

13. The future of chrome plating
Chrome plating can be processed without hazards to health and environment with a safe technology
Chrome coatings itself are not toxic and there is no argument against using them
Replacing chrome plating by CVD, PVD or spraying is possible but not flexible compared to electroplating
The aim should be to look for another electroplating process with properties comparable to chromium

14. Thanks
We thank Messiers Dowty, Messiers Services, Lufthansa and Smiths Aerospace for allowing us to present samples of their daily tasks. We appreciate that very much as it demonstrates to many users who still plate 100 microns to a pieces and grind it down to a homogeneous layer of 50 microns what can be improved in their plating process.
We specially thank Mr. Knauthe for making the drawings and of course you for your patience.