METALOGRAFI difusi

DIFFUSION IN SOLID

DIFFUSION Mass transport by atomic motion. Diffusion is a consequence of the constant thermal motion of atoms, molecules and particles that results in material moving from areas of high to low concentration

PERCOBAAN SEGELAS AIR YG DITETESI TINTA

• Self-diffusion: In an elemental solid, atoms also migrate. FENOMENA DIFUSI • Self-diffusion: In an elemental solid, atoms also migrate. specific atom movement A B C D After some time

FENOMENA DIFFUSION • Interdiffusion (impurity diffusion): In an alloy, atoms tend to migrate from regions of high concentration to regions of low concentration. After some time Initially

HOW TO QUANTIFY DIFFUSION ?

Steady-State Diffusion Kondisi Mantap D adalah koefisien difusi, dC/dx adalah variasi konsentrasi dalam keadaan mantap di mana C0 dan Cx bernilai konstan C1 C2 x x1 x2 Hukum Fick Pertama

Nonsteady State Diffusion Ini merupakan Hukum Fick Ke-dua xa x Ca Cx2 materi masuk di xa materi keluar di x x Cx0=0 Cx1 t2 t1 t=0

Koefisien diffusi Dari hasil eksperimen diketahui bahwa koefisien difusi D

PROSES DIFUSI Atoms in solid materials are in constant motion, rapidly changing positions. For an atom to move, 2 conditions must be met: There must be an empty adjacent site, and The atom must have sufficient (vibrational) energy to break bonds with its neighboring atoms and then cause lattice distortion during the displacement. There are 2 dominant models for metallic diffusion: Vacancy Diffusion Interstitial Diffusion

VACANCY DIFFUSION increasing elapsed time

Syarat vacancy diffusion Ukuran atom struktur kristal ada vacancy Valensi

Interstitial Diffusion

LOMPATAN ATOM

APLIKASI

CARBURIZING Furnace for heat treating steel using carburization. Carburizing is the addition of carbon to the surface of low-carbon steels at temperatures ranging from 1560°F to 1740°F. Hardening is achieved when a high carbon martensitic case with good wear and fatigue resistance is superimposed on a tough, low-carbon steel core.

Case hardening

A hot-dip galvanizing Galvanized i-beams.

Doping 1. Deposit P rich layers on surface. 2. Heat. 3. Result: Doped • Doping silicon with phosphorus for n-type semiconductors: • Process: 3. Result: Doped semiconductor regions. silicon magnified image of a computer chip 0.5 mm light regions: Si atoms light regions: Al atoms 2. Heat. 1. Deposit P rich layers on surface.

Thermal Barier Coating ( TBC )

TERIMA KASIH