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Ion Implantation is a room temperature process that has been used extensively in the semiconductor industry since the 1970s and which has since found widespread application in most areas of engineering where it has affirmed itself as a proven method of extending tool life of machine parts up to ten times.
Ion implantation combines the two main strengthening mechanisms, namely, work hardening and alloying to yield a combination of properties which are unique. Ion implanted components are both wear and corrosion resistant and depending on the concentration of elements such as aluminum, chrome, molybdenum and vanadium, these properties persist during service even at elevated temperatures. However the main strength of this process is the possibility to harden the surface of low-alloyed steels, which are intended to function at low temperature and which soften when treated using most conventional surface modification processes. In this area, this process has practically no rivals.
Combining Ion implantation with conventional physical vapor deposition, results in the innovative IBAD/RIBAD coatings, where dense ceramic thin layers are fused into the surface of metallic components at room temperature (20 - 80 deg). This process combines the exceptional abrasive resistance of conventional PVD processes with the unrivalled corrosion resistance and low temperature processing of Ion Implantation.
| Ion implantation: |
- Increases the abrasive wear resistance
- Improves corrosion resistance
- Drastically reduces friction, thus decreasing adhesion and seizure.
- Is entirely environmentally friendly.
- Results in no discolouring or softening of tool.
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| Which tools can be ion implanted? |
- Metalworking tools (e.g. stamping, cutting and bending)
- Plastic moulding tools (e.g. injection nozzles and moulds)
- Cutting tools for plastics, rubber, wood and paper.
- Components
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| Why should you use Ion Implantation? |
When used for cutting tools (e.g. twist drills & milling tools), ion implantation results in:
- No more build up edge even when machining aluminium.
- Lower flank friction that permits higher cutting speeds.
- Less frequent tool regrinds.
- Drastically improved life of low alloyed woodworking tools.
When used for plastic injection-moulding tools ion implantation:
- Drastically reduces the adhesion of molten plastic to the mould surfaces.
- Aluminium and copper soft mould inserts can be hardened, thus reducing abrasive wear
- Increases the corrosion resistance of treated surfaces thus preserving surface finish and reducing rejects.
- Improves mould ejection process.
- Results in no damage to highly polished surfaces.
- Results in substantial reduction in wear and power consumption. i.e. less machine downtimes (eg: in arcemedian screws).
- Cuts down the number of processing steps. In fact ion implantation is the last step.
When used for stamping or bending tools incuding Punches, cold extrusion dies and various formers, ion implantation:
- Reduces friction resulting in better surface finish and reduced rejects.
- Extends tool life.
- Does not damage highly polished surfaces.
- Presents no health hazards.
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Case Study: Alumina coating on magnesium using IBAD
During this research project magnesium alloy (AM50) substrates were coated with alumina (Al2O3) using Ion Beam Assisted Deposition (IBAD).
The coating process
The correct amount of the coating material, alumina, was placed in the electron beam crucible. The specimens were weighed to the nearest 0.1-mg, and then mounted in groups of four on the specimen holder. The vacuum chamber was pumped down to a pressure of 1 x 10-6mbar. Towards the end of this procedure, the electron evaporator was switched on to raise the chamber temperature by a few degrees without evaporating the alumina. This was done to accelerate the out-gassing from internal surfaces, and to minimise the risk of excessive out-gassing during the coating process. The table was set to rotate and the substrates where sputter- cleaned by means of a high-energy (80keV) Ar+ ion beam for 20 minutes. The electron beam current was increased and directed by means of magnetic coils towards the alumina until the required evaporation rate was reached. Deposition was carried out at ambient temperature. Ion bombardment was continued throughout the evaporation process, and post implantation was carried out for 20 minutes.
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