Corrosion Resistance of P/M S.St. Richard R. Phillips, Engineered Pressed Materials Dennis Hammond Apex Advanced Technologies, LLC

Objective Using 316L, 17-4ph, 409LCb & 434L Achieve higher densities Higher densities at lower sintering temperatures Obtain good corrosion resistance

History Historically difficult to get high density Compressibility limiting factor Work hardening during pressing High surface oxides on powder Limited oxide reduction in sintering and densification Lower densities interferes with corrosion resistance

Water atomized 316L 3200 ppm O2 5200X

Gas atomized 316L 150 ppm O2 5200X

Powder Preparation 100 mesh standard powders of 316L, 17-4ph, 409LCb & 434L A group with 0.75 % Lithium Stearate A group with an Activation Technology TRS bars pressed at 690 Mpa (50TSI)

Activation Technology Blend Additive/Lubricant Master Batch Hydrostatic distribution of additives & lubricant during compaction Particles are aligned in a best fit arrangement Density gradients eliminated Activation is initiated in the delubing stage and finalized in the early stage of sintering

Density Gradient – Shape Retention EPM

Lithium stearate Activation Technology

Compressibility g/cm3 at 690 Mpa (50TSI) Material Li Str. Activation 316L 6.83 6.76 17-4ph 6.28 6.23 409LCb 6.63 6.58 434L 6.51 6.47

Processing TRS bars delubed at 400OC (750OF) in Air Sintering in a H2 box furnace with a slow cool > 1 hr. Sintering in a continuous vacuum furnace with a 2 bar fast N2 quench < 10 min. Sintered at: 1120 (2050), 1177 (2150), 1232 (2250), 1288 (2350), 1343 (2450) & 1388OC (2530OF) Time at temperature 45 min.

Atmosphere Box Furnace

Continuous Vacuum N2 quench

Sintering size change and densification

ASTM B895 Standard for Test Method 2 For alloy screening and process optimization

D X C B A 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl 316L ¢C (¢F) 1120 (2050) 1177 (2150) 1232 (2250) 1288 (2350) 1343 (2450) 1388 (2530) Li Str ATMO D X C B Activ. ATMO A Li Str VAC Activ. VAC 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

C X B A D 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl 17-4PH ¢C (¢F) 1120 (2050) 1177 (2150) 1232 (2250) 1288 (2350) 1343 (2450) 1388 (2530) Li Str ATMO C X B Activ. ATMO A Li Str VAC D Activ. VAC 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

D X C A B 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl 409Cb ¢C (¢F) 1120 (2050) 1177 (2150) 1232 (2250) 1288 (2350) 1343 (2450) 1388 (2530) Li Str ATMO D X C Activ. ATMO A Li Str VAC B Activ. VAC 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

D X C B 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl 434L OC (¢F) 1120 (2050) 1177 (2150) 1232 (2250) 1288 (2350) 1343 (2450) 1388 (2530) Li Str ATMO D X C Activ. ATMO B Li Str VAC Activ. VAC 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

BETTER CORROSION RESISTENCE Conclusion BETTER CORROSION RESISTENCE Higher density Faster cooling rate Activation Technology Higher density at a lower temperature ` Better response with continuous Vacuum Best corrosion resistance