Industrial application of low energy ion implantation

Transcription

1 Industrial application of low energy ion implantation

2 Presentation Outline OSTEC short introduction Nitriding of stainless steel by using ion treatment - motivation Industrial-suited nitriding system for stainless steel Results Applications Summary

3 Company Situated near Dresden, Germany Business: Heat treatment Service provider for metalworking industries Founded in 1994

4 Services Hardening und tempering Induction hardening Case hardening Carbonitriding Gas nitriding Plasmanitriding

5 Case hardening in multi-chamber furnaces Dimensions: 600 mm x 900 mm x 1100mm Net load per batch: 950 kg Temperatures: C Atmosphere: Methanol / Nitrogen

6 Induction hardening Surface hardening technology Layer thickness: mm Maximum size of workpieces: Diameter 600 mm Length 1400 mm

7 Carbonitriding / Case hardening in continuos feed hardening plants Small workpieces in bulk numbers Mass of workpieces: 0.5 g 1.2 kg

8 Gas nitriding Shaft furnaces Diameter: 900 mm Height: 2000 mm Gas mixture of ammonia und nitrogen

9 Plasmanitriding Supplier: RÜBIG, Wels (Austria) Equipped with pulsed-dc plasma generators Various batch sizes: Diameter mm Height mm

10 Motivation Austenitic stainless steels possess an outstanding corrosion resistance Low wear resistance and hardness Not hardenable by conventional techniques Conventional nitriding techniques (>450 C) lead to formation of CrN and subsequent corrosion Low process capability due to the (native) oxide layer ( self passivation )

11 Schematic pyrometer vacuum chamber gas inlet ion beam ion beam source sample holder ground pumping system

12 Nitriding system Vacuum chamber 1000x2400 Linear ion beam source Radiation heating Horizontal rotary cage with 18 mounting poles (satellites) Positioning by Lasersystem Pyrometer Base pressure 10-6 Pa Gas inlet: Nitrogen

13 Nitriding system

14 Principle of low energy broad beam ion source ion beam source neutralizer PBN - + plasma source extraction system mic crowave ge enerator plasma e - ion beam substrate λ/4 antenna permanent magnetic system ( T) - + acceleratorvoltage beamvoltage + -

15 Ion beam source

16 Pulsed mode of the ion beam Modern ion sources provide high ion current densities High ion impact is related to backsputtering, increasing roughness and internal stress Independent control of temperature, ion energy and current density is not possible when substrate is heated directly by ion beam Objective: decoupling of substrate heating and ion implantation Using an electronic beam switch

17 High Voltage Pulse Generator RUP3-5ion Designed for pulsed mode of ion sources Voltage: up to 5 kv Current: up to 6 A peak current Maximum power output: 10.5 kw Frequency: 0 10 khz Duty cycle: % Waveform: square wave Ultrafast rise and fall times ( < 100 ns at lower voltages)

18 Nitrogen content vs. depth 4 0 Stickstoffgehalt (at.%) N ie d r ig e r A r b e its d r u c k 1.5 h 6 h 5 % 1 0 % 1 5 % 2 0 % 3 0 % 3 0 % 5 0 % % T ie f e ( µ m )

19 Hardness

20 Roughness 0,5 0,4 Roughness (µm m) 0,3 0,2 0, Duty cycle (%)

21 Wear Specific Wear Dept th (µm/m) X6CrNiMoTi , Untreated X90CrMoV18, N/cm 2 X6CrNiTi18.10, N/cm 2 X6CrNiMoTi , N/cm 2 X6CrNiMoTi , N/cm 2

22 Applications Food- und packaging industries Chemical und pharmaceutical industries Medical Engineering Equipment for microelectronics Engineering of textile machines Special areas of automotive industrie

23 Ball joints for automotive applications

24 Ball joints for automotive applications Ion beam treated Untreated Hardness [G GPa] Position [mm]

25 Packages for textile machines (AISI 304) Filaments with high speeds lead to high wear rates Humid atmosphere Conventional heat treatment Salt bath nitriding Problem: corrosion

26 Packages for textile machines

27 Packages for textile machines Ion beam treatment Process temperature: 380 C Process time: 30 min Surface hardness: 900 HV0.1 Layer thickness : 5 µm No corrosion! (salt spray test 96h)

28 Benefits Enhancement of surface hardness Significant improvement of wear resistance No affect on corrosion resistance Alteration of surface roughness dependent on process parameters Treatment at low temperatures No alteration of basis material properties Reduction of fretting fatigue No colour change of the treated surface

29 Summary Nitriding technique especially designed for corrosion resistant stainless steel Nitriding plant with industrial suited dimensions Linear ion beam source of 2000 mm Operated in a pulsed mode using a beam switch Increased surface hardness Improved wear resistance Retention of corrosion resistance

30 Acknowledgements Dr. D. Manova H. Neumann

31 Many thanks for your kind attention! OSTEC Oberflächen- und Schichttechnologie GmbH Am Bahndamm 3 D Klipphausen / Germany Phone: Fax: