POWDER METALLURGY PROCESSES Advantages Economic Near net shape

APPLICATIONS OF P/M PARTS Abrasives: metal polishing wheels, grinding media Agriculture: seed coatings, lawn

P/M PROCESSING Powder fabrication POWDER Size and shape characterization Microstructure (eg. dendrite size) Chemical

HORIZONTAL GAS ATOMIZATION Note: Most sketches and figures in this lecture are taken from

EFFECTS OF ATOMIZATION VARIABLES Finer particles size has finer dendrite and precipitate size and

OXIDE REDUCTION PROCESS FOR METAL POWDER FABRICATION

SHAPE OF CARBONYL POWDERS Purity ~ 99. 5%

ELECTROLYTIC PROCESS FOR POWDER PRODUCTION

POWDER CHARACTERIZATION Different Shapes and Sizes and shapes are important in blending and compaction.

MESH SIZES -100/+200 mesh: negative means particle goes through, positive means particle does not

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POWDER METALLURGY PROCESSES Advantages: Economic: (Near net shape) Unique applications: (filters, sintered bronze bearings, oxide dispersion strengthened alloys, cermets, cutting tools; rapidly solidified alloys, amorphous metals) Captive: (W filaments, ceramic components, electronic porous tantalum capacitors ) Conventional alloys Y T ODS & RSP alloys

APPLICATIONS OF P/M PARTS Abrasives: metal polishing wheels, grinding media Agriculture: seed coatings, lawn & garden equip. Aerospace: jet engines, heat shields, rocket nozzles Ceramics: high temperature components, thermal shields, fuel cells Electronic: capacitors, resistors, contacts Hardware: locks, wrenches, cutting tools Manufacturing: dies, tools, bearing surfaces Ordnance: ammunition, penetrators, fuses Pyrotechnics: explosives, flares

P/M PROCESSING Powder fabrication POWDER Size and shape characterization Microstructure (eg. dendrite size) Chemical homogeneity, and ppt. size Compaction PROCESSING Sintering Forging/Hot pressing Density, Porosity PROPERTIES Ductility, Strength Conductivity Other functional properties

HORIZONTAL GAS ATOMIZATION Note: Most sketches and figures in this lecture are taken from "Powder Metallurgy Science" by R. M. German, MPIF Publications. Do not reproduce.

VERTICAL GAS ATOMIZER

DETAILS OF DROPLET FORMATION

PARTICLE SHAPES FROM GAS ATOMIZATION

EFFECTS OF ATOMIZATION VARIABLES

EFFECTS OF ATOMIZATION VARIABLES Finer particles size has finer dendrite and precipitate size and gives better mechanical properties. However, handling and compaction more difficult for finer sizes.

CENTRIFUGAL ATOMIZATION

OXIDE REDUCTION PROCESS FOR METAL POWDER FABRICATION

CARBONYL PROCESS

SHAPE OF CARBONYL POWDERS Purity ~ 99. 5%

ELECTROLYTIC PROCESS FOR POWDER PRODUCTION

DETAILS OF ELECTROLYTIC Cu POWDERS

MECHANICAL MILLING

ATTRITION MILLING

MECHANICALLY MILLED POWDER SHAPE

POWDER CHARACTERIZATION Different Shapes and Sizes and shapes are important in blending and compaction. Often a mixed size is beneficial.

POWDER SIZE PARAMETERS

POWDER SIEVING

MESH SIZES -100/+200 mesh: negative means particle goes through, positive means particle does not go through. Thus, this mesh means particle sizes between 75 and 150 microns.

SEDIMENTATION TECHNIQUE

SEDIMENTATION

LASER TECHNIQUE

PARTICLE SIZE DISTRIBUTION

DIFFERENT PARTICLE SIZE DISTRIBUTIONS